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llvm-project/llvm/lib/Target/PowerPC/PPCVSXSwapRemoval.cpp

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[PPC64LE] Remove unnecessary swaps from lane-insensitive vector computations This patch adds a new SSA MI pass that runs on little-endian PPC64 code with VSX enabled. Loads and stores of 4x32 and 2x64 vectors without alignment constraints are accomplished for little-endian using lxvd2x/xxswapd and xxswapd/stxvd2x. The existence of the additional xxswapd instructions hurts performance in comparison with big-endian code, but they are necessary in the general case to support correct semantics. However, the general case does not apply to most vector code. Many vector instructions are lane-insensitive; they do not "care" which lanes the parallel computations are performed within, provided that the resulting data is stored into the correct locations. Thus this pass looks for computations that perform only lane-insensitive operations, and remove the unnecessary swaps from loads and stores in such computations. Future improvements will allow computations using certain lane-sensitive operations to also be optimized in this manner, by modifying the lane-sensitive operations to account for the permuted order of the lanes. However, this patch only adds the infrastructure to permit this; no lane-sensitive operations are optimized at this time. This code is heavily exercised by the various vectorizing applications in the projects/test-suite tree. For the time being, I have only added one simple test case to demonstrate what the pass is doing. Although it is quite simple, it provides coverage for much of the code, including the special case handling of copies and subreg-to-reg operations feeding the swaps. I plan to add additional tests in the future as I fill in more of the "special handling" code. Two existing tests were affected, because they expected the swaps to be present, but they are now removed. llvm-svn: 235910
2015-04-28 03:57:34 +08:00
//===----------- PPCVSXSwapRemoval.cpp - Remove VSX LE Swaps -------------===//
//
// The LLVM Compiler Infrastructure
//
// This file is distributed under the University of Illinois Open Source
// License. See LICENSE.TXT for details.
//
//===---------------------------------------------------------------------===//
//
// This pass analyzes vector computations and removes unnecessary
// doubleword swaps (xxswapd instructions). This pass is performed
// only for little-endian VSX code generation.
//
// For this specific case, loads and stores of v4i32, v4f32, v2i64,
// and v2f64 vectors are inefficient. These are implemented using
// the lxvd2x and stxvd2x instructions, which invert the order of
// doublewords in a vector register. Thus code generation inserts
// an xxswapd after each such load, and prior to each such store.
//
// The extra xxswapd instructions reduce performance. The purpose
// of this pass is to reduce the number of xxswapd instructions
// required for correctness.
//
// The primary insight is that much code that operates on vectors
// does not care about the relative order of elements in a register,
// so long as the correct memory order is preserved. If we have a
// computation where all input values are provided by lxvd2x/xxswapd,
// all outputs are stored using xxswapd/lxvd2x, and all intermediate
// computations are lane-insensitive (independent of element order),
// then all the xxswapd instructions associated with the loads and
// stores may be removed without changing observable semantics.
//
// This pass uses standard equivalence class infrastructure to create
// maximal webs of computations fitting the above description. Each
// such web is then optimized by removing its unnecessary xxswapd
// instructions.
//
// There are some lane-sensitive operations for which we can still
// permit the optimization, provided we modify those operations
// accordingly. Such operations are identified as using "special
// handling" within this module.
//
//===---------------------------------------------------------------------===//
#include "PPCInstrInfo.h"
#include "PPC.h"
#include "PPCInstrBuilder.h"
#include "PPCTargetMachine.h"
#include "llvm/ADT/DenseMap.h"
#include "llvm/ADT/EquivalenceClasses.h"
#include "llvm/CodeGen/MachineFunctionPass.h"
#include "llvm/CodeGen/MachineInstrBuilder.h"
#include "llvm/CodeGen/MachineRegisterInfo.h"
#include "llvm/Support/Debug.h"
#include "llvm/Support/Format.h"
#include "llvm/Support/raw_ostream.h"
using namespace llvm;
#define DEBUG_TYPE "ppc-vsx-swaps"
namespace llvm {
void initializePPCVSXSwapRemovalPass(PassRegistry&);
}
namespace {
// A PPCVSXSwapEntry is created for each machine instruction that
// is relevant to a vector computation.
struct PPCVSXSwapEntry {
// Pointer to the instruction.
MachineInstr *VSEMI;
// Unique ID (position in the swap vector).
int VSEId;
// Attributes of this node.
unsigned int IsLoad : 1;
unsigned int IsStore : 1;
unsigned int IsSwap : 1;
unsigned int MentionsPhysVR : 1;
unsigned int IsSwappable : 1;
[PPC64LE] More improvements to VSX swap optimization This patch allows VSX swap optimization to succeed more frequently. Specifically, it is concerned with common code sequences that occur when copying a scalar floating-point value to a vector register. This patch currently handles cases where the floating-point value is already in a register, but does not yet handle loads (such as via an LXSDX scalar floating-point VSX load). That will be dealt with later. A typical case is when a scalar value comes in as a floating-point parameter. The value is copied into a virtual VSFRC register, and then a sequence of SUBREG_TO_REG and/or COPY operations will convert it to a full vector register of the class required by the context. If this vector register is then used as part of a lane-permuted computation, the original scalar value will be in the wrong lane. We can fix this by adding a swap operation following any widening SUBREG_TO_REG operation. Additional COPY operations may be needed around the swap operation in order to keep register assignment happy, but these are pro forma operations that will be removed by coalescing. If a scalar value is otherwise directly referenced in a computation (such as by one of the many XS* vector-scalar operations), we currently disable swap optimization. These operations are lane-sensitive by definition. A MentionsPartialVR flag is added for use in each swap table entry that mentions a scalar floating-point register without having special handling defined. A common idiom for PPC64LE is to convert a double-precision scalar to a vector by performing a splat operation. This ensures that the value can be referenced as V[0], as it would be for big endian, whereas just converting the scalar to a vector with a SUBREG_TO_REG operation leaves this value only in V[1]. A doubleword splat operation is one form of an XXPERMDI instruction, which takes one doubleword from a first operand and another doubleword from a second operand, with a two-bit selector operand indicating which doublewords are chosen. In the general case, an XXPERMDI can be permitted in a lane-swapped region provided that it is properly transformed to select the corresponding swapped values. This transformation is to reverse the order of the two input operands, and to reverse and complement the bits of the selector operand (derivation left as an exercise to the reader ;). A new test case that exercises the scalar-to-vector and generalized XXPERMDI transformations is added as CodeGen/PowerPC/swaps-le-5.ll. The patch also requires a change to CodeGen/PowerPC/swaps-le-3.ll to use CHECK-DAG instead of CHECK for two independent instructions that now appear in reverse order. There are two small unrelated changes that are added with this patch. First, the XXSLDWI instruction was incorrectly omitted from the list of lane-sensitive instructions; this is now fixed. Second, I observed that the same webs were being rejected over and over again for different reasons. Since it's sufficient to reject a web only once, I added a check for this to speed up the compilation time slightly. llvm-svn: 242081
2015-07-14 06:58:19 +08:00
unsigned int MentionsPartialVR : 1;
[PPC64LE] Remove unnecessary swaps from lane-insensitive vector computations This patch adds a new SSA MI pass that runs on little-endian PPC64 code with VSX enabled. Loads and stores of 4x32 and 2x64 vectors without alignment constraints are accomplished for little-endian using lxvd2x/xxswapd and xxswapd/stxvd2x. The existence of the additional xxswapd instructions hurts performance in comparison with big-endian code, but they are necessary in the general case to support correct semantics. However, the general case does not apply to most vector code. Many vector instructions are lane-insensitive; they do not "care" which lanes the parallel computations are performed within, provided that the resulting data is stored into the correct locations. Thus this pass looks for computations that perform only lane-insensitive operations, and remove the unnecessary swaps from loads and stores in such computations. Future improvements will allow computations using certain lane-sensitive operations to also be optimized in this manner, by modifying the lane-sensitive operations to account for the permuted order of the lanes. However, this patch only adds the infrastructure to permit this; no lane-sensitive operations are optimized at this time. This code is heavily exercised by the various vectorizing applications in the projects/test-suite tree. For the time being, I have only added one simple test case to demonstrate what the pass is doing. Although it is quite simple, it provides coverage for much of the code, including the special case handling of copies and subreg-to-reg operations feeding the swaps. I plan to add additional tests in the future as I fill in more of the "special handling" code. Two existing tests were affected, because they expected the swaps to be present, but they are now removed. llvm-svn: 235910
2015-04-28 03:57:34 +08:00
unsigned int SpecialHandling : 3;
unsigned int WebRejected : 1;
unsigned int WillRemove : 1;
};
enum SHValues {
SH_NONE = 0,
SH_EXTRACT,
SH_INSERT,
SH_NOSWAP_LD,
SH_NOSWAP_ST,
[PPC64LE] More improvements to VSX swap optimization This patch allows VSX swap optimization to succeed more frequently. Specifically, it is concerned with common code sequences that occur when copying a scalar floating-point value to a vector register. This patch currently handles cases where the floating-point value is already in a register, but does not yet handle loads (such as via an LXSDX scalar floating-point VSX load). That will be dealt with later. A typical case is when a scalar value comes in as a floating-point parameter. The value is copied into a virtual VSFRC register, and then a sequence of SUBREG_TO_REG and/or COPY operations will convert it to a full vector register of the class required by the context. If this vector register is then used as part of a lane-permuted computation, the original scalar value will be in the wrong lane. We can fix this by adding a swap operation following any widening SUBREG_TO_REG operation. Additional COPY operations may be needed around the swap operation in order to keep register assignment happy, but these are pro forma operations that will be removed by coalescing. If a scalar value is otherwise directly referenced in a computation (such as by one of the many XS* vector-scalar operations), we currently disable swap optimization. These operations are lane-sensitive by definition. A MentionsPartialVR flag is added for use in each swap table entry that mentions a scalar floating-point register without having special handling defined. A common idiom for PPC64LE is to convert a double-precision scalar to a vector by performing a splat operation. This ensures that the value can be referenced as V[0], as it would be for big endian, whereas just converting the scalar to a vector with a SUBREG_TO_REG operation leaves this value only in V[1]. A doubleword splat operation is one form of an XXPERMDI instruction, which takes one doubleword from a first operand and another doubleword from a second operand, with a two-bit selector operand indicating which doublewords are chosen. In the general case, an XXPERMDI can be permitted in a lane-swapped region provided that it is properly transformed to select the corresponding swapped values. This transformation is to reverse the order of the two input operands, and to reverse and complement the bits of the selector operand (derivation left as an exercise to the reader ;). A new test case that exercises the scalar-to-vector and generalized XXPERMDI transformations is added as CodeGen/PowerPC/swaps-le-5.ll. The patch also requires a change to CodeGen/PowerPC/swaps-le-3.ll to use CHECK-DAG instead of CHECK for two independent instructions that now appear in reverse order. There are two small unrelated changes that are added with this patch. First, the XXSLDWI instruction was incorrectly omitted from the list of lane-sensitive instructions; this is now fixed. Second, I observed that the same webs were being rejected over and over again for different reasons. Since it's sufficient to reject a web only once, I added a check for this to speed up the compilation time slightly. llvm-svn: 242081
2015-07-14 06:58:19 +08:00
SH_SPLAT,
SH_XXPERMDI,
[PPC64LE] More vector swap optimization TLC This makes one substantive change and a few stylistic changes to the VSX swap optimization pass. The substantive change is to permit LXSDX and LXSSPX instructions to participate in swap optimization computations. The previous change to insert a swap following a SUBREG_TO_REG widening operation makes this almost trivial. I experimented with also permitting STXSDX and STXSSPX instructions. This can be done using similar techniques: we could insert a swap prior to a narrowing COPY operation, and then permit these stores to participate. I prototyped this, but discovered that the pattern of a narrowing COPY followed by an STXSDX does not occur in any of our test-suite code. So instead, I added commentary indicating that this could be done. Other TLC: - I changed SH_COPYSCALAR to SH_COPYWIDEN to more clearly indicate the direction of the copy. - I factored the insertion of swap instructions into a separate function. Finally, I added a new test case to check that the scalar-to-vector loads are working properly with swap optimization. llvm-svn: 242838
2015-07-22 05:40:17 +08:00
SH_COPYWIDEN
[PPC64LE] Remove unnecessary swaps from lane-insensitive vector computations This patch adds a new SSA MI pass that runs on little-endian PPC64 code with VSX enabled. Loads and stores of 4x32 and 2x64 vectors without alignment constraints are accomplished for little-endian using lxvd2x/xxswapd and xxswapd/stxvd2x. The existence of the additional xxswapd instructions hurts performance in comparison with big-endian code, but they are necessary in the general case to support correct semantics. However, the general case does not apply to most vector code. Many vector instructions are lane-insensitive; they do not "care" which lanes the parallel computations are performed within, provided that the resulting data is stored into the correct locations. Thus this pass looks for computations that perform only lane-insensitive operations, and remove the unnecessary swaps from loads and stores in such computations. Future improvements will allow computations using certain lane-sensitive operations to also be optimized in this manner, by modifying the lane-sensitive operations to account for the permuted order of the lanes. However, this patch only adds the infrastructure to permit this; no lane-sensitive operations are optimized at this time. This code is heavily exercised by the various vectorizing applications in the projects/test-suite tree. For the time being, I have only added one simple test case to demonstrate what the pass is doing. Although it is quite simple, it provides coverage for much of the code, including the special case handling of copies and subreg-to-reg operations feeding the swaps. I plan to add additional tests in the future as I fill in more of the "special handling" code. Two existing tests were affected, because they expected the swaps to be present, but they are now removed. llvm-svn: 235910
2015-04-28 03:57:34 +08:00
};
struct PPCVSXSwapRemoval : public MachineFunctionPass {
static char ID;
const PPCInstrInfo *TII;
MachineFunction *MF;
MachineRegisterInfo *MRI;
// Swap entries are allocated in a vector for better performance.
std::vector<PPCVSXSwapEntry> SwapVector;
// A mapping is maintained between machine instructions and
// their swap entries. The key is the address of the MI.
DenseMap<MachineInstr*, int> SwapMap;
// Equivalence classes are used to gather webs of related computation.
// Swap entries are represented by their VSEId fields.
EquivalenceClasses<int> *EC;
PPCVSXSwapRemoval() : MachineFunctionPass(ID) {
initializePPCVSXSwapRemovalPass(*PassRegistry::getPassRegistry());
}
private:
// Initialize data structures.
void initialize(MachineFunction &MFParm);
// Walk the machine instructions to gather vector usage information.
// Return true iff vector mentions are present.
bool gatherVectorInstructions();
// Add an entry to the swap vector and swap map.
int addSwapEntry(MachineInstr *MI, PPCVSXSwapEntry &SwapEntry);
// Hunt backwards through COPY and SUBREG_TO_REG chains for a
// source register. VecIdx indicates the swap vector entry to
// mark as mentioning a physical register if the search leads
// to one.
unsigned lookThruCopyLike(unsigned SrcReg, unsigned VecIdx);
// Generate equivalence classes for related computations (webs).
void formWebs();
// Analyze webs and determine those that cannot be optimized.
void recordUnoptimizableWebs();
// Record which swap instructions can be safely removed.
void markSwapsForRemoval();
// Remove swaps and update other instructions requiring special
// handling. Return true iff any changes are made.
bool removeSwaps();
[PPC64LE] More vector swap optimization TLC This makes one substantive change and a few stylistic changes to the VSX swap optimization pass. The substantive change is to permit LXSDX and LXSSPX instructions to participate in swap optimization computations. The previous change to insert a swap following a SUBREG_TO_REG widening operation makes this almost trivial. I experimented with also permitting STXSDX and STXSSPX instructions. This can be done using similar techniques: we could insert a swap prior to a narrowing COPY operation, and then permit these stores to participate. I prototyped this, but discovered that the pattern of a narrowing COPY followed by an STXSDX does not occur in any of our test-suite code. So instead, I added commentary indicating that this could be done. Other TLC: - I changed SH_COPYSCALAR to SH_COPYWIDEN to more clearly indicate the direction of the copy. - I factored the insertion of swap instructions into a separate function. Finally, I added a new test case to check that the scalar-to-vector loads are working properly with swap optimization. llvm-svn: 242838
2015-07-22 05:40:17 +08:00
// Insert a swap instruction from SrcReg to DstReg at the given
// InsertPoint.
void insertSwap(MachineInstr *MI, MachineBasicBlock::iterator InsertPoint,
unsigned DstReg, unsigned SrcReg);
[PPC64LE] Remove unnecessary swaps from lane-insensitive vector computations This patch adds a new SSA MI pass that runs on little-endian PPC64 code with VSX enabled. Loads and stores of 4x32 and 2x64 vectors without alignment constraints are accomplished for little-endian using lxvd2x/xxswapd and xxswapd/stxvd2x. The existence of the additional xxswapd instructions hurts performance in comparison with big-endian code, but they are necessary in the general case to support correct semantics. However, the general case does not apply to most vector code. Many vector instructions are lane-insensitive; they do not "care" which lanes the parallel computations are performed within, provided that the resulting data is stored into the correct locations. Thus this pass looks for computations that perform only lane-insensitive operations, and remove the unnecessary swaps from loads and stores in such computations. Future improvements will allow computations using certain lane-sensitive operations to also be optimized in this manner, by modifying the lane-sensitive operations to account for the permuted order of the lanes. However, this patch only adds the infrastructure to permit this; no lane-sensitive operations are optimized at this time. This code is heavily exercised by the various vectorizing applications in the projects/test-suite tree. For the time being, I have only added one simple test case to demonstrate what the pass is doing. Although it is quite simple, it provides coverage for much of the code, including the special case handling of copies and subreg-to-reg operations feeding the swaps. I plan to add additional tests in the future as I fill in more of the "special handling" code. Two existing tests were affected, because they expected the swaps to be present, but they are now removed. llvm-svn: 235910
2015-04-28 03:57:34 +08:00
// Update instructions requiring special handling.
void handleSpecialSwappables(int EntryIdx);
// Dump a description of the entries in the swap vector.
void dumpSwapVector();
// Return true iff the given register is in the given class.
bool isRegInClass(unsigned Reg, const TargetRegisterClass *RC) {
if (TargetRegisterInfo::isVirtualRegister(Reg))
return RC->hasSubClassEq(MRI->getRegClass(Reg));
Refactor: Simplify boolean conditional return statements in lib/Target/PowerPC Summary: Use clang-tidy to simplify boolean conditional return statements Reviewers: uweigand, rafael, wschmidt Subscribers: craig.topper, llvm-commits Patch by Richard Thomson! Differential Revision: http://reviews.llvm.org/D9984 llvm-svn: 256493
2015-12-28 21:38:42 +08:00
return RC->contains(Reg);
[PPC64LE] Remove unnecessary swaps from lane-insensitive vector computations This patch adds a new SSA MI pass that runs on little-endian PPC64 code with VSX enabled. Loads and stores of 4x32 and 2x64 vectors without alignment constraints are accomplished for little-endian using lxvd2x/xxswapd and xxswapd/stxvd2x. The existence of the additional xxswapd instructions hurts performance in comparison with big-endian code, but they are necessary in the general case to support correct semantics. However, the general case does not apply to most vector code. Many vector instructions are lane-insensitive; they do not "care" which lanes the parallel computations are performed within, provided that the resulting data is stored into the correct locations. Thus this pass looks for computations that perform only lane-insensitive operations, and remove the unnecessary swaps from loads and stores in such computations. Future improvements will allow computations using certain lane-sensitive operations to also be optimized in this manner, by modifying the lane-sensitive operations to account for the permuted order of the lanes. However, this patch only adds the infrastructure to permit this; no lane-sensitive operations are optimized at this time. This code is heavily exercised by the various vectorizing applications in the projects/test-suite tree. For the time being, I have only added one simple test case to demonstrate what the pass is doing. Although it is quite simple, it provides coverage for much of the code, including the special case handling of copies and subreg-to-reg operations feeding the swaps. I plan to add additional tests in the future as I fill in more of the "special handling" code. Two existing tests were affected, because they expected the swaps to be present, but they are now removed. llvm-svn: 235910
2015-04-28 03:57:34 +08:00
}
// Return true iff the given register is a full vector register.
bool isVecReg(unsigned Reg) {
return (isRegInClass(Reg, &PPC::VSRCRegClass) ||
isRegInClass(Reg, &PPC::VRRCRegClass));
}
[PPC64LE] More improvements to VSX swap optimization This patch allows VSX swap optimization to succeed more frequently. Specifically, it is concerned with common code sequences that occur when copying a scalar floating-point value to a vector register. This patch currently handles cases where the floating-point value is already in a register, but does not yet handle loads (such as via an LXSDX scalar floating-point VSX load). That will be dealt with later. A typical case is when a scalar value comes in as a floating-point parameter. The value is copied into a virtual VSFRC register, and then a sequence of SUBREG_TO_REG and/or COPY operations will convert it to a full vector register of the class required by the context. If this vector register is then used as part of a lane-permuted computation, the original scalar value will be in the wrong lane. We can fix this by adding a swap operation following any widening SUBREG_TO_REG operation. Additional COPY operations may be needed around the swap operation in order to keep register assignment happy, but these are pro forma operations that will be removed by coalescing. If a scalar value is otherwise directly referenced in a computation (such as by one of the many XS* vector-scalar operations), we currently disable swap optimization. These operations are lane-sensitive by definition. A MentionsPartialVR flag is added for use in each swap table entry that mentions a scalar floating-point register without having special handling defined. A common idiom for PPC64LE is to convert a double-precision scalar to a vector by performing a splat operation. This ensures that the value can be referenced as V[0], as it would be for big endian, whereas just converting the scalar to a vector with a SUBREG_TO_REG operation leaves this value only in V[1]. A doubleword splat operation is one form of an XXPERMDI instruction, which takes one doubleword from a first operand and another doubleword from a second operand, with a two-bit selector operand indicating which doublewords are chosen. In the general case, an XXPERMDI can be permitted in a lane-swapped region provided that it is properly transformed to select the corresponding swapped values. This transformation is to reverse the order of the two input operands, and to reverse and complement the bits of the selector operand (derivation left as an exercise to the reader ;). A new test case that exercises the scalar-to-vector and generalized XXPERMDI transformations is added as CodeGen/PowerPC/swaps-le-5.ll. The patch also requires a change to CodeGen/PowerPC/swaps-le-3.ll to use CHECK-DAG instead of CHECK for two independent instructions that now appear in reverse order. There are two small unrelated changes that are added with this patch. First, the XXSLDWI instruction was incorrectly omitted from the list of lane-sensitive instructions; this is now fixed. Second, I observed that the same webs were being rejected over and over again for different reasons. Since it's sufficient to reject a web only once, I added a check for this to speed up the compilation time slightly. llvm-svn: 242081
2015-07-14 06:58:19 +08:00
// Return true iff the given register is a partial vector register.
bool isScalarVecReg(unsigned Reg) {
return (isRegInClass(Reg, &PPC::VSFRCRegClass) ||
isRegInClass(Reg, &PPC::VSSRCRegClass));
}
// Return true iff the given register mentions all or part of a
// vector register. Also sets Partial to true if the mention
// is for just the floating-point register overlap of the register.
bool isAnyVecReg(unsigned Reg, bool &Partial) {
if (isScalarVecReg(Reg))
Partial = true;
return isScalarVecReg(Reg) || isVecReg(Reg);
}
[PPC64LE] Remove unnecessary swaps from lane-insensitive vector computations This patch adds a new SSA MI pass that runs on little-endian PPC64 code with VSX enabled. Loads and stores of 4x32 and 2x64 vectors without alignment constraints are accomplished for little-endian using lxvd2x/xxswapd and xxswapd/stxvd2x. The existence of the additional xxswapd instructions hurts performance in comparison with big-endian code, but they are necessary in the general case to support correct semantics. However, the general case does not apply to most vector code. Many vector instructions are lane-insensitive; they do not "care" which lanes the parallel computations are performed within, provided that the resulting data is stored into the correct locations. Thus this pass looks for computations that perform only lane-insensitive operations, and remove the unnecessary swaps from loads and stores in such computations. Future improvements will allow computations using certain lane-sensitive operations to also be optimized in this manner, by modifying the lane-sensitive operations to account for the permuted order of the lanes. However, this patch only adds the infrastructure to permit this; no lane-sensitive operations are optimized at this time. This code is heavily exercised by the various vectorizing applications in the projects/test-suite tree. For the time being, I have only added one simple test case to demonstrate what the pass is doing. Although it is quite simple, it provides coverage for much of the code, including the special case handling of copies and subreg-to-reg operations feeding the swaps. I plan to add additional tests in the future as I fill in more of the "special handling" code. Two existing tests were affected, because they expected the swaps to be present, but they are now removed. llvm-svn: 235910
2015-04-28 03:57:34 +08:00
public:
// Main entry point for this pass.
bool runOnMachineFunction(MachineFunction &MF) override {
// If we don't have VSX on the subtarget, don't do anything.
const PPCSubtarget &STI = MF.getSubtarget<PPCSubtarget>();
if (!STI.hasVSX())
return false;
bool Changed = false;
initialize(MF);
if (gatherVectorInstructions()) {
formWebs();
recordUnoptimizableWebs();
markSwapsForRemoval();
Changed = removeSwaps();
}
// FIXME: See the allocation of EC in initialize().
delete EC;
return Changed;
}
};
// Initialize data structures for this pass. In particular, clear the
// swap vector and allocate the equivalence class mapping before
// processing each function.
void PPCVSXSwapRemoval::initialize(MachineFunction &MFParm) {
MF = &MFParm;
MRI = &MF->getRegInfo();
[PPC64LE] Properly initialize instr-info in PPCVSXSwapRemoval pass Replace some hacky code with the proper way to get at this data. No functional change. llvm-svn: 251848
2015-11-03 06:43:57 +08:00
TII = MF->getSubtarget<PPCSubtarget>().getInstrInfo();
[PPC64LE] Remove unnecessary swaps from lane-insensitive vector computations This patch adds a new SSA MI pass that runs on little-endian PPC64 code with VSX enabled. Loads and stores of 4x32 and 2x64 vectors without alignment constraints are accomplished for little-endian using lxvd2x/xxswapd and xxswapd/stxvd2x. The existence of the additional xxswapd instructions hurts performance in comparison with big-endian code, but they are necessary in the general case to support correct semantics. However, the general case does not apply to most vector code. Many vector instructions are lane-insensitive; they do not "care" which lanes the parallel computations are performed within, provided that the resulting data is stored into the correct locations. Thus this pass looks for computations that perform only lane-insensitive operations, and remove the unnecessary swaps from loads and stores in such computations. Future improvements will allow computations using certain lane-sensitive operations to also be optimized in this manner, by modifying the lane-sensitive operations to account for the permuted order of the lanes. However, this patch only adds the infrastructure to permit this; no lane-sensitive operations are optimized at this time. This code is heavily exercised by the various vectorizing applications in the projects/test-suite tree. For the time being, I have only added one simple test case to demonstrate what the pass is doing. Although it is quite simple, it provides coverage for much of the code, including the special case handling of copies and subreg-to-reg operations feeding the swaps. I plan to add additional tests in the future as I fill in more of the "special handling" code. Two existing tests were affected, because they expected the swaps to be present, but they are now removed. llvm-svn: 235910
2015-04-28 03:57:34 +08:00
// An initial vector size of 256 appears to work well in practice.
// Small/medium functions with vector content tend not to incur a
// reallocation at this size. Three of the vector tests in
// projects/test-suite reallocate, which seems like a reasonable rate.
const int InitialVectorSize(256);
SwapVector.clear();
SwapVector.reserve(InitialVectorSize);
// FIXME: Currently we allocate EC each time because we don't have
// access to the set representation on which to call clear(). Should
// consider adding a clear() method to the EquivalenceClasses class.
EC = new EquivalenceClasses<int>;
}
// Create an entry in the swap vector for each instruction that mentions
// a full vector register, recording various characteristics of the
// instructions there.
bool PPCVSXSwapRemoval::gatherVectorInstructions() {
bool RelevantFunction = false;
for (MachineBasicBlock &MBB : *MF) {
for (MachineInstr &MI : MBB) {
[PPC64LE] Fix PR24546 - Swap optimization and debug values This patch fixes PR24546, which demonstrates a segfault during the VSX swap removal pass. The problem is that debug value instructions were not excluded from the list of instructions to be analyzed for webs of related computation. I've added the test case from the PR as a crash test in test/CodeGen/PowerPC. llvm-svn: 245862
2015-08-25 03:27:27 +08:00
if (MI.isDebugValue())
continue;
[PPC64LE] Remove unnecessary swaps from lane-insensitive vector computations This patch adds a new SSA MI pass that runs on little-endian PPC64 code with VSX enabled. Loads and stores of 4x32 and 2x64 vectors without alignment constraints are accomplished for little-endian using lxvd2x/xxswapd and xxswapd/stxvd2x. The existence of the additional xxswapd instructions hurts performance in comparison with big-endian code, but they are necessary in the general case to support correct semantics. However, the general case does not apply to most vector code. Many vector instructions are lane-insensitive; they do not "care" which lanes the parallel computations are performed within, provided that the resulting data is stored into the correct locations. Thus this pass looks for computations that perform only lane-insensitive operations, and remove the unnecessary swaps from loads and stores in such computations. Future improvements will allow computations using certain lane-sensitive operations to also be optimized in this manner, by modifying the lane-sensitive operations to account for the permuted order of the lanes. However, this patch only adds the infrastructure to permit this; no lane-sensitive operations are optimized at this time. This code is heavily exercised by the various vectorizing applications in the projects/test-suite tree. For the time being, I have only added one simple test case to demonstrate what the pass is doing. Although it is quite simple, it provides coverage for much of the code, including the special case handling of copies and subreg-to-reg operations feeding the swaps. I plan to add additional tests in the future as I fill in more of the "special handling" code. Two existing tests were affected, because they expected the swaps to be present, but they are now removed. llvm-svn: 235910
2015-04-28 03:57:34 +08:00
bool RelevantInstr = false;
[PPC64LE] More improvements to VSX swap optimization This patch allows VSX swap optimization to succeed more frequently. Specifically, it is concerned with common code sequences that occur when copying a scalar floating-point value to a vector register. This patch currently handles cases where the floating-point value is already in a register, but does not yet handle loads (such as via an LXSDX scalar floating-point VSX load). That will be dealt with later. A typical case is when a scalar value comes in as a floating-point parameter. The value is copied into a virtual VSFRC register, and then a sequence of SUBREG_TO_REG and/or COPY operations will convert it to a full vector register of the class required by the context. If this vector register is then used as part of a lane-permuted computation, the original scalar value will be in the wrong lane. We can fix this by adding a swap operation following any widening SUBREG_TO_REG operation. Additional COPY operations may be needed around the swap operation in order to keep register assignment happy, but these are pro forma operations that will be removed by coalescing. If a scalar value is otherwise directly referenced in a computation (such as by one of the many XS* vector-scalar operations), we currently disable swap optimization. These operations are lane-sensitive by definition. A MentionsPartialVR flag is added for use in each swap table entry that mentions a scalar floating-point register without having special handling defined. A common idiom for PPC64LE is to convert a double-precision scalar to a vector by performing a splat operation. This ensures that the value can be referenced as V[0], as it would be for big endian, whereas just converting the scalar to a vector with a SUBREG_TO_REG operation leaves this value only in V[1]. A doubleword splat operation is one form of an XXPERMDI instruction, which takes one doubleword from a first operand and another doubleword from a second operand, with a two-bit selector operand indicating which doublewords are chosen. In the general case, an XXPERMDI can be permitted in a lane-swapped region provided that it is properly transformed to select the corresponding swapped values. This transformation is to reverse the order of the two input operands, and to reverse and complement the bits of the selector operand (derivation left as an exercise to the reader ;). A new test case that exercises the scalar-to-vector and generalized XXPERMDI transformations is added as CodeGen/PowerPC/swaps-le-5.ll. The patch also requires a change to CodeGen/PowerPC/swaps-le-3.ll to use CHECK-DAG instead of CHECK for two independent instructions that now appear in reverse order. There are two small unrelated changes that are added with this patch. First, the XXSLDWI instruction was incorrectly omitted from the list of lane-sensitive instructions; this is now fixed. Second, I observed that the same webs were being rejected over and over again for different reasons. Since it's sufficient to reject a web only once, I added a check for this to speed up the compilation time slightly. llvm-svn: 242081
2015-07-14 06:58:19 +08:00
bool Partial = false;
[PPC64LE] Remove unnecessary swaps from lane-insensitive vector computations This patch adds a new SSA MI pass that runs on little-endian PPC64 code with VSX enabled. Loads and stores of 4x32 and 2x64 vectors without alignment constraints are accomplished for little-endian using lxvd2x/xxswapd and xxswapd/stxvd2x. The existence of the additional xxswapd instructions hurts performance in comparison with big-endian code, but they are necessary in the general case to support correct semantics. However, the general case does not apply to most vector code. Many vector instructions are lane-insensitive; they do not "care" which lanes the parallel computations are performed within, provided that the resulting data is stored into the correct locations. Thus this pass looks for computations that perform only lane-insensitive operations, and remove the unnecessary swaps from loads and stores in such computations. Future improvements will allow computations using certain lane-sensitive operations to also be optimized in this manner, by modifying the lane-sensitive operations to account for the permuted order of the lanes. However, this patch only adds the infrastructure to permit this; no lane-sensitive operations are optimized at this time. This code is heavily exercised by the various vectorizing applications in the projects/test-suite tree. For the time being, I have only added one simple test case to demonstrate what the pass is doing. Although it is quite simple, it provides coverage for much of the code, including the special case handling of copies and subreg-to-reg operations feeding the swaps. I plan to add additional tests in the future as I fill in more of the "special handling" code. Two existing tests were affected, because they expected the swaps to be present, but they are now removed. llvm-svn: 235910
2015-04-28 03:57:34 +08:00
for (const MachineOperand &MO : MI.operands()) {
if (!MO.isReg())
continue;
unsigned Reg = MO.getReg();
[PPC64LE] More improvements to VSX swap optimization This patch allows VSX swap optimization to succeed more frequently. Specifically, it is concerned with common code sequences that occur when copying a scalar floating-point value to a vector register. This patch currently handles cases where the floating-point value is already in a register, but does not yet handle loads (such as via an LXSDX scalar floating-point VSX load). That will be dealt with later. A typical case is when a scalar value comes in as a floating-point parameter. The value is copied into a virtual VSFRC register, and then a sequence of SUBREG_TO_REG and/or COPY operations will convert it to a full vector register of the class required by the context. If this vector register is then used as part of a lane-permuted computation, the original scalar value will be in the wrong lane. We can fix this by adding a swap operation following any widening SUBREG_TO_REG operation. Additional COPY operations may be needed around the swap operation in order to keep register assignment happy, but these are pro forma operations that will be removed by coalescing. If a scalar value is otherwise directly referenced in a computation (such as by one of the many XS* vector-scalar operations), we currently disable swap optimization. These operations are lane-sensitive by definition. A MentionsPartialVR flag is added for use in each swap table entry that mentions a scalar floating-point register without having special handling defined. A common idiom for PPC64LE is to convert a double-precision scalar to a vector by performing a splat operation. This ensures that the value can be referenced as V[0], as it would be for big endian, whereas just converting the scalar to a vector with a SUBREG_TO_REG operation leaves this value only in V[1]. A doubleword splat operation is one form of an XXPERMDI instruction, which takes one doubleword from a first operand and another doubleword from a second operand, with a two-bit selector operand indicating which doublewords are chosen. In the general case, an XXPERMDI can be permitted in a lane-swapped region provided that it is properly transformed to select the corresponding swapped values. This transformation is to reverse the order of the two input operands, and to reverse and complement the bits of the selector operand (derivation left as an exercise to the reader ;). A new test case that exercises the scalar-to-vector and generalized XXPERMDI transformations is added as CodeGen/PowerPC/swaps-le-5.ll. The patch also requires a change to CodeGen/PowerPC/swaps-le-3.ll to use CHECK-DAG instead of CHECK for two independent instructions that now appear in reverse order. There are two small unrelated changes that are added with this patch. First, the XXSLDWI instruction was incorrectly omitted from the list of lane-sensitive instructions; this is now fixed. Second, I observed that the same webs were being rejected over and over again for different reasons. Since it's sufficient to reject a web only once, I added a check for this to speed up the compilation time slightly. llvm-svn: 242081
2015-07-14 06:58:19 +08:00
if (isAnyVecReg(Reg, Partial)) {
[PPC64LE] Remove unnecessary swaps from lane-insensitive vector computations This patch adds a new SSA MI pass that runs on little-endian PPC64 code with VSX enabled. Loads and stores of 4x32 and 2x64 vectors without alignment constraints are accomplished for little-endian using lxvd2x/xxswapd and xxswapd/stxvd2x. The existence of the additional xxswapd instructions hurts performance in comparison with big-endian code, but they are necessary in the general case to support correct semantics. However, the general case does not apply to most vector code. Many vector instructions are lane-insensitive; they do not "care" which lanes the parallel computations are performed within, provided that the resulting data is stored into the correct locations. Thus this pass looks for computations that perform only lane-insensitive operations, and remove the unnecessary swaps from loads and stores in such computations. Future improvements will allow computations using certain lane-sensitive operations to also be optimized in this manner, by modifying the lane-sensitive operations to account for the permuted order of the lanes. However, this patch only adds the infrastructure to permit this; no lane-sensitive operations are optimized at this time. This code is heavily exercised by the various vectorizing applications in the projects/test-suite tree. For the time being, I have only added one simple test case to demonstrate what the pass is doing. Although it is quite simple, it provides coverage for much of the code, including the special case handling of copies and subreg-to-reg operations feeding the swaps. I plan to add additional tests in the future as I fill in more of the "special handling" code. Two existing tests were affected, because they expected the swaps to be present, but they are now removed. llvm-svn: 235910
2015-04-28 03:57:34 +08:00
RelevantInstr = true;
break;
}
}
if (!RelevantInstr)
continue;
RelevantFunction = true;
// Create a SwapEntry initialized to zeros, then fill in the
// instruction and ID fields before pushing it to the back
// of the swap vector.
PPCVSXSwapEntry SwapEntry{};
int VecIdx = addSwapEntry(&MI, SwapEntry);
switch(MI.getOpcode()) {
default:
// Unless noted otherwise, an instruction is considered
// safe for the optimization. There are a large number of
// such true-SIMD instructions (all vector math, logical,
[PPC64LE] More improvements to VSX swap optimization This patch allows VSX swap optimization to succeed more frequently. Specifically, it is concerned with common code sequences that occur when copying a scalar floating-point value to a vector register. This patch currently handles cases where the floating-point value is already in a register, but does not yet handle loads (such as via an LXSDX scalar floating-point VSX load). That will be dealt with later. A typical case is when a scalar value comes in as a floating-point parameter. The value is copied into a virtual VSFRC register, and then a sequence of SUBREG_TO_REG and/or COPY operations will convert it to a full vector register of the class required by the context. If this vector register is then used as part of a lane-permuted computation, the original scalar value will be in the wrong lane. We can fix this by adding a swap operation following any widening SUBREG_TO_REG operation. Additional COPY operations may be needed around the swap operation in order to keep register assignment happy, but these are pro forma operations that will be removed by coalescing. If a scalar value is otherwise directly referenced in a computation (such as by one of the many XS* vector-scalar operations), we currently disable swap optimization. These operations are lane-sensitive by definition. A MentionsPartialVR flag is added for use in each swap table entry that mentions a scalar floating-point register without having special handling defined. A common idiom for PPC64LE is to convert a double-precision scalar to a vector by performing a splat operation. This ensures that the value can be referenced as V[0], as it would be for big endian, whereas just converting the scalar to a vector with a SUBREG_TO_REG operation leaves this value only in V[1]. A doubleword splat operation is one form of an XXPERMDI instruction, which takes one doubleword from a first operand and another doubleword from a second operand, with a two-bit selector operand indicating which doublewords are chosen. In the general case, an XXPERMDI can be permitted in a lane-swapped region provided that it is properly transformed to select the corresponding swapped values. This transformation is to reverse the order of the two input operands, and to reverse and complement the bits of the selector operand (derivation left as an exercise to the reader ;). A new test case that exercises the scalar-to-vector and generalized XXPERMDI transformations is added as CodeGen/PowerPC/swaps-le-5.ll. The patch also requires a change to CodeGen/PowerPC/swaps-le-3.ll to use CHECK-DAG instead of CHECK for two independent instructions that now appear in reverse order. There are two small unrelated changes that are added with this patch. First, the XXSLDWI instruction was incorrectly omitted from the list of lane-sensitive instructions; this is now fixed. Second, I observed that the same webs were being rejected over and over again for different reasons. Since it's sufficient to reject a web only once, I added a check for this to speed up the compilation time slightly. llvm-svn: 242081
2015-07-14 06:58:19 +08:00
// select, compare, etc.). However, if the instruction
// mentions a partial vector register and does not have
// special handling defined, it is not swappable.
if (Partial)
SwapVector[VecIdx].MentionsPartialVR = 1;
else
SwapVector[VecIdx].IsSwappable = 1;
[PPC64LE] Remove unnecessary swaps from lane-insensitive vector computations This patch adds a new SSA MI pass that runs on little-endian PPC64 code with VSX enabled. Loads and stores of 4x32 and 2x64 vectors without alignment constraints are accomplished for little-endian using lxvd2x/xxswapd and xxswapd/stxvd2x. The existence of the additional xxswapd instructions hurts performance in comparison with big-endian code, but they are necessary in the general case to support correct semantics. However, the general case does not apply to most vector code. Many vector instructions are lane-insensitive; they do not "care" which lanes the parallel computations are performed within, provided that the resulting data is stored into the correct locations. Thus this pass looks for computations that perform only lane-insensitive operations, and remove the unnecessary swaps from loads and stores in such computations. Future improvements will allow computations using certain lane-sensitive operations to also be optimized in this manner, by modifying the lane-sensitive operations to account for the permuted order of the lanes. However, this patch only adds the infrastructure to permit this; no lane-sensitive operations are optimized at this time. This code is heavily exercised by the various vectorizing applications in the projects/test-suite tree. For the time being, I have only added one simple test case to demonstrate what the pass is doing. Although it is quite simple, it provides coverage for much of the code, including the special case handling of copies and subreg-to-reg operations feeding the swaps. I plan to add additional tests in the future as I fill in more of the "special handling" code. Two existing tests were affected, because they expected the swaps to be present, but they are now removed. llvm-svn: 235910
2015-04-28 03:57:34 +08:00
break;
[PPC64LE] Teach swap optimization about the doubleword splat idiom With a previous patch, the VSX swap optimization is able to recognize the doubleword load-splat idiom that can be implemented using lxvdsx. However, that does not cover a doubleword splat where the source is a register. We can implement this using xxspltd (a special form of xxpermdi). This patch teaches the swap optimization pass about this idiom. As a prerequisite, it also permits swap optimization to succeed for all forms of SUBREG_TO_REG. Previously we were conservative and only allowed SUBREG_TO_REG when it copied a full register. However, on reflection any form of SUBREG_TO_REG is safe in and of itself, so long as an unsafe operation is not performed on its result. In particular, a widening SUBREG_TO_REG often occurs as an input to a doubleword splat idiom, particularly in auto-vectorized code. The doubleword splat idiom is an XXPERMDI operation where both source registers are identical, and the selection mask is either 0 (splat the first element) or 3 (splat the second element). To determine whether the registers are identical, we use the existing mechanism for looking through "copy-like" operations. That mechanism has a side effect of marking the XXPERMDI operation as using a physical register, which would invalidate its presence in a swap-optimized region. This is correct for the form of XXPERMDI that performs a swap and hence would be removed, but is not what we want for a doubleword-splat variety of XXPERMDI. Therefore we reset the physical-register flag on the XXPERMDI when it represents a splat. A simple test case is added to verify that we generate the splat and that we also remove the xxswapd instructions that would otherwise be associated with the load and store of another operand. llvm-svn: 241285
2015-07-03 01:03:06 +08:00
case PPC::XXPERMDI: {
[PPC64LE] Remove unnecessary swaps from lane-insensitive vector computations This patch adds a new SSA MI pass that runs on little-endian PPC64 code with VSX enabled. Loads and stores of 4x32 and 2x64 vectors without alignment constraints are accomplished for little-endian using lxvd2x/xxswapd and xxswapd/stxvd2x. The existence of the additional xxswapd instructions hurts performance in comparison with big-endian code, but they are necessary in the general case to support correct semantics. However, the general case does not apply to most vector code. Many vector instructions are lane-insensitive; they do not "care" which lanes the parallel computations are performed within, provided that the resulting data is stored into the correct locations. Thus this pass looks for computations that perform only lane-insensitive operations, and remove the unnecessary swaps from loads and stores in such computations. Future improvements will allow computations using certain lane-sensitive operations to also be optimized in this manner, by modifying the lane-sensitive operations to account for the permuted order of the lanes. However, this patch only adds the infrastructure to permit this; no lane-sensitive operations are optimized at this time. This code is heavily exercised by the various vectorizing applications in the projects/test-suite tree. For the time being, I have only added one simple test case to demonstrate what the pass is doing. Although it is quite simple, it provides coverage for much of the code, including the special case handling of copies and subreg-to-reg operations feeding the swaps. I plan to add additional tests in the future as I fill in more of the "special handling" code. Two existing tests were affected, because they expected the swaps to be present, but they are now removed. llvm-svn: 235910
2015-04-28 03:57:34 +08:00
// This is a swap if it is of the form XXPERMDI t, s, s, 2.
// Unfortunately, MachineCSE ignores COPY and SUBREG_TO_REG, so we
// can also see XXPERMDI t, SUBREG_TO_REG(s), SUBREG_TO_REG(s), 2,
// for example. We have to look through chains of COPY and
// SUBREG_TO_REG to find the real source value for comparison.
// If the real source value is a physical register, then mark the
// XXPERMDI as mentioning a physical register.
[PPC64LE] Teach swap optimization about the doubleword splat idiom With a previous patch, the VSX swap optimization is able to recognize the doubleword load-splat idiom that can be implemented using lxvdsx. However, that does not cover a doubleword splat where the source is a register. We can implement this using xxspltd (a special form of xxpermdi). This patch teaches the swap optimization pass about this idiom. As a prerequisite, it also permits swap optimization to succeed for all forms of SUBREG_TO_REG. Previously we were conservative and only allowed SUBREG_TO_REG when it copied a full register. However, on reflection any form of SUBREG_TO_REG is safe in and of itself, so long as an unsafe operation is not performed on its result. In particular, a widening SUBREG_TO_REG often occurs as an input to a doubleword splat idiom, particularly in auto-vectorized code. The doubleword splat idiom is an XXPERMDI operation where both source registers are identical, and the selection mask is either 0 (splat the first element) or 3 (splat the second element). To determine whether the registers are identical, we use the existing mechanism for looking through "copy-like" operations. That mechanism has a side effect of marking the XXPERMDI operation as using a physical register, which would invalidate its presence in a swap-optimized region. This is correct for the form of XXPERMDI that performs a swap and hence would be removed, but is not what we want for a doubleword-splat variety of XXPERMDI. Therefore we reset the physical-register flag on the XXPERMDI when it represents a splat. A simple test case is added to verify that we generate the splat and that we also remove the xxswapd instructions that would otherwise be associated with the load and store of another operand. llvm-svn: 241285
2015-07-03 01:03:06 +08:00
int immed = MI.getOperand(3).getImm();
if (immed == 2) {
[PPC64LE] Remove unnecessary swaps from lane-insensitive vector computations This patch adds a new SSA MI pass that runs on little-endian PPC64 code with VSX enabled. Loads and stores of 4x32 and 2x64 vectors without alignment constraints are accomplished for little-endian using lxvd2x/xxswapd and xxswapd/stxvd2x. The existence of the additional xxswapd instructions hurts performance in comparison with big-endian code, but they are necessary in the general case to support correct semantics. However, the general case does not apply to most vector code. Many vector instructions are lane-insensitive; they do not "care" which lanes the parallel computations are performed within, provided that the resulting data is stored into the correct locations. Thus this pass looks for computations that perform only lane-insensitive operations, and remove the unnecessary swaps from loads and stores in such computations. Future improvements will allow computations using certain lane-sensitive operations to also be optimized in this manner, by modifying the lane-sensitive operations to account for the permuted order of the lanes. However, this patch only adds the infrastructure to permit this; no lane-sensitive operations are optimized at this time. This code is heavily exercised by the various vectorizing applications in the projects/test-suite tree. For the time being, I have only added one simple test case to demonstrate what the pass is doing. Although it is quite simple, it provides coverage for much of the code, including the special case handling of copies and subreg-to-reg operations feeding the swaps. I plan to add additional tests in the future as I fill in more of the "special handling" code. Two existing tests were affected, because they expected the swaps to be present, but they are now removed. llvm-svn: 235910
2015-04-28 03:57:34 +08:00
unsigned trueReg1 = lookThruCopyLike(MI.getOperand(1).getReg(),
VecIdx);
unsigned trueReg2 = lookThruCopyLike(MI.getOperand(2).getReg(),
VecIdx);
if (trueReg1 == trueReg2)
SwapVector[VecIdx].IsSwap = 1;
[PPC64LE] More improvements to VSX swap optimization This patch allows VSX swap optimization to succeed more frequently. Specifically, it is concerned with common code sequences that occur when copying a scalar floating-point value to a vector register. This patch currently handles cases where the floating-point value is already in a register, but does not yet handle loads (such as via an LXSDX scalar floating-point VSX load). That will be dealt with later. A typical case is when a scalar value comes in as a floating-point parameter. The value is copied into a virtual VSFRC register, and then a sequence of SUBREG_TO_REG and/or COPY operations will convert it to a full vector register of the class required by the context. If this vector register is then used as part of a lane-permuted computation, the original scalar value will be in the wrong lane. We can fix this by adding a swap operation following any widening SUBREG_TO_REG operation. Additional COPY operations may be needed around the swap operation in order to keep register assignment happy, but these are pro forma operations that will be removed by coalescing. If a scalar value is otherwise directly referenced in a computation (such as by one of the many XS* vector-scalar operations), we currently disable swap optimization. These operations are lane-sensitive by definition. A MentionsPartialVR flag is added for use in each swap table entry that mentions a scalar floating-point register without having special handling defined. A common idiom for PPC64LE is to convert a double-precision scalar to a vector by performing a splat operation. This ensures that the value can be referenced as V[0], as it would be for big endian, whereas just converting the scalar to a vector with a SUBREG_TO_REG operation leaves this value only in V[1]. A doubleword splat operation is one form of an XXPERMDI instruction, which takes one doubleword from a first operand and another doubleword from a second operand, with a two-bit selector operand indicating which doublewords are chosen. In the general case, an XXPERMDI can be permitted in a lane-swapped region provided that it is properly transformed to select the corresponding swapped values. This transformation is to reverse the order of the two input operands, and to reverse and complement the bits of the selector operand (derivation left as an exercise to the reader ;). A new test case that exercises the scalar-to-vector and generalized XXPERMDI transformations is added as CodeGen/PowerPC/swaps-le-5.ll. The patch also requires a change to CodeGen/PowerPC/swaps-le-3.ll to use CHECK-DAG instead of CHECK for two independent instructions that now appear in reverse order. There are two small unrelated changes that are added with this patch. First, the XXSLDWI instruction was incorrectly omitted from the list of lane-sensitive instructions; this is now fixed. Second, I observed that the same webs were being rejected over and over again for different reasons. Since it's sufficient to reject a web only once, I added a check for this to speed up the compilation time slightly. llvm-svn: 242081
2015-07-14 06:58:19 +08:00
else {
// We can still handle these if the two registers are not
// identical, by adjusting the form of the XXPERMDI.
SwapVector[VecIdx].IsSwappable = 1;
SwapVector[VecIdx].SpecialHandling = SHValues::SH_XXPERMDI;
}
[PPC64LE] Teach swap optimization about the doubleword splat idiom With a previous patch, the VSX swap optimization is able to recognize the doubleword load-splat idiom that can be implemented using lxvdsx. However, that does not cover a doubleword splat where the source is a register. We can implement this using xxspltd (a special form of xxpermdi). This patch teaches the swap optimization pass about this idiom. As a prerequisite, it also permits swap optimization to succeed for all forms of SUBREG_TO_REG. Previously we were conservative and only allowed SUBREG_TO_REG when it copied a full register. However, on reflection any form of SUBREG_TO_REG is safe in and of itself, so long as an unsafe operation is not performed on its result. In particular, a widening SUBREG_TO_REG often occurs as an input to a doubleword splat idiom, particularly in auto-vectorized code. The doubleword splat idiom is an XXPERMDI operation where both source registers are identical, and the selection mask is either 0 (splat the first element) or 3 (splat the second element). To determine whether the registers are identical, we use the existing mechanism for looking through "copy-like" operations. That mechanism has a side effect of marking the XXPERMDI operation as using a physical register, which would invalidate its presence in a swap-optimized region. This is correct for the form of XXPERMDI that performs a swap and hence would be removed, but is not what we want for a doubleword-splat variety of XXPERMDI. Therefore we reset the physical-register flag on the XXPERMDI when it represents a splat. A simple test case is added to verify that we generate the splat and that we also remove the xxswapd instructions that would otherwise be associated with the load and store of another operand. llvm-svn: 241285
2015-07-03 01:03:06 +08:00
// This is a doubleword splat if it is of the form
// XXPERMDI t, s, s, 0 or XXPERMDI t, s, s, 3. As above we
// must look through chains of copy-likes to find the source
// register. We turn off the marking for mention of a physical
// register, because splatting it is safe; the optimization
[PPC64LE] More improvements to VSX swap optimization This patch allows VSX swap optimization to succeed more frequently. Specifically, it is concerned with common code sequences that occur when copying a scalar floating-point value to a vector register. This patch currently handles cases where the floating-point value is already in a register, but does not yet handle loads (such as via an LXSDX scalar floating-point VSX load). That will be dealt with later. A typical case is when a scalar value comes in as a floating-point parameter. The value is copied into a virtual VSFRC register, and then a sequence of SUBREG_TO_REG and/or COPY operations will convert it to a full vector register of the class required by the context. If this vector register is then used as part of a lane-permuted computation, the original scalar value will be in the wrong lane. We can fix this by adding a swap operation following any widening SUBREG_TO_REG operation. Additional COPY operations may be needed around the swap operation in order to keep register assignment happy, but these are pro forma operations that will be removed by coalescing. If a scalar value is otherwise directly referenced in a computation (such as by one of the many XS* vector-scalar operations), we currently disable swap optimization. These operations are lane-sensitive by definition. A MentionsPartialVR flag is added for use in each swap table entry that mentions a scalar floating-point register without having special handling defined. A common idiom for PPC64LE is to convert a double-precision scalar to a vector by performing a splat operation. This ensures that the value can be referenced as V[0], as it would be for big endian, whereas just converting the scalar to a vector with a SUBREG_TO_REG operation leaves this value only in V[1]. A doubleword splat operation is one form of an XXPERMDI instruction, which takes one doubleword from a first operand and another doubleword from a second operand, with a two-bit selector operand indicating which doublewords are chosen. In the general case, an XXPERMDI can be permitted in a lane-swapped region provided that it is properly transformed to select the corresponding swapped values. This transformation is to reverse the order of the two input operands, and to reverse and complement the bits of the selector operand (derivation left as an exercise to the reader ;). A new test case that exercises the scalar-to-vector and generalized XXPERMDI transformations is added as CodeGen/PowerPC/swaps-le-5.ll. The patch also requires a change to CodeGen/PowerPC/swaps-le-3.ll to use CHECK-DAG instead of CHECK for two independent instructions that now appear in reverse order. There are two small unrelated changes that are added with this patch. First, the XXSLDWI instruction was incorrectly omitted from the list of lane-sensitive instructions; this is now fixed. Second, I observed that the same webs were being rejected over and over again for different reasons. Since it's sufficient to reject a web only once, I added a check for this to speed up the compilation time slightly. llvm-svn: 242081
2015-07-14 06:58:19 +08:00
// will not swap the value in the physical register. Whether
// or not the two input registers are identical, we can handle
// these by adjusting the form of the XXPERMDI.
} else if (immed == 0 || immed == 3) {
SwapVector[VecIdx].IsSwappable = 1;
SwapVector[VecIdx].SpecialHandling = SHValues::SH_XXPERMDI;
[PPC64LE] Teach swap optimization about the doubleword splat idiom With a previous patch, the VSX swap optimization is able to recognize the doubleword load-splat idiom that can be implemented using lxvdsx. However, that does not cover a doubleword splat where the source is a register. We can implement this using xxspltd (a special form of xxpermdi). This patch teaches the swap optimization pass about this idiom. As a prerequisite, it also permits swap optimization to succeed for all forms of SUBREG_TO_REG. Previously we were conservative and only allowed SUBREG_TO_REG when it copied a full register. However, on reflection any form of SUBREG_TO_REG is safe in and of itself, so long as an unsafe operation is not performed on its result. In particular, a widening SUBREG_TO_REG often occurs as an input to a doubleword splat idiom, particularly in auto-vectorized code. The doubleword splat idiom is an XXPERMDI operation where both source registers are identical, and the selection mask is either 0 (splat the first element) or 3 (splat the second element). To determine whether the registers are identical, we use the existing mechanism for looking through "copy-like" operations. That mechanism has a side effect of marking the XXPERMDI operation as using a physical register, which would invalidate its presence in a swap-optimized region. This is correct for the form of XXPERMDI that performs a swap and hence would be removed, but is not what we want for a doubleword-splat variety of XXPERMDI. Therefore we reset the physical-register flag on the XXPERMDI when it represents a splat. A simple test case is added to verify that we generate the splat and that we also remove the xxswapd instructions that would otherwise be associated with the load and store of another operand. llvm-svn: 241285
2015-07-03 01:03:06 +08:00
unsigned trueReg1 = lookThruCopyLike(MI.getOperand(1).getReg(),
VecIdx);
unsigned trueReg2 = lookThruCopyLike(MI.getOperand(2).getReg(),
VecIdx);
[PPC64LE] More improvements to VSX swap optimization This patch allows VSX swap optimization to succeed more frequently. Specifically, it is concerned with common code sequences that occur when copying a scalar floating-point value to a vector register. This patch currently handles cases where the floating-point value is already in a register, but does not yet handle loads (such as via an LXSDX scalar floating-point VSX load). That will be dealt with later. A typical case is when a scalar value comes in as a floating-point parameter. The value is copied into a virtual VSFRC register, and then a sequence of SUBREG_TO_REG and/or COPY operations will convert it to a full vector register of the class required by the context. If this vector register is then used as part of a lane-permuted computation, the original scalar value will be in the wrong lane. We can fix this by adding a swap operation following any widening SUBREG_TO_REG operation. Additional COPY operations may be needed around the swap operation in order to keep register assignment happy, but these are pro forma operations that will be removed by coalescing. If a scalar value is otherwise directly referenced in a computation (such as by one of the many XS* vector-scalar operations), we currently disable swap optimization. These operations are lane-sensitive by definition. A MentionsPartialVR flag is added for use in each swap table entry that mentions a scalar floating-point register without having special handling defined. A common idiom for PPC64LE is to convert a double-precision scalar to a vector by performing a splat operation. This ensures that the value can be referenced as V[0], as it would be for big endian, whereas just converting the scalar to a vector with a SUBREG_TO_REG operation leaves this value only in V[1]. A doubleword splat operation is one form of an XXPERMDI instruction, which takes one doubleword from a first operand and another doubleword from a second operand, with a two-bit selector operand indicating which doublewords are chosen. In the general case, an XXPERMDI can be permitted in a lane-swapped region provided that it is properly transformed to select the corresponding swapped values. This transformation is to reverse the order of the two input operands, and to reverse and complement the bits of the selector operand (derivation left as an exercise to the reader ;). A new test case that exercises the scalar-to-vector and generalized XXPERMDI transformations is added as CodeGen/PowerPC/swaps-le-5.ll. The patch also requires a change to CodeGen/PowerPC/swaps-le-3.ll to use CHECK-DAG instead of CHECK for two independent instructions that now appear in reverse order. There are two small unrelated changes that are added with this patch. First, the XXSLDWI instruction was incorrectly omitted from the list of lane-sensitive instructions; this is now fixed. Second, I observed that the same webs were being rejected over and over again for different reasons. Since it's sufficient to reject a web only once, I added a check for this to speed up the compilation time slightly. llvm-svn: 242081
2015-07-14 06:58:19 +08:00
if (trueReg1 == trueReg2)
[PPC64LE] Teach swap optimization about the doubleword splat idiom With a previous patch, the VSX swap optimization is able to recognize the doubleword load-splat idiom that can be implemented using lxvdsx. However, that does not cover a doubleword splat where the source is a register. We can implement this using xxspltd (a special form of xxpermdi). This patch teaches the swap optimization pass about this idiom. As a prerequisite, it also permits swap optimization to succeed for all forms of SUBREG_TO_REG. Previously we were conservative and only allowed SUBREG_TO_REG when it copied a full register. However, on reflection any form of SUBREG_TO_REG is safe in and of itself, so long as an unsafe operation is not performed on its result. In particular, a widening SUBREG_TO_REG often occurs as an input to a doubleword splat idiom, particularly in auto-vectorized code. The doubleword splat idiom is an XXPERMDI operation where both source registers are identical, and the selection mask is either 0 (splat the first element) or 3 (splat the second element). To determine whether the registers are identical, we use the existing mechanism for looking through "copy-like" operations. That mechanism has a side effect of marking the XXPERMDI operation as using a physical register, which would invalidate its presence in a swap-optimized region. This is correct for the form of XXPERMDI that performs a swap and hence would be removed, but is not what we want for a doubleword-splat variety of XXPERMDI. Therefore we reset the physical-register flag on the XXPERMDI when it represents a splat. A simple test case is added to verify that we generate the splat and that we also remove the xxswapd instructions that would otherwise be associated with the load and store of another operand. llvm-svn: 241285
2015-07-03 01:03:06 +08:00
SwapVector[VecIdx].MentionsPhysVR = 0;
[PPC64LE] More improvements to VSX swap optimization This patch allows VSX swap optimization to succeed more frequently. Specifically, it is concerned with common code sequences that occur when copying a scalar floating-point value to a vector register. This patch currently handles cases where the floating-point value is already in a register, but does not yet handle loads (such as via an LXSDX scalar floating-point VSX load). That will be dealt with later. A typical case is when a scalar value comes in as a floating-point parameter. The value is copied into a virtual VSFRC register, and then a sequence of SUBREG_TO_REG and/or COPY operations will convert it to a full vector register of the class required by the context. If this vector register is then used as part of a lane-permuted computation, the original scalar value will be in the wrong lane. We can fix this by adding a swap operation following any widening SUBREG_TO_REG operation. Additional COPY operations may be needed around the swap operation in order to keep register assignment happy, but these are pro forma operations that will be removed by coalescing. If a scalar value is otherwise directly referenced in a computation (such as by one of the many XS* vector-scalar operations), we currently disable swap optimization. These operations are lane-sensitive by definition. A MentionsPartialVR flag is added for use in each swap table entry that mentions a scalar floating-point register without having special handling defined. A common idiom for PPC64LE is to convert a double-precision scalar to a vector by performing a splat operation. This ensures that the value can be referenced as V[0], as it would be for big endian, whereas just converting the scalar to a vector with a SUBREG_TO_REG operation leaves this value only in V[1]. A doubleword splat operation is one form of an XXPERMDI instruction, which takes one doubleword from a first operand and another doubleword from a second operand, with a two-bit selector operand indicating which doublewords are chosen. In the general case, an XXPERMDI can be permitted in a lane-swapped region provided that it is properly transformed to select the corresponding swapped values. This transformation is to reverse the order of the two input operands, and to reverse and complement the bits of the selector operand (derivation left as an exercise to the reader ;). A new test case that exercises the scalar-to-vector and generalized XXPERMDI transformations is added as CodeGen/PowerPC/swaps-le-5.ll. The patch also requires a change to CodeGen/PowerPC/swaps-le-3.ll to use CHECK-DAG instead of CHECK for two independent instructions that now appear in reverse order. There are two small unrelated changes that are added with this patch. First, the XXSLDWI instruction was incorrectly omitted from the list of lane-sensitive instructions; this is now fixed. Second, I observed that the same webs were being rejected over and over again for different reasons. Since it's sufficient to reject a web only once, I added a check for this to speed up the compilation time slightly. llvm-svn: 242081
2015-07-14 06:58:19 +08:00
} else {
// We can still handle these by adjusting the form of the XXPERMDI.
SwapVector[VecIdx].IsSwappable = 1;
SwapVector[VecIdx].SpecialHandling = SHValues::SH_XXPERMDI;
[PPC64LE] Teach swap optimization about the doubleword splat idiom With a previous patch, the VSX swap optimization is able to recognize the doubleword load-splat idiom that can be implemented using lxvdsx. However, that does not cover a doubleword splat where the source is a register. We can implement this using xxspltd (a special form of xxpermdi). This patch teaches the swap optimization pass about this idiom. As a prerequisite, it also permits swap optimization to succeed for all forms of SUBREG_TO_REG. Previously we were conservative and only allowed SUBREG_TO_REG when it copied a full register. However, on reflection any form of SUBREG_TO_REG is safe in and of itself, so long as an unsafe operation is not performed on its result. In particular, a widening SUBREG_TO_REG often occurs as an input to a doubleword splat idiom, particularly in auto-vectorized code. The doubleword splat idiom is an XXPERMDI operation where both source registers are identical, and the selection mask is either 0 (splat the first element) or 3 (splat the second element). To determine whether the registers are identical, we use the existing mechanism for looking through "copy-like" operations. That mechanism has a side effect of marking the XXPERMDI operation as using a physical register, which would invalidate its presence in a swap-optimized region. This is correct for the form of XXPERMDI that performs a swap and hence would be removed, but is not what we want for a doubleword-splat variety of XXPERMDI. Therefore we reset the physical-register flag on the XXPERMDI when it represents a splat. A simple test case is added to verify that we generate the splat and that we also remove the xxswapd instructions that would otherwise be associated with the load and store of another operand. llvm-svn: 241285
2015-07-03 01:03:06 +08:00
}
[PPC64LE] Remove unnecessary swaps from lane-insensitive vector computations This patch adds a new SSA MI pass that runs on little-endian PPC64 code with VSX enabled. Loads and stores of 4x32 and 2x64 vectors without alignment constraints are accomplished for little-endian using lxvd2x/xxswapd and xxswapd/stxvd2x. The existence of the additional xxswapd instructions hurts performance in comparison with big-endian code, but they are necessary in the general case to support correct semantics. However, the general case does not apply to most vector code. Many vector instructions are lane-insensitive; they do not "care" which lanes the parallel computations are performed within, provided that the resulting data is stored into the correct locations. Thus this pass looks for computations that perform only lane-insensitive operations, and remove the unnecessary swaps from loads and stores in such computations. Future improvements will allow computations using certain lane-sensitive operations to also be optimized in this manner, by modifying the lane-sensitive operations to account for the permuted order of the lanes. However, this patch only adds the infrastructure to permit this; no lane-sensitive operations are optimized at this time. This code is heavily exercised by the various vectorizing applications in the projects/test-suite tree. For the time being, I have only added one simple test case to demonstrate what the pass is doing. Although it is quite simple, it provides coverage for much of the code, including the special case handling of copies and subreg-to-reg operations feeding the swaps. I plan to add additional tests in the future as I fill in more of the "special handling" code. Two existing tests were affected, because they expected the swaps to be present, but they are now removed. llvm-svn: 235910
2015-04-28 03:57:34 +08:00
break;
[PPC64LE] Teach swap optimization about the doubleword splat idiom With a previous patch, the VSX swap optimization is able to recognize the doubleword load-splat idiom that can be implemented using lxvdsx. However, that does not cover a doubleword splat where the source is a register. We can implement this using xxspltd (a special form of xxpermdi). This patch teaches the swap optimization pass about this idiom. As a prerequisite, it also permits swap optimization to succeed for all forms of SUBREG_TO_REG. Previously we were conservative and only allowed SUBREG_TO_REG when it copied a full register. However, on reflection any form of SUBREG_TO_REG is safe in and of itself, so long as an unsafe operation is not performed on its result. In particular, a widening SUBREG_TO_REG often occurs as an input to a doubleword splat idiom, particularly in auto-vectorized code. The doubleword splat idiom is an XXPERMDI operation where both source registers are identical, and the selection mask is either 0 (splat the first element) or 3 (splat the second element). To determine whether the registers are identical, we use the existing mechanism for looking through "copy-like" operations. That mechanism has a side effect of marking the XXPERMDI operation as using a physical register, which would invalidate its presence in a swap-optimized region. This is correct for the form of XXPERMDI that performs a swap and hence would be removed, but is not what we want for a doubleword-splat variety of XXPERMDI. Therefore we reset the physical-register flag on the XXPERMDI when it represents a splat. A simple test case is added to verify that we generate the splat and that we also remove the xxswapd instructions that would otherwise be associated with the load and store of another operand. llvm-svn: 241285
2015-07-03 01:03:06 +08:00
}
[PPC64LE] Remove unnecessary swaps from lane-insensitive vector computations This patch adds a new SSA MI pass that runs on little-endian PPC64 code with VSX enabled. Loads and stores of 4x32 and 2x64 vectors without alignment constraints are accomplished for little-endian using lxvd2x/xxswapd and xxswapd/stxvd2x. The existence of the additional xxswapd instructions hurts performance in comparison with big-endian code, but they are necessary in the general case to support correct semantics. However, the general case does not apply to most vector code. Many vector instructions are lane-insensitive; they do not "care" which lanes the parallel computations are performed within, provided that the resulting data is stored into the correct locations. Thus this pass looks for computations that perform only lane-insensitive operations, and remove the unnecessary swaps from loads and stores in such computations. Future improvements will allow computations using certain lane-sensitive operations to also be optimized in this manner, by modifying the lane-sensitive operations to account for the permuted order of the lanes. However, this patch only adds the infrastructure to permit this; no lane-sensitive operations are optimized at this time. This code is heavily exercised by the various vectorizing applications in the projects/test-suite tree. For the time being, I have only added one simple test case to demonstrate what the pass is doing. Although it is quite simple, it provides coverage for much of the code, including the special case handling of copies and subreg-to-reg operations feeding the swaps. I plan to add additional tests in the future as I fill in more of the "special handling" code. Two existing tests were affected, because they expected the swaps to be present, but they are now removed. llvm-svn: 235910
2015-04-28 03:57:34 +08:00
case PPC::LVX:
// Non-permuting loads are currently unsafe. We can use special
// handling for this in the future. By not marking these as
// IsSwap, we ensure computations containing them will be rejected
// for now.
SwapVector[VecIdx].IsLoad = 1;
break;
case PPC::LXVD2X:
case PPC::LXVW4X:
// Permuting loads are marked as both load and swap, and are
// safe for optimization.
SwapVector[VecIdx].IsLoad = 1;
SwapVector[VecIdx].IsSwap = 1;
break;
[PPC64LE] More vector swap optimization TLC This makes one substantive change and a few stylistic changes to the VSX swap optimization pass. The substantive change is to permit LXSDX and LXSSPX instructions to participate in swap optimization computations. The previous change to insert a swap following a SUBREG_TO_REG widening operation makes this almost trivial. I experimented with also permitting STXSDX and STXSSPX instructions. This can be done using similar techniques: we could insert a swap prior to a narrowing COPY operation, and then permit these stores to participate. I prototyped this, but discovered that the pattern of a narrowing COPY followed by an STXSDX does not occur in any of our test-suite code. So instead, I added commentary indicating that this could be done. Other TLC: - I changed SH_COPYSCALAR to SH_COPYWIDEN to more clearly indicate the direction of the copy. - I factored the insertion of swap instructions into a separate function. Finally, I added a new test case to check that the scalar-to-vector loads are working properly with swap optimization. llvm-svn: 242838
2015-07-22 05:40:17 +08:00
case PPC::LXSDX:
case PPC::LXSSPX:
// A load of a floating-point value into the high-order half of
// a vector register is safe, provided that we introduce a swap
// following the load, which will be done by the SUBREG_TO_REG
// support. So just mark these as safe.
SwapVector[VecIdx].IsLoad = 1;
SwapVector[VecIdx].IsSwappable = 1;
break;
[PPC64LE] Remove unnecessary swaps from lane-insensitive vector computations This patch adds a new SSA MI pass that runs on little-endian PPC64 code with VSX enabled. Loads and stores of 4x32 and 2x64 vectors without alignment constraints are accomplished for little-endian using lxvd2x/xxswapd and xxswapd/stxvd2x. The existence of the additional xxswapd instructions hurts performance in comparison with big-endian code, but they are necessary in the general case to support correct semantics. However, the general case does not apply to most vector code. Many vector instructions are lane-insensitive; they do not "care" which lanes the parallel computations are performed within, provided that the resulting data is stored into the correct locations. Thus this pass looks for computations that perform only lane-insensitive operations, and remove the unnecessary swaps from loads and stores in such computations. Future improvements will allow computations using certain lane-sensitive operations to also be optimized in this manner, by modifying the lane-sensitive operations to account for the permuted order of the lanes. However, this patch only adds the infrastructure to permit this; no lane-sensitive operations are optimized at this time. This code is heavily exercised by the various vectorizing applications in the projects/test-suite tree. For the time being, I have only added one simple test case to demonstrate what the pass is doing. Although it is quite simple, it provides coverage for much of the code, including the special case handling of copies and subreg-to-reg operations feeding the swaps. I plan to add additional tests in the future as I fill in more of the "special handling" code. Two existing tests were affected, because they expected the swaps to be present, but they are now removed. llvm-svn: 235910
2015-04-28 03:57:34 +08:00
case PPC::STVX:
// Non-permuting stores are currently unsafe. We can use special
// handling for this in the future. By not marking these as
// IsSwap, we ensure computations containing them will be rejected
// for now.
SwapVector[VecIdx].IsStore = 1;
break;
case PPC::STXVD2X:
case PPC::STXVW4X:
// Permuting stores are marked as both store and swap, and are
// safe for optimization.
SwapVector[VecIdx].IsStore = 1;
SwapVector[VecIdx].IsSwap = 1;
break;
case PPC::COPY:
// These are fine provided they are moving between full vector
// register classes.
if (isVecReg(MI.getOperand(0).getReg()) &&
isVecReg(MI.getOperand(1).getReg()))
SwapVector[VecIdx].IsSwappable = 1;
[PPC64LE] More improvements to VSX swap optimization This patch allows VSX swap optimization to succeed more frequently. Specifically, it is concerned with common code sequences that occur when copying a scalar floating-point value to a vector register. This patch currently handles cases where the floating-point value is already in a register, but does not yet handle loads (such as via an LXSDX scalar floating-point VSX load). That will be dealt with later. A typical case is when a scalar value comes in as a floating-point parameter. The value is copied into a virtual VSFRC register, and then a sequence of SUBREG_TO_REG and/or COPY operations will convert it to a full vector register of the class required by the context. If this vector register is then used as part of a lane-permuted computation, the original scalar value will be in the wrong lane. We can fix this by adding a swap operation following any widening SUBREG_TO_REG operation. Additional COPY operations may be needed around the swap operation in order to keep register assignment happy, but these are pro forma operations that will be removed by coalescing. If a scalar value is otherwise directly referenced in a computation (such as by one of the many XS* vector-scalar operations), we currently disable swap optimization. These operations are lane-sensitive by definition. A MentionsPartialVR flag is added for use in each swap table entry that mentions a scalar floating-point register without having special handling defined. A common idiom for PPC64LE is to convert a double-precision scalar to a vector by performing a splat operation. This ensures that the value can be referenced as V[0], as it would be for big endian, whereas just converting the scalar to a vector with a SUBREG_TO_REG operation leaves this value only in V[1]. A doubleword splat operation is one form of an XXPERMDI instruction, which takes one doubleword from a first operand and another doubleword from a second operand, with a two-bit selector operand indicating which doublewords are chosen. In the general case, an XXPERMDI can be permitted in a lane-swapped region provided that it is properly transformed to select the corresponding swapped values. This transformation is to reverse the order of the two input operands, and to reverse and complement the bits of the selector operand (derivation left as an exercise to the reader ;). A new test case that exercises the scalar-to-vector and generalized XXPERMDI transformations is added as CodeGen/PowerPC/swaps-le-5.ll. The patch also requires a change to CodeGen/PowerPC/swaps-le-3.ll to use CHECK-DAG instead of CHECK for two independent instructions that now appear in reverse order. There are two small unrelated changes that are added with this patch. First, the XXSLDWI instruction was incorrectly omitted from the list of lane-sensitive instructions; this is now fixed. Second, I observed that the same webs were being rejected over and over again for different reasons. Since it's sufficient to reject a web only once, I added a check for this to speed up the compilation time slightly. llvm-svn: 242081
2015-07-14 06:58:19 +08:00
// If we have a copy from one scalar floating-point register
// to another, we can accept this even if it is a physical
// register. The only way this gets involved is if it feeds
// a SUBREG_TO_REG, which is handled by introducing a swap.
else if (isScalarVecReg(MI.getOperand(0).getReg()) &&
isScalarVecReg(MI.getOperand(1).getReg()))
SwapVector[VecIdx].IsSwappable = 1;
break;
case PPC::SUBREG_TO_REG: {
// These are fine provided they are moving between full vector
// register classes. If they are moving from a scalar
// floating-point class to a vector class, we can handle those
// as well, provided we introduce a swap. It is generally the
// case that we will introduce fewer swaps than we remove, but
// (FIXME) a cost model could be used. However, introduced
// swaps could potentially be CSEd, so this is not trivial.
if (isVecReg(MI.getOperand(0).getReg()) &&
isVecReg(MI.getOperand(2).getReg()))
SwapVector[VecIdx].IsSwappable = 1;
else if (isVecReg(MI.getOperand(0).getReg()) &&
isScalarVecReg(MI.getOperand(2).getReg())) {
SwapVector[VecIdx].IsSwappable = 1;
[PPC64LE] More vector swap optimization TLC This makes one substantive change and a few stylistic changes to the VSX swap optimization pass. The substantive change is to permit LXSDX and LXSSPX instructions to participate in swap optimization computations. The previous change to insert a swap following a SUBREG_TO_REG widening operation makes this almost trivial. I experimented with also permitting STXSDX and STXSSPX instructions. This can be done using similar techniques: we could insert a swap prior to a narrowing COPY operation, and then permit these stores to participate. I prototyped this, but discovered that the pattern of a narrowing COPY followed by an STXSDX does not occur in any of our test-suite code. So instead, I added commentary indicating that this could be done. Other TLC: - I changed SH_COPYSCALAR to SH_COPYWIDEN to more clearly indicate the direction of the copy. - I factored the insertion of swap instructions into a separate function. Finally, I added a new test case to check that the scalar-to-vector loads are working properly with swap optimization. llvm-svn: 242838
2015-07-22 05:40:17 +08:00
SwapVector[VecIdx].SpecialHandling = SHValues::SH_COPYWIDEN;
[PPC64LE] More improvements to VSX swap optimization This patch allows VSX swap optimization to succeed more frequently. Specifically, it is concerned with common code sequences that occur when copying a scalar floating-point value to a vector register. This patch currently handles cases where the floating-point value is already in a register, but does not yet handle loads (such as via an LXSDX scalar floating-point VSX load). That will be dealt with later. A typical case is when a scalar value comes in as a floating-point parameter. The value is copied into a virtual VSFRC register, and then a sequence of SUBREG_TO_REG and/or COPY operations will convert it to a full vector register of the class required by the context. If this vector register is then used as part of a lane-permuted computation, the original scalar value will be in the wrong lane. We can fix this by adding a swap operation following any widening SUBREG_TO_REG operation. Additional COPY operations may be needed around the swap operation in order to keep register assignment happy, but these are pro forma operations that will be removed by coalescing. If a scalar value is otherwise directly referenced in a computation (such as by one of the many XS* vector-scalar operations), we currently disable swap optimization. These operations are lane-sensitive by definition. A MentionsPartialVR flag is added for use in each swap table entry that mentions a scalar floating-point register without having special handling defined. A common idiom for PPC64LE is to convert a double-precision scalar to a vector by performing a splat operation. This ensures that the value can be referenced as V[0], as it would be for big endian, whereas just converting the scalar to a vector with a SUBREG_TO_REG operation leaves this value only in V[1]. A doubleword splat operation is one form of an XXPERMDI instruction, which takes one doubleword from a first operand and another doubleword from a second operand, with a two-bit selector operand indicating which doublewords are chosen. In the general case, an XXPERMDI can be permitted in a lane-swapped region provided that it is properly transformed to select the corresponding swapped values. This transformation is to reverse the order of the two input operands, and to reverse and complement the bits of the selector operand (derivation left as an exercise to the reader ;). A new test case that exercises the scalar-to-vector and generalized XXPERMDI transformations is added as CodeGen/PowerPC/swaps-le-5.ll. The patch also requires a change to CodeGen/PowerPC/swaps-le-3.ll to use CHECK-DAG instead of CHECK for two independent instructions that now appear in reverse order. There are two small unrelated changes that are added with this patch. First, the XXSLDWI instruction was incorrectly omitted from the list of lane-sensitive instructions; this is now fixed. Second, I observed that the same webs were being rejected over and over again for different reasons. Since it's sufficient to reject a web only once, I added a check for this to speed up the compilation time slightly. llvm-svn: 242081
2015-07-14 06:58:19 +08:00
}
[PPC64LE] Remove unnecessary swaps from lane-insensitive vector computations This patch adds a new SSA MI pass that runs on little-endian PPC64 code with VSX enabled. Loads and stores of 4x32 and 2x64 vectors without alignment constraints are accomplished for little-endian using lxvd2x/xxswapd and xxswapd/stxvd2x. The existence of the additional xxswapd instructions hurts performance in comparison with big-endian code, but they are necessary in the general case to support correct semantics. However, the general case does not apply to most vector code. Many vector instructions are lane-insensitive; they do not "care" which lanes the parallel computations are performed within, provided that the resulting data is stored into the correct locations. Thus this pass looks for computations that perform only lane-insensitive operations, and remove the unnecessary swaps from loads and stores in such computations. Future improvements will allow computations using certain lane-sensitive operations to also be optimized in this manner, by modifying the lane-sensitive operations to account for the permuted order of the lanes. However, this patch only adds the infrastructure to permit this; no lane-sensitive operations are optimized at this time. This code is heavily exercised by the various vectorizing applications in the projects/test-suite tree. For the time being, I have only added one simple test case to demonstrate what the pass is doing. Although it is quite simple, it provides coverage for much of the code, including the special case handling of copies and subreg-to-reg operations feeding the swaps. I plan to add additional tests in the future as I fill in more of the "special handling" code. Two existing tests were affected, because they expected the swaps to be present, but they are now removed. llvm-svn: 235910
2015-04-28 03:57:34 +08:00
break;
[PPC64LE] More improvements to VSX swap optimization This patch allows VSX swap optimization to succeed more frequently. Specifically, it is concerned with common code sequences that occur when copying a scalar floating-point value to a vector register. This patch currently handles cases where the floating-point value is already in a register, but does not yet handle loads (such as via an LXSDX scalar floating-point VSX load). That will be dealt with later. A typical case is when a scalar value comes in as a floating-point parameter. The value is copied into a virtual VSFRC register, and then a sequence of SUBREG_TO_REG and/or COPY operations will convert it to a full vector register of the class required by the context. If this vector register is then used as part of a lane-permuted computation, the original scalar value will be in the wrong lane. We can fix this by adding a swap operation following any widening SUBREG_TO_REG operation. Additional COPY operations may be needed around the swap operation in order to keep register assignment happy, but these are pro forma operations that will be removed by coalescing. If a scalar value is otherwise directly referenced in a computation (such as by one of the many XS* vector-scalar operations), we currently disable swap optimization. These operations are lane-sensitive by definition. A MentionsPartialVR flag is added for use in each swap table entry that mentions a scalar floating-point register without having special handling defined. A common idiom for PPC64LE is to convert a double-precision scalar to a vector by performing a splat operation. This ensures that the value can be referenced as V[0], as it would be for big endian, whereas just converting the scalar to a vector with a SUBREG_TO_REG operation leaves this value only in V[1]. A doubleword splat operation is one form of an XXPERMDI instruction, which takes one doubleword from a first operand and another doubleword from a second operand, with a two-bit selector operand indicating which doublewords are chosen. In the general case, an XXPERMDI can be permitted in a lane-swapped region provided that it is properly transformed to select the corresponding swapped values. This transformation is to reverse the order of the two input operands, and to reverse and complement the bits of the selector operand (derivation left as an exercise to the reader ;). A new test case that exercises the scalar-to-vector and generalized XXPERMDI transformations is added as CodeGen/PowerPC/swaps-le-5.ll. The patch also requires a change to CodeGen/PowerPC/swaps-le-3.ll to use CHECK-DAG instead of CHECK for two independent instructions that now appear in reverse order. There are two small unrelated changes that are added with this patch. First, the XXSLDWI instruction was incorrectly omitted from the list of lane-sensitive instructions; this is now fixed. Second, I observed that the same webs were being rejected over and over again for different reasons. Since it's sufficient to reject a web only once, I added a check for this to speed up the compilation time slightly. llvm-svn: 242081
2015-07-14 06:58:19 +08:00
}
[PPC64LE] Remove unnecessary swaps from lane-insensitive vector computations This patch adds a new SSA MI pass that runs on little-endian PPC64 code with VSX enabled. Loads and stores of 4x32 and 2x64 vectors without alignment constraints are accomplished for little-endian using lxvd2x/xxswapd and xxswapd/stxvd2x. The existence of the additional xxswapd instructions hurts performance in comparison with big-endian code, but they are necessary in the general case to support correct semantics. However, the general case does not apply to most vector code. Many vector instructions are lane-insensitive; they do not "care" which lanes the parallel computations are performed within, provided that the resulting data is stored into the correct locations. Thus this pass looks for computations that perform only lane-insensitive operations, and remove the unnecessary swaps from loads and stores in such computations. Future improvements will allow computations using certain lane-sensitive operations to also be optimized in this manner, by modifying the lane-sensitive operations to account for the permuted order of the lanes. However, this patch only adds the infrastructure to permit this; no lane-sensitive operations are optimized at this time. This code is heavily exercised by the various vectorizing applications in the projects/test-suite tree. For the time being, I have only added one simple test case to demonstrate what the pass is doing. Although it is quite simple, it provides coverage for much of the code, including the special case handling of copies and subreg-to-reg operations feeding the swaps. I plan to add additional tests in the future as I fill in more of the "special handling" code. Two existing tests were affected, because they expected the swaps to be present, but they are now removed. llvm-svn: 235910
2015-04-28 03:57:34 +08:00
case PPC::VSPLTB:
case PPC::VSPLTH:
case PPC::VSPLTW:
// Splats are lane-sensitive, but we can use special handling
// to adjust the source lane for the splat. This is not yet
// implemented. When it is, we need to uncomment the following:
[PPC64LE] Adjust vector splats during VSX swap optimization The initial code drop for VSX swap optimization permitted the optimization only when all operations in a web of related computation are lane-insensitive. For some lane-sensitive operations, we can still permit the optimization provided that we make adjustments to those operations. This patch adds special handling for vector splats so that their presence doesn't kill the optimization. Vector splats are lane-sensitive since they identify by number a vector element to be used as the source of a splat. When swap optimizations take place, the desired vector element will move to the opposite doubleword of the quadword vector. We thus replace the index I by (I + N/2) % N, where N is the number of elements in the vector. A new test case is added to test that swap optimization succeeds when vector splats are present, and that the proper input element is used as the source of the splat. An ancillary change removes SH_BUILDVEC as one of the kinds of special handling that may be required by VSX swap optimization. From experience with GCC, I had expected to need some modifications for vector build operations, but I did not find that to be the case. llvm-svn: 236606
2015-05-06 23:40:46 +08:00
SwapVector[VecIdx].IsSwappable = 1;
[PPC64LE] Remove unnecessary swaps from lane-insensitive vector computations This patch adds a new SSA MI pass that runs on little-endian PPC64 code with VSX enabled. Loads and stores of 4x32 and 2x64 vectors without alignment constraints are accomplished for little-endian using lxvd2x/xxswapd and xxswapd/stxvd2x. The existence of the additional xxswapd instructions hurts performance in comparison with big-endian code, but they are necessary in the general case to support correct semantics. However, the general case does not apply to most vector code. Many vector instructions are lane-insensitive; they do not "care" which lanes the parallel computations are performed within, provided that the resulting data is stored into the correct locations. Thus this pass looks for computations that perform only lane-insensitive operations, and remove the unnecessary swaps from loads and stores in such computations. Future improvements will allow computations using certain lane-sensitive operations to also be optimized in this manner, by modifying the lane-sensitive operations to account for the permuted order of the lanes. However, this patch only adds the infrastructure to permit this; no lane-sensitive operations are optimized at this time. This code is heavily exercised by the various vectorizing applications in the projects/test-suite tree. For the time being, I have only added one simple test case to demonstrate what the pass is doing. Although it is quite simple, it provides coverage for much of the code, including the special case handling of copies and subreg-to-reg operations feeding the swaps. I plan to add additional tests in the future as I fill in more of the "special handling" code. Two existing tests were affected, because they expected the swaps to be present, but they are now removed. llvm-svn: 235910
2015-04-28 03:57:34 +08:00
SwapVector[VecIdx].SpecialHandling = SHValues::SH_SPLAT;
break;
// The presence of the following lane-sensitive operations in a
// web will kill the optimization, at least for now. For these
// we do nothing, causing the optimization to fail.
// FIXME: Some of these could be permitted with special handling,
// and will be phased in as time permits.
// FIXME: There is no simple and maintainable way to express a set
// of opcodes having a common attribute in TableGen. Should this
// change, this is a prime candidate to use such a mechanism.
case PPC::INLINEASM:
case PPC::EXTRACT_SUBREG:
case PPC::INSERT_SUBREG:
case PPC::COPY_TO_REGCLASS:
case PPC::LVEBX:
case PPC::LVEHX:
case PPC::LVEWX:
case PPC::LVSL:
case PPC::LVSR:
case PPC::LVXL:
case PPC::STVEBX:
case PPC::STVEHX:
case PPC::STVEWX:
case PPC::STVXL:
[PPC64LE] More vector swap optimization TLC This makes one substantive change and a few stylistic changes to the VSX swap optimization pass. The substantive change is to permit LXSDX and LXSSPX instructions to participate in swap optimization computations. The previous change to insert a swap following a SUBREG_TO_REG widening operation makes this almost trivial. I experimented with also permitting STXSDX and STXSSPX instructions. This can be done using similar techniques: we could insert a swap prior to a narrowing COPY operation, and then permit these stores to participate. I prototyped this, but discovered that the pattern of a narrowing COPY followed by an STXSDX does not occur in any of our test-suite code. So instead, I added commentary indicating that this could be done. Other TLC: - I changed SH_COPYSCALAR to SH_COPYWIDEN to more clearly indicate the direction of the copy. - I factored the insertion of swap instructions into a separate function. Finally, I added a new test case to check that the scalar-to-vector loads are working properly with swap optimization. llvm-svn: 242838
2015-07-22 05:40:17 +08:00
// We can handle STXSDX and STXSSPX similarly to LXSDX and LXSSPX,
// by adding special handling for narrowing copies as well as
// widening ones. However, I've experimented with this, and in
// practice we currently do not appear to use STXSDX fed by
// a narrowing copy from a full vector register. Since I can't
// generate any useful test cases, I've left this alone for now.
[PPC64LE] Remove unnecessary swaps from lane-insensitive vector computations This patch adds a new SSA MI pass that runs on little-endian PPC64 code with VSX enabled. Loads and stores of 4x32 and 2x64 vectors without alignment constraints are accomplished for little-endian using lxvd2x/xxswapd and xxswapd/stxvd2x. The existence of the additional xxswapd instructions hurts performance in comparison with big-endian code, but they are necessary in the general case to support correct semantics. However, the general case does not apply to most vector code. Many vector instructions are lane-insensitive; they do not "care" which lanes the parallel computations are performed within, provided that the resulting data is stored into the correct locations. Thus this pass looks for computations that perform only lane-insensitive operations, and remove the unnecessary swaps from loads and stores in such computations. Future improvements will allow computations using certain lane-sensitive operations to also be optimized in this manner, by modifying the lane-sensitive operations to account for the permuted order of the lanes. However, this patch only adds the infrastructure to permit this; no lane-sensitive operations are optimized at this time. This code is heavily exercised by the various vectorizing applications in the projects/test-suite tree. For the time being, I have only added one simple test case to demonstrate what the pass is doing. Although it is quite simple, it provides coverage for much of the code, including the special case handling of copies and subreg-to-reg operations feeding the swaps. I plan to add additional tests in the future as I fill in more of the "special handling" code. Two existing tests were affected, because they expected the swaps to be present, but they are now removed. llvm-svn: 235910
2015-04-28 03:57:34 +08:00
case PPC::STXSDX:
[PPC64LE] More vector swap optimization TLC This makes one substantive change and a few stylistic changes to the VSX swap optimization pass. The substantive change is to permit LXSDX and LXSSPX instructions to participate in swap optimization computations. The previous change to insert a swap following a SUBREG_TO_REG widening operation makes this almost trivial. I experimented with also permitting STXSDX and STXSSPX instructions. This can be done using similar techniques: we could insert a swap prior to a narrowing COPY operation, and then permit these stores to participate. I prototyped this, but discovered that the pattern of a narrowing COPY followed by an STXSDX does not occur in any of our test-suite code. So instead, I added commentary indicating that this could be done. Other TLC: - I changed SH_COPYSCALAR to SH_COPYWIDEN to more clearly indicate the direction of the copy. - I factored the insertion of swap instructions into a separate function. Finally, I added a new test case to check that the scalar-to-vector loads are working properly with swap optimization. llvm-svn: 242838
2015-07-22 05:40:17 +08:00
case PPC::STXSSPX:
[PPC64LE] Remove unnecessary swaps from lane-insensitive vector computations This patch adds a new SSA MI pass that runs on little-endian PPC64 code with VSX enabled. Loads and stores of 4x32 and 2x64 vectors without alignment constraints are accomplished for little-endian using lxvd2x/xxswapd and xxswapd/stxvd2x. The existence of the additional xxswapd instructions hurts performance in comparison with big-endian code, but they are necessary in the general case to support correct semantics. However, the general case does not apply to most vector code. Many vector instructions are lane-insensitive; they do not "care" which lanes the parallel computations are performed within, provided that the resulting data is stored into the correct locations. Thus this pass looks for computations that perform only lane-insensitive operations, and remove the unnecessary swaps from loads and stores in such computations. Future improvements will allow computations using certain lane-sensitive operations to also be optimized in this manner, by modifying the lane-sensitive operations to account for the permuted order of the lanes. However, this patch only adds the infrastructure to permit this; no lane-sensitive operations are optimized at this time. This code is heavily exercised by the various vectorizing applications in the projects/test-suite tree. For the time being, I have only added one simple test case to demonstrate what the pass is doing. Although it is quite simple, it provides coverage for much of the code, including the special case handling of copies and subreg-to-reg operations feeding the swaps. I plan to add additional tests in the future as I fill in more of the "special handling" code. Two existing tests were affected, because they expected the swaps to be present, but they are now removed. llvm-svn: 235910
2015-04-28 03:57:34 +08:00
case PPC::VCIPHER:
case PPC::VCIPHERLAST:
case PPC::VMRGHB:
case PPC::VMRGHH:
case PPC::VMRGHW:
case PPC::VMRGLB:
case PPC::VMRGLH:
case PPC::VMRGLW:
case PPC::VMULESB:
case PPC::VMULESH:
case PPC::VMULESW:
case PPC::VMULEUB:
case PPC::VMULEUH:
case PPC::VMULEUW:
case PPC::VMULOSB:
case PPC::VMULOSH:
case PPC::VMULOSW:
case PPC::VMULOUB:
case PPC::VMULOUH:
case PPC::VMULOUW:
case PPC::VNCIPHER:
case PPC::VNCIPHERLAST:
case PPC::VPERM:
case PPC::VPERMXOR:
case PPC::VPKPX:
case PPC::VPKSHSS:
case PPC::VPKSHUS:
[PPC64] Add vector pack/unpack support from ISA 2.07 This patch adds support for the following new instructions in the Power ISA 2.07: vpksdss vpksdus vpkudus vpkudum vupkhsw vupklsw These instructions are available through the vec_packs, vec_packsu, vec_unpackh, and vec_unpackl built-in interfaces. These are lane-sensitive instructions, so the built-ins have different implementations for big- and little-endian, and the instructions must be marked as killing the vector swap optimization for now. The first three instructions perform saturating pack operations. The fourth performs a modulo pack operation, which means it can be represented with a vector shuffle, and conversely the appropriate vector shuffles may cause this instruction to be generated. The other instructions are only generated via built-in support for now. Appropriate tests have been added. There is a companion patch to clang for the rest of this support. llvm-svn: 237499
2015-05-16 09:02:12 +08:00
case PPC::VPKSDSS:
case PPC::VPKSDUS:
[PPC64LE] Remove unnecessary swaps from lane-insensitive vector computations This patch adds a new SSA MI pass that runs on little-endian PPC64 code with VSX enabled. Loads and stores of 4x32 and 2x64 vectors without alignment constraints are accomplished for little-endian using lxvd2x/xxswapd and xxswapd/stxvd2x. The existence of the additional xxswapd instructions hurts performance in comparison with big-endian code, but they are necessary in the general case to support correct semantics. However, the general case does not apply to most vector code. Many vector instructions are lane-insensitive; they do not "care" which lanes the parallel computations are performed within, provided that the resulting data is stored into the correct locations. Thus this pass looks for computations that perform only lane-insensitive operations, and remove the unnecessary swaps from loads and stores in such computations. Future improvements will allow computations using certain lane-sensitive operations to also be optimized in this manner, by modifying the lane-sensitive operations to account for the permuted order of the lanes. However, this patch only adds the infrastructure to permit this; no lane-sensitive operations are optimized at this time. This code is heavily exercised by the various vectorizing applications in the projects/test-suite tree. For the time being, I have only added one simple test case to demonstrate what the pass is doing. Although it is quite simple, it provides coverage for much of the code, including the special case handling of copies and subreg-to-reg operations feeding the swaps. I plan to add additional tests in the future as I fill in more of the "special handling" code. Two existing tests were affected, because they expected the swaps to be present, but they are now removed. llvm-svn: 235910
2015-04-28 03:57:34 +08:00
case PPC::VPKSWSS:
case PPC::VPKSWUS:
[PPC64] Add vector pack/unpack support from ISA 2.07 This patch adds support for the following new instructions in the Power ISA 2.07: vpksdss vpksdus vpkudus vpkudum vupkhsw vupklsw These instructions are available through the vec_packs, vec_packsu, vec_unpackh, and vec_unpackl built-in interfaces. These are lane-sensitive instructions, so the built-ins have different implementations for big- and little-endian, and the instructions must be marked as killing the vector swap optimization for now. The first three instructions perform saturating pack operations. The fourth performs a modulo pack operation, which means it can be represented with a vector shuffle, and conversely the appropriate vector shuffles may cause this instruction to be generated. The other instructions are only generated via built-in support for now. Appropriate tests have been added. There is a companion patch to clang for the rest of this support. llvm-svn: 237499
2015-05-16 09:02:12 +08:00
case PPC::VPKUDUM:
case PPC::VPKUDUS:
[PPC64LE] Remove unnecessary swaps from lane-insensitive vector computations This patch adds a new SSA MI pass that runs on little-endian PPC64 code with VSX enabled. Loads and stores of 4x32 and 2x64 vectors without alignment constraints are accomplished for little-endian using lxvd2x/xxswapd and xxswapd/stxvd2x. The existence of the additional xxswapd instructions hurts performance in comparison with big-endian code, but they are necessary in the general case to support correct semantics. However, the general case does not apply to most vector code. Many vector instructions are lane-insensitive; they do not "care" which lanes the parallel computations are performed within, provided that the resulting data is stored into the correct locations. Thus this pass looks for computations that perform only lane-insensitive operations, and remove the unnecessary swaps from loads and stores in such computations. Future improvements will allow computations using certain lane-sensitive operations to also be optimized in this manner, by modifying the lane-sensitive operations to account for the permuted order of the lanes. However, this patch only adds the infrastructure to permit this; no lane-sensitive operations are optimized at this time. This code is heavily exercised by the various vectorizing applications in the projects/test-suite tree. For the time being, I have only added one simple test case to demonstrate what the pass is doing. Although it is quite simple, it provides coverage for much of the code, including the special case handling of copies and subreg-to-reg operations feeding the swaps. I plan to add additional tests in the future as I fill in more of the "special handling" code. Two existing tests were affected, because they expected the swaps to be present, but they are now removed. llvm-svn: 235910
2015-04-28 03:57:34 +08:00
case PPC::VPKUHUM:
case PPC::VPKUHUS:
case PPC::VPKUWUM:
case PPC::VPKUWUS:
case PPC::VPMSUMB:
case PPC::VPMSUMD:
case PPC::VPMSUMH:
case PPC::VPMSUMW:
case PPC::VRLB:
case PPC::VRLD:
case PPC::VRLH:
case PPC::VRLW:
case PPC::VSBOX:
case PPC::VSHASIGMAD:
case PPC::VSHASIGMAW:
case PPC::VSL:
case PPC::VSLDOI:
case PPC::VSLO:
case PPC::VSR:
case PPC::VSRO:
case PPC::VSUM2SWS:
case PPC::VSUM4SBS:
case PPC::VSUM4SHS:
case PPC::VSUM4UBS:
case PPC::VSUMSWS:
case PPC::VUPKHPX:
case PPC::VUPKHSB:
case PPC::VUPKHSH:
[PPC64] Add vector pack/unpack support from ISA 2.07 This patch adds support for the following new instructions in the Power ISA 2.07: vpksdss vpksdus vpkudus vpkudum vupkhsw vupklsw These instructions are available through the vec_packs, vec_packsu, vec_unpackh, and vec_unpackl built-in interfaces. These are lane-sensitive instructions, so the built-ins have different implementations for big- and little-endian, and the instructions must be marked as killing the vector swap optimization for now. The first three instructions perform saturating pack operations. The fourth performs a modulo pack operation, which means it can be represented with a vector shuffle, and conversely the appropriate vector shuffles may cause this instruction to be generated. The other instructions are only generated via built-in support for now. Appropriate tests have been added. There is a companion patch to clang for the rest of this support. llvm-svn: 237499
2015-05-16 09:02:12 +08:00
case PPC::VUPKHSW:
[PPC64LE] Remove unnecessary swaps from lane-insensitive vector computations This patch adds a new SSA MI pass that runs on little-endian PPC64 code with VSX enabled. Loads and stores of 4x32 and 2x64 vectors without alignment constraints are accomplished for little-endian using lxvd2x/xxswapd and xxswapd/stxvd2x. The existence of the additional xxswapd instructions hurts performance in comparison with big-endian code, but they are necessary in the general case to support correct semantics. However, the general case does not apply to most vector code. Many vector instructions are lane-insensitive; they do not "care" which lanes the parallel computations are performed within, provided that the resulting data is stored into the correct locations. Thus this pass looks for computations that perform only lane-insensitive operations, and remove the unnecessary swaps from loads and stores in such computations. Future improvements will allow computations using certain lane-sensitive operations to also be optimized in this manner, by modifying the lane-sensitive operations to account for the permuted order of the lanes. However, this patch only adds the infrastructure to permit this; no lane-sensitive operations are optimized at this time. This code is heavily exercised by the various vectorizing applications in the projects/test-suite tree. For the time being, I have only added one simple test case to demonstrate what the pass is doing. Although it is quite simple, it provides coverage for much of the code, including the special case handling of copies and subreg-to-reg operations feeding the swaps. I plan to add additional tests in the future as I fill in more of the "special handling" code. Two existing tests were affected, because they expected the swaps to be present, but they are now removed. llvm-svn: 235910
2015-04-28 03:57:34 +08:00
case PPC::VUPKLPX:
case PPC::VUPKLSB:
case PPC::VUPKLSH:
[PPC64] Add vector pack/unpack support from ISA 2.07 This patch adds support for the following new instructions in the Power ISA 2.07: vpksdss vpksdus vpkudus vpkudum vupkhsw vupklsw These instructions are available through the vec_packs, vec_packsu, vec_unpackh, and vec_unpackl built-in interfaces. These are lane-sensitive instructions, so the built-ins have different implementations for big- and little-endian, and the instructions must be marked as killing the vector swap optimization for now. The first three instructions perform saturating pack operations. The fourth performs a modulo pack operation, which means it can be represented with a vector shuffle, and conversely the appropriate vector shuffles may cause this instruction to be generated. The other instructions are only generated via built-in support for now. Appropriate tests have been added. There is a companion patch to clang for the rest of this support. llvm-svn: 237499
2015-05-16 09:02:12 +08:00
case PPC::VUPKLSW:
[PPC64LE] Remove unnecessary swaps from lane-insensitive vector computations This patch adds a new SSA MI pass that runs on little-endian PPC64 code with VSX enabled. Loads and stores of 4x32 and 2x64 vectors without alignment constraints are accomplished for little-endian using lxvd2x/xxswapd and xxswapd/stxvd2x. The existence of the additional xxswapd instructions hurts performance in comparison with big-endian code, but they are necessary in the general case to support correct semantics. However, the general case does not apply to most vector code. Many vector instructions are lane-insensitive; they do not "care" which lanes the parallel computations are performed within, provided that the resulting data is stored into the correct locations. Thus this pass looks for computations that perform only lane-insensitive operations, and remove the unnecessary swaps from loads and stores in such computations. Future improvements will allow computations using certain lane-sensitive operations to also be optimized in this manner, by modifying the lane-sensitive operations to account for the permuted order of the lanes. However, this patch only adds the infrastructure to permit this; no lane-sensitive operations are optimized at this time. This code is heavily exercised by the various vectorizing applications in the projects/test-suite tree. For the time being, I have only added one simple test case to demonstrate what the pass is doing. Although it is quite simple, it provides coverage for much of the code, including the special case handling of copies and subreg-to-reg operations feeding the swaps. I plan to add additional tests in the future as I fill in more of the "special handling" code. Two existing tests were affected, because they expected the swaps to be present, but they are now removed. llvm-svn: 235910
2015-04-28 03:57:34 +08:00
case PPC::XXMRGHW:
case PPC::XXMRGLW:
[PPC64LE] More improvements to VSX swap optimization This patch allows VSX swap optimization to succeed more frequently. Specifically, it is concerned with common code sequences that occur when copying a scalar floating-point value to a vector register. This patch currently handles cases where the floating-point value is already in a register, but does not yet handle loads (such as via an LXSDX scalar floating-point VSX load). That will be dealt with later. A typical case is when a scalar value comes in as a floating-point parameter. The value is copied into a virtual VSFRC register, and then a sequence of SUBREG_TO_REG and/or COPY operations will convert it to a full vector register of the class required by the context. If this vector register is then used as part of a lane-permuted computation, the original scalar value will be in the wrong lane. We can fix this by adding a swap operation following any widening SUBREG_TO_REG operation. Additional COPY operations may be needed around the swap operation in order to keep register assignment happy, but these are pro forma operations that will be removed by coalescing. If a scalar value is otherwise directly referenced in a computation (such as by one of the many XS* vector-scalar operations), we currently disable swap optimization. These operations are lane-sensitive by definition. A MentionsPartialVR flag is added for use in each swap table entry that mentions a scalar floating-point register without having special handling defined. A common idiom for PPC64LE is to convert a double-precision scalar to a vector by performing a splat operation. This ensures that the value can be referenced as V[0], as it would be for big endian, whereas just converting the scalar to a vector with a SUBREG_TO_REG operation leaves this value only in V[1]. A doubleword splat operation is one form of an XXPERMDI instruction, which takes one doubleword from a first operand and another doubleword from a second operand, with a two-bit selector operand indicating which doublewords are chosen. In the general case, an XXPERMDI can be permitted in a lane-swapped region provided that it is properly transformed to select the corresponding swapped values. This transformation is to reverse the order of the two input operands, and to reverse and complement the bits of the selector operand (derivation left as an exercise to the reader ;). A new test case that exercises the scalar-to-vector and generalized XXPERMDI transformations is added as CodeGen/PowerPC/swaps-le-5.ll. The patch also requires a change to CodeGen/PowerPC/swaps-le-3.ll to use CHECK-DAG instead of CHECK for two independent instructions that now appear in reverse order. There are two small unrelated changes that are added with this patch. First, the XXSLDWI instruction was incorrectly omitted from the list of lane-sensitive instructions; this is now fixed. Second, I observed that the same webs were being rejected over and over again for different reasons. Since it's sufficient to reject a web only once, I added a check for this to speed up the compilation time slightly. llvm-svn: 242081
2015-07-14 06:58:19 +08:00
// XXSLDWI could be replaced by a general permute with one of three
// permute control vectors (for shift values 1, 2, 3). However,
// VPERM has a more restrictive register class.
case PPC::XXSLDWI:
[PPC64LE] Remove unnecessary swaps from lane-insensitive vector computations This patch adds a new SSA MI pass that runs on little-endian PPC64 code with VSX enabled. Loads and stores of 4x32 and 2x64 vectors without alignment constraints are accomplished for little-endian using lxvd2x/xxswapd and xxswapd/stxvd2x. The existence of the additional xxswapd instructions hurts performance in comparison with big-endian code, but they are necessary in the general case to support correct semantics. However, the general case does not apply to most vector code. Many vector instructions are lane-insensitive; they do not "care" which lanes the parallel computations are performed within, provided that the resulting data is stored into the correct locations. Thus this pass looks for computations that perform only lane-insensitive operations, and remove the unnecessary swaps from loads and stores in such computations. Future improvements will allow computations using certain lane-sensitive operations to also be optimized in this manner, by modifying the lane-sensitive operations to account for the permuted order of the lanes. However, this patch only adds the infrastructure to permit this; no lane-sensitive operations are optimized at this time. This code is heavily exercised by the various vectorizing applications in the projects/test-suite tree. For the time being, I have only added one simple test case to demonstrate what the pass is doing. Although it is quite simple, it provides coverage for much of the code, including the special case handling of copies and subreg-to-reg operations feeding the swaps. I plan to add additional tests in the future as I fill in more of the "special handling" code. Two existing tests were affected, because they expected the swaps to be present, but they are now removed. llvm-svn: 235910
2015-04-28 03:57:34 +08:00
case PPC::XXSPLTW:
break;
}
}
}
if (RelevantFunction) {
DEBUG(dbgs() << "Swap vector when first built\n\n");
dumpSwapVector();
}
return RelevantFunction;
}
// Add an entry to the swap vector and swap map, and make a
// singleton equivalence class for the entry.
int PPCVSXSwapRemoval::addSwapEntry(MachineInstr *MI,
PPCVSXSwapEntry& SwapEntry) {
SwapEntry.VSEMI = MI;
SwapEntry.VSEId = SwapVector.size();
SwapVector.push_back(SwapEntry);
EC->insert(SwapEntry.VSEId);
SwapMap[MI] = SwapEntry.VSEId;
return SwapEntry.VSEId;
}
// This is used to find the "true" source register for an
// XXPERMDI instruction, since MachineCSE does not handle the
// "copy-like" operations (Copy and SubregToReg). Returns
// the original SrcReg unless it is the target of a copy-like
// operation, in which case we chain backwards through all
// such operations to the ultimate source register. If a
// physical register is encountered, we stop the search and
// flag the swap entry indicated by VecIdx (the original
[PPC64LE] Remove implicit-subreg restriction from VSX swap removal In r241285, I removed the SUBREG_TO_REG restriction from VSX swap removal, determining that this was overly conservative. We have another form of the same restriction in that we check for the presence of implicit subregs in vector operations. As with SUBREG_TO_REG for partial register conversions, an implicit subreg is safe in and of itself, provided no other operation makes a lane-sensitive assumption about the result. This patch removes that restriction, by removing the HasImplicitSubreg flag and all code that relies on it. I've added a test case that fails to optimize before this patch is applied, and optimizes properly with the patch. Test based on a report from Anton Blanchard. llvm-svn: 241290
2015-07-03 03:01:22 +08:00
// XXPERMDI) as mentioning a physical register.
[PPC64LE] Remove unnecessary swaps from lane-insensitive vector computations This patch adds a new SSA MI pass that runs on little-endian PPC64 code with VSX enabled. Loads and stores of 4x32 and 2x64 vectors without alignment constraints are accomplished for little-endian using lxvd2x/xxswapd and xxswapd/stxvd2x. The existence of the additional xxswapd instructions hurts performance in comparison with big-endian code, but they are necessary in the general case to support correct semantics. However, the general case does not apply to most vector code. Many vector instructions are lane-insensitive; they do not "care" which lanes the parallel computations are performed within, provided that the resulting data is stored into the correct locations. Thus this pass looks for computations that perform only lane-insensitive operations, and remove the unnecessary swaps from loads and stores in such computations. Future improvements will allow computations using certain lane-sensitive operations to also be optimized in this manner, by modifying the lane-sensitive operations to account for the permuted order of the lanes. However, this patch only adds the infrastructure to permit this; no lane-sensitive operations are optimized at this time. This code is heavily exercised by the various vectorizing applications in the projects/test-suite tree. For the time being, I have only added one simple test case to demonstrate what the pass is doing. Although it is quite simple, it provides coverage for much of the code, including the special case handling of copies and subreg-to-reg operations feeding the swaps. I plan to add additional tests in the future as I fill in more of the "special handling" code. Two existing tests were affected, because they expected the swaps to be present, but they are now removed. llvm-svn: 235910
2015-04-28 03:57:34 +08:00
unsigned PPCVSXSwapRemoval::lookThruCopyLike(unsigned SrcReg,
unsigned VecIdx) {
MachineInstr *MI = MRI->getVRegDef(SrcReg);
if (!MI->isCopyLike())
return SrcReg;
[PPC64LE] Remove implicit-subreg restriction from VSX swap removal In r241285, I removed the SUBREG_TO_REG restriction from VSX swap removal, determining that this was overly conservative. We have another form of the same restriction in that we check for the presence of implicit subregs in vector operations. As with SUBREG_TO_REG for partial register conversions, an implicit subreg is safe in and of itself, provided no other operation makes a lane-sensitive assumption about the result. This patch removes that restriction, by removing the HasImplicitSubreg flag and all code that relies on it. I've added a test case that fails to optimize before this patch is applied, and optimizes properly with the patch. Test based on a report from Anton Blanchard. llvm-svn: 241290
2015-07-03 03:01:22 +08:00
unsigned CopySrcReg;
if (MI->isCopy())
[PPC64LE] Remove unnecessary swaps from lane-insensitive vector computations This patch adds a new SSA MI pass that runs on little-endian PPC64 code with VSX enabled. Loads and stores of 4x32 and 2x64 vectors without alignment constraints are accomplished for little-endian using lxvd2x/xxswapd and xxswapd/stxvd2x. The existence of the additional xxswapd instructions hurts performance in comparison with big-endian code, but they are necessary in the general case to support correct semantics. However, the general case does not apply to most vector code. Many vector instructions are lane-insensitive; they do not "care" which lanes the parallel computations are performed within, provided that the resulting data is stored into the correct locations. Thus this pass looks for computations that perform only lane-insensitive operations, and remove the unnecessary swaps from loads and stores in such computations. Future improvements will allow computations using certain lane-sensitive operations to also be optimized in this manner, by modifying the lane-sensitive operations to account for the permuted order of the lanes. However, this patch only adds the infrastructure to permit this; no lane-sensitive operations are optimized at this time. This code is heavily exercised by the various vectorizing applications in the projects/test-suite tree. For the time being, I have only added one simple test case to demonstrate what the pass is doing. Although it is quite simple, it provides coverage for much of the code, including the special case handling of copies and subreg-to-reg operations feeding the swaps. I plan to add additional tests in the future as I fill in more of the "special handling" code. Two existing tests were affected, because they expected the swaps to be present, but they are now removed. llvm-svn: 235910
2015-04-28 03:57:34 +08:00
CopySrcReg = MI->getOperand(1).getReg();
[PPC64LE] Remove implicit-subreg restriction from VSX swap removal In r241285, I removed the SUBREG_TO_REG restriction from VSX swap removal, determining that this was overly conservative. We have another form of the same restriction in that we check for the presence of implicit subregs in vector operations. As with SUBREG_TO_REG for partial register conversions, an implicit subreg is safe in and of itself, provided no other operation makes a lane-sensitive assumption about the result. This patch removes that restriction, by removing the HasImplicitSubreg flag and all code that relies on it. I've added a test case that fails to optimize before this patch is applied, and optimizes properly with the patch. Test based on a report from Anton Blanchard. llvm-svn: 241290
2015-07-03 03:01:22 +08:00
else {
[PPC64LE] Remove unnecessary swaps from lane-insensitive vector computations This patch adds a new SSA MI pass that runs on little-endian PPC64 code with VSX enabled. Loads and stores of 4x32 and 2x64 vectors without alignment constraints are accomplished for little-endian using lxvd2x/xxswapd and xxswapd/stxvd2x. The existence of the additional xxswapd instructions hurts performance in comparison with big-endian code, but they are necessary in the general case to support correct semantics. However, the general case does not apply to most vector code. Many vector instructions are lane-insensitive; they do not "care" which lanes the parallel computations are performed within, provided that the resulting data is stored into the correct locations. Thus this pass looks for computations that perform only lane-insensitive operations, and remove the unnecessary swaps from loads and stores in such computations. Future improvements will allow computations using certain lane-sensitive operations to also be optimized in this manner, by modifying the lane-sensitive operations to account for the permuted order of the lanes. However, this patch only adds the infrastructure to permit this; no lane-sensitive operations are optimized at this time. This code is heavily exercised by the various vectorizing applications in the projects/test-suite tree. For the time being, I have only added one simple test case to demonstrate what the pass is doing. Although it is quite simple, it provides coverage for much of the code, including the special case handling of copies and subreg-to-reg operations feeding the swaps. I plan to add additional tests in the future as I fill in more of the "special handling" code. Two existing tests were affected, because they expected the swaps to be present, but they are now removed. llvm-svn: 235910
2015-04-28 03:57:34 +08:00
assert(MI->isSubregToReg() && "bad opcode for lookThruCopyLike");
CopySrcReg = MI->getOperand(2).getReg();
}
if (!TargetRegisterInfo::isVirtualRegister(CopySrcReg)) {
[PPC64LE] More vector swap optimization TLC This makes one substantive change and a few stylistic changes to the VSX swap optimization pass. The substantive change is to permit LXSDX and LXSSPX instructions to participate in swap optimization computations. The previous change to insert a swap following a SUBREG_TO_REG widening operation makes this almost trivial. I experimented with also permitting STXSDX and STXSSPX instructions. This can be done using similar techniques: we could insert a swap prior to a narrowing COPY operation, and then permit these stores to participate. I prototyped this, but discovered that the pattern of a narrowing COPY followed by an STXSDX does not occur in any of our test-suite code. So instead, I added commentary indicating that this could be done. Other TLC: - I changed SH_COPYSCALAR to SH_COPYWIDEN to more clearly indicate the direction of the copy. - I factored the insertion of swap instructions into a separate function. Finally, I added a new test case to check that the scalar-to-vector loads are working properly with swap optimization. llvm-svn: 242838
2015-07-22 05:40:17 +08:00
if (!isScalarVecReg(CopySrcReg))
SwapVector[VecIdx].MentionsPhysVR = 1;
[PPC64LE] Remove unnecessary swaps from lane-insensitive vector computations This patch adds a new SSA MI pass that runs on little-endian PPC64 code with VSX enabled. Loads and stores of 4x32 and 2x64 vectors without alignment constraints are accomplished for little-endian using lxvd2x/xxswapd and xxswapd/stxvd2x. The existence of the additional xxswapd instructions hurts performance in comparison with big-endian code, but they are necessary in the general case to support correct semantics. However, the general case does not apply to most vector code. Many vector instructions are lane-insensitive; they do not "care" which lanes the parallel computations are performed within, provided that the resulting data is stored into the correct locations. Thus this pass looks for computations that perform only lane-insensitive operations, and remove the unnecessary swaps from loads and stores in such computations. Future improvements will allow computations using certain lane-sensitive operations to also be optimized in this manner, by modifying the lane-sensitive operations to account for the permuted order of the lanes. However, this patch only adds the infrastructure to permit this; no lane-sensitive operations are optimized at this time. This code is heavily exercised by the various vectorizing applications in the projects/test-suite tree. For the time being, I have only added one simple test case to demonstrate what the pass is doing. Although it is quite simple, it provides coverage for much of the code, including the special case handling of copies and subreg-to-reg operations feeding the swaps. I plan to add additional tests in the future as I fill in more of the "special handling" code. Two existing tests were affected, because they expected the swaps to be present, but they are now removed. llvm-svn: 235910
2015-04-28 03:57:34 +08:00
return CopySrcReg;
}
return lookThruCopyLike(CopySrcReg, VecIdx);
}
// Generate equivalence classes for related computations (webs) by
// def-use relationships of virtual registers. Mention of a physical
// register terminates the generation of equivalence classes as this
// indicates a use of a parameter, definition of a return value, use
// of a value returned from a call, or definition of a parameter to a
// call. Computations with physical register mentions are flagged
// as such so their containing webs will not be optimized.
void PPCVSXSwapRemoval::formWebs() {
DEBUG(dbgs() << "\n*** Forming webs for swap removal ***\n\n");
for (unsigned EntryIdx = 0; EntryIdx < SwapVector.size(); ++EntryIdx) {
MachineInstr *MI = SwapVector[EntryIdx].VSEMI;
DEBUG(dbgs() << "\n" << SwapVector[EntryIdx].VSEId << " ");
DEBUG(MI->dump());
// It's sufficient to walk vector uses and join them to their unique
[PPC64LE] More improvements to VSX swap optimization This patch allows VSX swap optimization to succeed more frequently. Specifically, it is concerned with common code sequences that occur when copying a scalar floating-point value to a vector register. This patch currently handles cases where the floating-point value is already in a register, but does not yet handle loads (such as via an LXSDX scalar floating-point VSX load). That will be dealt with later. A typical case is when a scalar value comes in as a floating-point parameter. The value is copied into a virtual VSFRC register, and then a sequence of SUBREG_TO_REG and/or COPY operations will convert it to a full vector register of the class required by the context. If this vector register is then used as part of a lane-permuted computation, the original scalar value will be in the wrong lane. We can fix this by adding a swap operation following any widening SUBREG_TO_REG operation. Additional COPY operations may be needed around the swap operation in order to keep register assignment happy, but these are pro forma operations that will be removed by coalescing. If a scalar value is otherwise directly referenced in a computation (such as by one of the many XS* vector-scalar operations), we currently disable swap optimization. These operations are lane-sensitive by definition. A MentionsPartialVR flag is added for use in each swap table entry that mentions a scalar floating-point register without having special handling defined. A common idiom for PPC64LE is to convert a double-precision scalar to a vector by performing a splat operation. This ensures that the value can be referenced as V[0], as it would be for big endian, whereas just converting the scalar to a vector with a SUBREG_TO_REG operation leaves this value only in V[1]. A doubleword splat operation is one form of an XXPERMDI instruction, which takes one doubleword from a first operand and another doubleword from a second operand, with a two-bit selector operand indicating which doublewords are chosen. In the general case, an XXPERMDI can be permitted in a lane-swapped region provided that it is properly transformed to select the corresponding swapped values. This transformation is to reverse the order of the two input operands, and to reverse and complement the bits of the selector operand (derivation left as an exercise to the reader ;). A new test case that exercises the scalar-to-vector and generalized XXPERMDI transformations is added as CodeGen/PowerPC/swaps-le-5.ll. The patch also requires a change to CodeGen/PowerPC/swaps-le-3.ll to use CHECK-DAG instead of CHECK for two independent instructions that now appear in reverse order. There are two small unrelated changes that are added with this patch. First, the XXSLDWI instruction was incorrectly omitted from the list of lane-sensitive instructions; this is now fixed. Second, I observed that the same webs were being rejected over and over again for different reasons. Since it's sufficient to reject a web only once, I added a check for this to speed up the compilation time slightly. llvm-svn: 242081
2015-07-14 06:58:19 +08:00
// definitions. In addition, check full vector register operands
// for physical regs. We exclude partial-vector register operands
// because we can handle them if copied to a full vector.
[PPC64LE] Remove unnecessary swaps from lane-insensitive vector computations This patch adds a new SSA MI pass that runs on little-endian PPC64 code with VSX enabled. Loads and stores of 4x32 and 2x64 vectors without alignment constraints are accomplished for little-endian using lxvd2x/xxswapd and xxswapd/stxvd2x. The existence of the additional xxswapd instructions hurts performance in comparison with big-endian code, but they are necessary in the general case to support correct semantics. However, the general case does not apply to most vector code. Many vector instructions are lane-insensitive; they do not "care" which lanes the parallel computations are performed within, provided that the resulting data is stored into the correct locations. Thus this pass looks for computations that perform only lane-insensitive operations, and remove the unnecessary swaps from loads and stores in such computations. Future improvements will allow computations using certain lane-sensitive operations to also be optimized in this manner, by modifying the lane-sensitive operations to account for the permuted order of the lanes. However, this patch only adds the infrastructure to permit this; no lane-sensitive operations are optimized at this time. This code is heavily exercised by the various vectorizing applications in the projects/test-suite tree. For the time being, I have only added one simple test case to demonstrate what the pass is doing. Although it is quite simple, it provides coverage for much of the code, including the special case handling of copies and subreg-to-reg operations feeding the swaps. I plan to add additional tests in the future as I fill in more of the "special handling" code. Two existing tests were affected, because they expected the swaps to be present, but they are now removed. llvm-svn: 235910
2015-04-28 03:57:34 +08:00
for (const MachineOperand &MO : MI->operands()) {
if (!MO.isReg())
continue;
unsigned Reg = MO.getReg();
[PPC64LE] More improvements to VSX swap optimization This patch allows VSX swap optimization to succeed more frequently. Specifically, it is concerned with common code sequences that occur when copying a scalar floating-point value to a vector register. This patch currently handles cases where the floating-point value is already in a register, but does not yet handle loads (such as via an LXSDX scalar floating-point VSX load). That will be dealt with later. A typical case is when a scalar value comes in as a floating-point parameter. The value is copied into a virtual VSFRC register, and then a sequence of SUBREG_TO_REG and/or COPY operations will convert it to a full vector register of the class required by the context. If this vector register is then used as part of a lane-permuted computation, the original scalar value will be in the wrong lane. We can fix this by adding a swap operation following any widening SUBREG_TO_REG operation. Additional COPY operations may be needed around the swap operation in order to keep register assignment happy, but these are pro forma operations that will be removed by coalescing. If a scalar value is otherwise directly referenced in a computation (such as by one of the many XS* vector-scalar operations), we currently disable swap optimization. These operations are lane-sensitive by definition. A MentionsPartialVR flag is added for use in each swap table entry that mentions a scalar floating-point register without having special handling defined. A common idiom for PPC64LE is to convert a double-precision scalar to a vector by performing a splat operation. This ensures that the value can be referenced as V[0], as it would be for big endian, whereas just converting the scalar to a vector with a SUBREG_TO_REG operation leaves this value only in V[1]. A doubleword splat operation is one form of an XXPERMDI instruction, which takes one doubleword from a first operand and another doubleword from a second operand, with a two-bit selector operand indicating which doublewords are chosen. In the general case, an XXPERMDI can be permitted in a lane-swapped region provided that it is properly transformed to select the corresponding swapped values. This transformation is to reverse the order of the two input operands, and to reverse and complement the bits of the selector operand (derivation left as an exercise to the reader ;). A new test case that exercises the scalar-to-vector and generalized XXPERMDI transformations is added as CodeGen/PowerPC/swaps-le-5.ll. The patch also requires a change to CodeGen/PowerPC/swaps-le-3.ll to use CHECK-DAG instead of CHECK for two independent instructions that now appear in reverse order. There are two small unrelated changes that are added with this patch. First, the XXSLDWI instruction was incorrectly omitted from the list of lane-sensitive instructions; this is now fixed. Second, I observed that the same webs were being rejected over and over again for different reasons. Since it's sufficient to reject a web only once, I added a check for this to speed up the compilation time slightly. llvm-svn: 242081
2015-07-14 06:58:19 +08:00
if (!isVecReg(Reg) && !isScalarVecReg(Reg))
[PPC64LE] Remove unnecessary swaps from lane-insensitive vector computations This patch adds a new SSA MI pass that runs on little-endian PPC64 code with VSX enabled. Loads and stores of 4x32 and 2x64 vectors without alignment constraints are accomplished for little-endian using lxvd2x/xxswapd and xxswapd/stxvd2x. The existence of the additional xxswapd instructions hurts performance in comparison with big-endian code, but they are necessary in the general case to support correct semantics. However, the general case does not apply to most vector code. Many vector instructions are lane-insensitive; they do not "care" which lanes the parallel computations are performed within, provided that the resulting data is stored into the correct locations. Thus this pass looks for computations that perform only lane-insensitive operations, and remove the unnecessary swaps from loads and stores in such computations. Future improvements will allow computations using certain lane-sensitive operations to also be optimized in this manner, by modifying the lane-sensitive operations to account for the permuted order of the lanes. However, this patch only adds the infrastructure to permit this; no lane-sensitive operations are optimized at this time. This code is heavily exercised by the various vectorizing applications in the projects/test-suite tree. For the time being, I have only added one simple test case to demonstrate what the pass is doing. Although it is quite simple, it provides coverage for much of the code, including the special case handling of copies and subreg-to-reg operations feeding the swaps. I plan to add additional tests in the future as I fill in more of the "special handling" code. Two existing tests were affected, because they expected the swaps to be present, but they are now removed. llvm-svn: 235910
2015-04-28 03:57:34 +08:00
continue;
if (!TargetRegisterInfo::isVirtualRegister(Reg)) {
[PPC64LE] More improvements to VSX swap optimization This patch allows VSX swap optimization to succeed more frequently. Specifically, it is concerned with common code sequences that occur when copying a scalar floating-point value to a vector register. This patch currently handles cases where the floating-point value is already in a register, but does not yet handle loads (such as via an LXSDX scalar floating-point VSX load). That will be dealt with later. A typical case is when a scalar value comes in as a floating-point parameter. The value is copied into a virtual VSFRC register, and then a sequence of SUBREG_TO_REG and/or COPY operations will convert it to a full vector register of the class required by the context. If this vector register is then used as part of a lane-permuted computation, the original scalar value will be in the wrong lane. We can fix this by adding a swap operation following any widening SUBREG_TO_REG operation. Additional COPY operations may be needed around the swap operation in order to keep register assignment happy, but these are pro forma operations that will be removed by coalescing. If a scalar value is otherwise directly referenced in a computation (such as by one of the many XS* vector-scalar operations), we currently disable swap optimization. These operations are lane-sensitive by definition. A MentionsPartialVR flag is added for use in each swap table entry that mentions a scalar floating-point register without having special handling defined. A common idiom for PPC64LE is to convert a double-precision scalar to a vector by performing a splat operation. This ensures that the value can be referenced as V[0], as it would be for big endian, whereas just converting the scalar to a vector with a SUBREG_TO_REG operation leaves this value only in V[1]. A doubleword splat operation is one form of an XXPERMDI instruction, which takes one doubleword from a first operand and another doubleword from a second operand, with a two-bit selector operand indicating which doublewords are chosen. In the general case, an XXPERMDI can be permitted in a lane-swapped region provided that it is properly transformed to select the corresponding swapped values. This transformation is to reverse the order of the two input operands, and to reverse and complement the bits of the selector operand (derivation left as an exercise to the reader ;). A new test case that exercises the scalar-to-vector and generalized XXPERMDI transformations is added as CodeGen/PowerPC/swaps-le-5.ll. The patch also requires a change to CodeGen/PowerPC/swaps-le-3.ll to use CHECK-DAG instead of CHECK for two independent instructions that now appear in reverse order. There are two small unrelated changes that are added with this patch. First, the XXSLDWI instruction was incorrectly omitted from the list of lane-sensitive instructions; this is now fixed. Second, I observed that the same webs were being rejected over and over again for different reasons. Since it's sufficient to reject a web only once, I added a check for this to speed up the compilation time slightly. llvm-svn: 242081
2015-07-14 06:58:19 +08:00
if (!(MI->isCopy() && isScalarVecReg(Reg)))
SwapVector[EntryIdx].MentionsPhysVR = 1;
[PPC64LE] Remove unnecessary swaps from lane-insensitive vector computations This patch adds a new SSA MI pass that runs on little-endian PPC64 code with VSX enabled. Loads and stores of 4x32 and 2x64 vectors without alignment constraints are accomplished for little-endian using lxvd2x/xxswapd and xxswapd/stxvd2x. The existence of the additional xxswapd instructions hurts performance in comparison with big-endian code, but they are necessary in the general case to support correct semantics. However, the general case does not apply to most vector code. Many vector instructions are lane-insensitive; they do not "care" which lanes the parallel computations are performed within, provided that the resulting data is stored into the correct locations. Thus this pass looks for computations that perform only lane-insensitive operations, and remove the unnecessary swaps from loads and stores in such computations. Future improvements will allow computations using certain lane-sensitive operations to also be optimized in this manner, by modifying the lane-sensitive operations to account for the permuted order of the lanes. However, this patch only adds the infrastructure to permit this; no lane-sensitive operations are optimized at this time. This code is heavily exercised by the various vectorizing applications in the projects/test-suite tree. For the time being, I have only added one simple test case to demonstrate what the pass is doing. Although it is quite simple, it provides coverage for much of the code, including the special case handling of copies and subreg-to-reg operations feeding the swaps. I plan to add additional tests in the future as I fill in more of the "special handling" code. Two existing tests were affected, because they expected the swaps to be present, but they are now removed. llvm-svn: 235910
2015-04-28 03:57:34 +08:00
continue;
}
if (!MO.isUse())
continue;
MachineInstr* DefMI = MRI->getVRegDef(Reg);
assert(SwapMap.find(DefMI) != SwapMap.end() &&
"Inconsistency: def of vector reg not found in swap map!");
int DefIdx = SwapMap[DefMI];
(void)EC->unionSets(SwapVector[DefIdx].VSEId,
SwapVector[EntryIdx].VSEId);
DEBUG(dbgs() << format("Unioning %d with %d\n", SwapVector[DefIdx].VSEId,
SwapVector[EntryIdx].VSEId));
DEBUG(dbgs() << " Def: ");
DEBUG(DefMI->dump());
}
}
}
// Walk the swap vector entries looking for conditions that prevent their
// containing computations from being optimized. When such conditions are
// found, mark the representative of the computation's equivalence class
// as rejected.
void PPCVSXSwapRemoval::recordUnoptimizableWebs() {
DEBUG(dbgs() << "\n*** Rejecting webs for swap removal ***\n\n");
for (unsigned EntryIdx = 0; EntryIdx < SwapVector.size(); ++EntryIdx) {
int Repr = EC->getLeaderValue(SwapVector[EntryIdx].VSEId);
[PPC64LE] More improvements to VSX swap optimization This patch allows VSX swap optimization to succeed more frequently. Specifically, it is concerned with common code sequences that occur when copying a scalar floating-point value to a vector register. This patch currently handles cases where the floating-point value is already in a register, but does not yet handle loads (such as via an LXSDX scalar floating-point VSX load). That will be dealt with later. A typical case is when a scalar value comes in as a floating-point parameter. The value is copied into a virtual VSFRC register, and then a sequence of SUBREG_TO_REG and/or COPY operations will convert it to a full vector register of the class required by the context. If this vector register is then used as part of a lane-permuted computation, the original scalar value will be in the wrong lane. We can fix this by adding a swap operation following any widening SUBREG_TO_REG operation. Additional COPY operations may be needed around the swap operation in order to keep register assignment happy, but these are pro forma operations that will be removed by coalescing. If a scalar value is otherwise directly referenced in a computation (such as by one of the many XS* vector-scalar operations), we currently disable swap optimization. These operations are lane-sensitive by definition. A MentionsPartialVR flag is added for use in each swap table entry that mentions a scalar floating-point register without having special handling defined. A common idiom for PPC64LE is to convert a double-precision scalar to a vector by performing a splat operation. This ensures that the value can be referenced as V[0], as it would be for big endian, whereas just converting the scalar to a vector with a SUBREG_TO_REG operation leaves this value only in V[1]. A doubleword splat operation is one form of an XXPERMDI instruction, which takes one doubleword from a first operand and another doubleword from a second operand, with a two-bit selector operand indicating which doublewords are chosen. In the general case, an XXPERMDI can be permitted in a lane-swapped region provided that it is properly transformed to select the corresponding swapped values. This transformation is to reverse the order of the two input operands, and to reverse and complement the bits of the selector operand (derivation left as an exercise to the reader ;). A new test case that exercises the scalar-to-vector and generalized XXPERMDI transformations is added as CodeGen/PowerPC/swaps-le-5.ll. The patch also requires a change to CodeGen/PowerPC/swaps-le-3.ll to use CHECK-DAG instead of CHECK for two independent instructions that now appear in reverse order. There are two small unrelated changes that are added with this patch. First, the XXSLDWI instruction was incorrectly omitted from the list of lane-sensitive instructions; this is now fixed. Second, I observed that the same webs were being rejected over and over again for different reasons. Since it's sufficient to reject a web only once, I added a check for this to speed up the compilation time slightly. llvm-svn: 242081
2015-07-14 06:58:19 +08:00
// If representative is already rejected, don't waste further time.
if (SwapVector[Repr].WebRejected)
continue;
// Reject webs containing mentions of physical or partial registers, or
// containing operations that we don't know how to handle in a lane-
// permuted region.
[PPC64LE] Remove unnecessary swaps from lane-insensitive vector computations This patch adds a new SSA MI pass that runs on little-endian PPC64 code with VSX enabled. Loads and stores of 4x32 and 2x64 vectors without alignment constraints are accomplished for little-endian using lxvd2x/xxswapd and xxswapd/stxvd2x. The existence of the additional xxswapd instructions hurts performance in comparison with big-endian code, but they are necessary in the general case to support correct semantics. However, the general case does not apply to most vector code. Many vector instructions are lane-insensitive; they do not "care" which lanes the parallel computations are performed within, provided that the resulting data is stored into the correct locations. Thus this pass looks for computations that perform only lane-insensitive operations, and remove the unnecessary swaps from loads and stores in such computations. Future improvements will allow computations using certain lane-sensitive operations to also be optimized in this manner, by modifying the lane-sensitive operations to account for the permuted order of the lanes. However, this patch only adds the infrastructure to permit this; no lane-sensitive operations are optimized at this time. This code is heavily exercised by the various vectorizing applications in the projects/test-suite tree. For the time being, I have only added one simple test case to demonstrate what the pass is doing. Although it is quite simple, it provides coverage for much of the code, including the special case handling of copies and subreg-to-reg operations feeding the swaps. I plan to add additional tests in the future as I fill in more of the "special handling" code. Two existing tests were affected, because they expected the swaps to be present, but they are now removed. llvm-svn: 235910
2015-04-28 03:57:34 +08:00
if (SwapVector[EntryIdx].MentionsPhysVR ||
[PPC64LE] More improvements to VSX swap optimization This patch allows VSX swap optimization to succeed more frequently. Specifically, it is concerned with common code sequences that occur when copying a scalar floating-point value to a vector register. This patch currently handles cases where the floating-point value is already in a register, but does not yet handle loads (such as via an LXSDX scalar floating-point VSX load). That will be dealt with later. A typical case is when a scalar value comes in as a floating-point parameter. The value is copied into a virtual VSFRC register, and then a sequence of SUBREG_TO_REG and/or COPY operations will convert it to a full vector register of the class required by the context. If this vector register is then used as part of a lane-permuted computation, the original scalar value will be in the wrong lane. We can fix this by adding a swap operation following any widening SUBREG_TO_REG operation. Additional COPY operations may be needed around the swap operation in order to keep register assignment happy, but these are pro forma operations that will be removed by coalescing. If a scalar value is otherwise directly referenced in a computation (such as by one of the many XS* vector-scalar operations), we currently disable swap optimization. These operations are lane-sensitive by definition. A MentionsPartialVR flag is added for use in each swap table entry that mentions a scalar floating-point register without having special handling defined. A common idiom for PPC64LE is to convert a double-precision scalar to a vector by performing a splat operation. This ensures that the value can be referenced as V[0], as it would be for big endian, whereas just converting the scalar to a vector with a SUBREG_TO_REG operation leaves this value only in V[1]. A doubleword splat operation is one form of an XXPERMDI instruction, which takes one doubleword from a first operand and another doubleword from a second operand, with a two-bit selector operand indicating which doublewords are chosen. In the general case, an XXPERMDI can be permitted in a lane-swapped region provided that it is properly transformed to select the corresponding swapped values. This transformation is to reverse the order of the two input operands, and to reverse and complement the bits of the selector operand (derivation left as an exercise to the reader ;). A new test case that exercises the scalar-to-vector and generalized XXPERMDI transformations is added as CodeGen/PowerPC/swaps-le-5.ll. The patch also requires a change to CodeGen/PowerPC/swaps-le-3.ll to use CHECK-DAG instead of CHECK for two independent instructions that now appear in reverse order. There are two small unrelated changes that are added with this patch. First, the XXSLDWI instruction was incorrectly omitted from the list of lane-sensitive instructions; this is now fixed. Second, I observed that the same webs were being rejected over and over again for different reasons. Since it's sufficient to reject a web only once, I added a check for this to speed up the compilation time slightly. llvm-svn: 242081
2015-07-14 06:58:19 +08:00
SwapVector[EntryIdx].MentionsPartialVR ||
[PPC64LE] Remove unnecessary swaps from lane-insensitive vector computations This patch adds a new SSA MI pass that runs on little-endian PPC64 code with VSX enabled. Loads and stores of 4x32 and 2x64 vectors without alignment constraints are accomplished for little-endian using lxvd2x/xxswapd and xxswapd/stxvd2x. The existence of the additional xxswapd instructions hurts performance in comparison with big-endian code, but they are necessary in the general case to support correct semantics. However, the general case does not apply to most vector code. Many vector instructions are lane-insensitive; they do not "care" which lanes the parallel computations are performed within, provided that the resulting data is stored into the correct locations. Thus this pass looks for computations that perform only lane-insensitive operations, and remove the unnecessary swaps from loads and stores in such computations. Future improvements will allow computations using certain lane-sensitive operations to also be optimized in this manner, by modifying the lane-sensitive operations to account for the permuted order of the lanes. However, this patch only adds the infrastructure to permit this; no lane-sensitive operations are optimized at this time. This code is heavily exercised by the various vectorizing applications in the projects/test-suite tree. For the time being, I have only added one simple test case to demonstrate what the pass is doing. Although it is quite simple, it provides coverage for much of the code, including the special case handling of copies and subreg-to-reg operations feeding the swaps. I plan to add additional tests in the future as I fill in more of the "special handling" code. Two existing tests were affected, because they expected the swaps to be present, but they are now removed. llvm-svn: 235910
2015-04-28 03:57:34 +08:00
!(SwapVector[EntryIdx].IsSwappable || SwapVector[EntryIdx].IsSwap)) {
SwapVector[Repr].WebRejected = 1;
DEBUG(dbgs() <<
[PPC64LE] More vector swap optimization TLC This makes one substantive change and a few stylistic changes to the VSX swap optimization pass. The substantive change is to permit LXSDX and LXSSPX instructions to participate in swap optimization computations. The previous change to insert a swap following a SUBREG_TO_REG widening operation makes this almost trivial. I experimented with also permitting STXSDX and STXSSPX instructions. This can be done using similar techniques: we could insert a swap prior to a narrowing COPY operation, and then permit these stores to participate. I prototyped this, but discovered that the pattern of a narrowing COPY followed by an STXSDX does not occur in any of our test-suite code. So instead, I added commentary indicating that this could be done. Other TLC: - I changed SH_COPYSCALAR to SH_COPYWIDEN to more clearly indicate the direction of the copy. - I factored the insertion of swap instructions into a separate function. Finally, I added a new test case to check that the scalar-to-vector loads are working properly with swap optimization. llvm-svn: 242838
2015-07-22 05:40:17 +08:00
format("Web %d rejected for physreg, partial reg, or not "
"swap[pable]\n", Repr));
[PPC64LE] Remove unnecessary swaps from lane-insensitive vector computations This patch adds a new SSA MI pass that runs on little-endian PPC64 code with VSX enabled. Loads and stores of 4x32 and 2x64 vectors without alignment constraints are accomplished for little-endian using lxvd2x/xxswapd and xxswapd/stxvd2x. The existence of the additional xxswapd instructions hurts performance in comparison with big-endian code, but they are necessary in the general case to support correct semantics. However, the general case does not apply to most vector code. Many vector instructions are lane-insensitive; they do not "care" which lanes the parallel computations are performed within, provided that the resulting data is stored into the correct locations. Thus this pass looks for computations that perform only lane-insensitive operations, and remove the unnecessary swaps from loads and stores in such computations. Future improvements will allow computations using certain lane-sensitive operations to also be optimized in this manner, by modifying the lane-sensitive operations to account for the permuted order of the lanes. However, this patch only adds the infrastructure to permit this; no lane-sensitive operations are optimized at this time. This code is heavily exercised by the various vectorizing applications in the projects/test-suite tree. For the time being, I have only added one simple test case to demonstrate what the pass is doing. Although it is quite simple, it provides coverage for much of the code, including the special case handling of copies and subreg-to-reg operations feeding the swaps. I plan to add additional tests in the future as I fill in more of the "special handling" code. Two existing tests were affected, because they expected the swaps to be present, but they are now removed. llvm-svn: 235910
2015-04-28 03:57:34 +08:00
DEBUG(dbgs() << " in " << EntryIdx << ": ");
DEBUG(SwapVector[EntryIdx].VSEMI->dump());
DEBUG(dbgs() << "\n");
}
// Reject webs than contain swapping loads that feed something other
// than a swap instruction.
else if (SwapVector[EntryIdx].IsLoad && SwapVector[EntryIdx].IsSwap) {
MachineInstr *MI = SwapVector[EntryIdx].VSEMI;
unsigned DefReg = MI->getOperand(0).getReg();
// We skip debug instructions in the analysis. (Note that debug
// location information is still maintained by this optimization
// because it remains on the LXVD2X and STXVD2X instructions after
// the XXPERMDIs are removed.)
for (MachineInstr &UseMI : MRI->use_nodbg_instructions(DefReg)) {
int UseIdx = SwapMap[&UseMI];
if (!SwapVector[UseIdx].IsSwap || SwapVector[UseIdx].IsLoad ||
SwapVector[UseIdx].IsStore) {
SwapVector[Repr].WebRejected = 1;
DEBUG(dbgs() <<
format("Web %d rejected for load not feeding swap\n", Repr));
DEBUG(dbgs() << " def " << EntryIdx << ": ");
DEBUG(MI->dump());
DEBUG(dbgs() << " use " << UseIdx << ": ");
DEBUG(UseMI.dump());
DEBUG(dbgs() << "\n");
}
}
[PPC64LE] More improvements to VSX swap optimization This patch allows VSX swap optimization to succeed more frequently. Specifically, it is concerned with common code sequences that occur when copying a scalar floating-point value to a vector register. This patch currently handles cases where the floating-point value is already in a register, but does not yet handle loads (such as via an LXSDX scalar floating-point VSX load). That will be dealt with later. A typical case is when a scalar value comes in as a floating-point parameter. The value is copied into a virtual VSFRC register, and then a sequence of SUBREG_TO_REG and/or COPY operations will convert it to a full vector register of the class required by the context. If this vector register is then used as part of a lane-permuted computation, the original scalar value will be in the wrong lane. We can fix this by adding a swap operation following any widening SUBREG_TO_REG operation. Additional COPY operations may be needed around the swap operation in order to keep register assignment happy, but these are pro forma operations that will be removed by coalescing. If a scalar value is otherwise directly referenced in a computation (such as by one of the many XS* vector-scalar operations), we currently disable swap optimization. These operations are lane-sensitive by definition. A MentionsPartialVR flag is added for use in each swap table entry that mentions a scalar floating-point register without having special handling defined. A common idiom for PPC64LE is to convert a double-precision scalar to a vector by performing a splat operation. This ensures that the value can be referenced as V[0], as it would be for big endian, whereas just converting the scalar to a vector with a SUBREG_TO_REG operation leaves this value only in V[1]. A doubleword splat operation is one form of an XXPERMDI instruction, which takes one doubleword from a first operand and another doubleword from a second operand, with a two-bit selector operand indicating which doublewords are chosen. In the general case, an XXPERMDI can be permitted in a lane-swapped region provided that it is properly transformed to select the corresponding swapped values. This transformation is to reverse the order of the two input operands, and to reverse and complement the bits of the selector operand (derivation left as an exercise to the reader ;). A new test case that exercises the scalar-to-vector and generalized XXPERMDI transformations is added as CodeGen/PowerPC/swaps-le-5.ll. The patch also requires a change to CodeGen/PowerPC/swaps-le-3.ll to use CHECK-DAG instead of CHECK for two independent instructions that now appear in reverse order. There are two small unrelated changes that are added with this patch. First, the XXSLDWI instruction was incorrectly omitted from the list of lane-sensitive instructions; this is now fixed. Second, I observed that the same webs were being rejected over and over again for different reasons. Since it's sufficient to reject a web only once, I added a check for this to speed up the compilation time slightly. llvm-svn: 242081
2015-07-14 06:58:19 +08:00
// Reject webs that contain swapping stores that are fed by something
[PPC64LE] Remove unnecessary swaps from lane-insensitive vector computations This patch adds a new SSA MI pass that runs on little-endian PPC64 code with VSX enabled. Loads and stores of 4x32 and 2x64 vectors without alignment constraints are accomplished for little-endian using lxvd2x/xxswapd and xxswapd/stxvd2x. The existence of the additional xxswapd instructions hurts performance in comparison with big-endian code, but they are necessary in the general case to support correct semantics. However, the general case does not apply to most vector code. Many vector instructions are lane-insensitive; they do not "care" which lanes the parallel computations are performed within, provided that the resulting data is stored into the correct locations. Thus this pass looks for computations that perform only lane-insensitive operations, and remove the unnecessary swaps from loads and stores in such computations. Future improvements will allow computations using certain lane-sensitive operations to also be optimized in this manner, by modifying the lane-sensitive operations to account for the permuted order of the lanes. However, this patch only adds the infrastructure to permit this; no lane-sensitive operations are optimized at this time. This code is heavily exercised by the various vectorizing applications in the projects/test-suite tree. For the time being, I have only added one simple test case to demonstrate what the pass is doing. Although it is quite simple, it provides coverage for much of the code, including the special case handling of copies and subreg-to-reg operations feeding the swaps. I plan to add additional tests in the future as I fill in more of the "special handling" code. Two existing tests were affected, because they expected the swaps to be present, but they are now removed. llvm-svn: 235910
2015-04-28 03:57:34 +08:00
// other than a swap instruction.
} else if (SwapVector[EntryIdx].IsStore && SwapVector[EntryIdx].IsSwap) {
MachineInstr *MI = SwapVector[EntryIdx].VSEMI;
unsigned UseReg = MI->getOperand(0).getReg();
MachineInstr *DefMI = MRI->getVRegDef(UseReg);
int DefIdx = SwapMap[DefMI];
if (!SwapVector[DefIdx].IsSwap || SwapVector[DefIdx].IsLoad ||
SwapVector[DefIdx].IsStore) {
SwapVector[Repr].WebRejected = 1;
DEBUG(dbgs() <<
format("Web %d rejected for store not fed by swap\n", Repr));
DEBUG(dbgs() << " def " << DefIdx << ": ");
DEBUG(DefMI->dump());
DEBUG(dbgs() << " use " << EntryIdx << ": ");
DEBUG(MI->dump());
DEBUG(dbgs() << "\n");
}
}
}
DEBUG(dbgs() << "Swap vector after web analysis:\n\n");
dumpSwapVector();
}
// Walk the swap vector entries looking for swaps fed by permuting loads
// and swaps that feed permuting stores. If the containing computation
// has not been marked rejected, mark each such swap for removal.
// (Removal is delayed in case optimization has disturbed the pattern,
// such that multiple loads feed the same swap, etc.)
void PPCVSXSwapRemoval::markSwapsForRemoval() {
DEBUG(dbgs() << "\n*** Marking swaps for removal ***\n\n");
for (unsigned EntryIdx = 0; EntryIdx < SwapVector.size(); ++EntryIdx) {
if (SwapVector[EntryIdx].IsLoad && SwapVector[EntryIdx].IsSwap) {
int Repr = EC->getLeaderValue(SwapVector[EntryIdx].VSEId);
if (!SwapVector[Repr].WebRejected) {
MachineInstr *MI = SwapVector[EntryIdx].VSEMI;
unsigned DefReg = MI->getOperand(0).getReg();
for (MachineInstr &UseMI : MRI->use_nodbg_instructions(DefReg)) {
int UseIdx = SwapMap[&UseMI];
SwapVector[UseIdx].WillRemove = 1;
DEBUG(dbgs() << "Marking swap fed by load for removal: ");
DEBUG(UseMI.dump());
}
}
} else if (SwapVector[EntryIdx].IsStore && SwapVector[EntryIdx].IsSwap) {
int Repr = EC->getLeaderValue(SwapVector[EntryIdx].VSEId);
if (!SwapVector[Repr].WebRejected) {
MachineInstr *MI = SwapVector[EntryIdx].VSEMI;
unsigned UseReg = MI->getOperand(0).getReg();
MachineInstr *DefMI = MRI->getVRegDef(UseReg);
int DefIdx = SwapMap[DefMI];
SwapVector[DefIdx].WillRemove = 1;
DEBUG(dbgs() << "Marking swap feeding store for removal: ");
DEBUG(DefMI->dump());
}
} else if (SwapVector[EntryIdx].IsSwappable &&
[PPC64LE] Adjust vector splats during VSX swap optimization The initial code drop for VSX swap optimization permitted the optimization only when all operations in a web of related computation are lane-insensitive. For some lane-sensitive operations, we can still permit the optimization provided that we make adjustments to those operations. This patch adds special handling for vector splats so that their presence doesn't kill the optimization. Vector splats are lane-sensitive since they identify by number a vector element to be used as the source of a splat. When swap optimizations take place, the desired vector element will move to the opposite doubleword of the quadword vector. We thus replace the index I by (I + N/2) % N, where N is the number of elements in the vector. A new test case is added to test that swap optimization succeeds when vector splats are present, and that the proper input element is used as the source of the splat. An ancillary change removes SH_BUILDVEC as one of the kinds of special handling that may be required by VSX swap optimization. From experience with GCC, I had expected to need some modifications for vector build operations, but I did not find that to be the case. llvm-svn: 236606
2015-05-06 23:40:46 +08:00
SwapVector[EntryIdx].SpecialHandling != 0) {
int Repr = EC->getLeaderValue(SwapVector[EntryIdx].VSEId);
if (!SwapVector[Repr].WebRejected)
handleSpecialSwappables(EntryIdx);
}
[PPC64LE] Remove unnecessary swaps from lane-insensitive vector computations This patch adds a new SSA MI pass that runs on little-endian PPC64 code with VSX enabled. Loads and stores of 4x32 and 2x64 vectors without alignment constraints are accomplished for little-endian using lxvd2x/xxswapd and xxswapd/stxvd2x. The existence of the additional xxswapd instructions hurts performance in comparison with big-endian code, but they are necessary in the general case to support correct semantics. However, the general case does not apply to most vector code. Many vector instructions are lane-insensitive; they do not "care" which lanes the parallel computations are performed within, provided that the resulting data is stored into the correct locations. Thus this pass looks for computations that perform only lane-insensitive operations, and remove the unnecessary swaps from loads and stores in such computations. Future improvements will allow computations using certain lane-sensitive operations to also be optimized in this manner, by modifying the lane-sensitive operations to account for the permuted order of the lanes. However, this patch only adds the infrastructure to permit this; no lane-sensitive operations are optimized at this time. This code is heavily exercised by the various vectorizing applications in the projects/test-suite tree. For the time being, I have only added one simple test case to demonstrate what the pass is doing. Although it is quite simple, it provides coverage for much of the code, including the special case handling of copies and subreg-to-reg operations feeding the swaps. I plan to add additional tests in the future as I fill in more of the "special handling" code. Two existing tests were affected, because they expected the swaps to be present, but they are now removed. llvm-svn: 235910
2015-04-28 03:57:34 +08:00
}
}
[PPC64LE] More vector swap optimization TLC This makes one substantive change and a few stylistic changes to the VSX swap optimization pass. The substantive change is to permit LXSDX and LXSSPX instructions to participate in swap optimization computations. The previous change to insert a swap following a SUBREG_TO_REG widening operation makes this almost trivial. I experimented with also permitting STXSDX and STXSSPX instructions. This can be done using similar techniques: we could insert a swap prior to a narrowing COPY operation, and then permit these stores to participate. I prototyped this, but discovered that the pattern of a narrowing COPY followed by an STXSDX does not occur in any of our test-suite code. So instead, I added commentary indicating that this could be done. Other TLC: - I changed SH_COPYSCALAR to SH_COPYWIDEN to more clearly indicate the direction of the copy. - I factored the insertion of swap instructions into a separate function. Finally, I added a new test case to check that the scalar-to-vector loads are working properly with swap optimization. llvm-svn: 242838
2015-07-22 05:40:17 +08:00
// Create an xxswapd instruction and insert it prior to the given point.
// MI is used to determine basic block and debug loc information.
// FIXME: When inserting a swap, we should check whether SrcReg is
// defined by another swap: SrcReg = XXPERMDI Reg, Reg, 2; If so,
// then instead we should generate a copy from Reg to DstReg.
void PPCVSXSwapRemoval::insertSwap(MachineInstr *MI,
MachineBasicBlock::iterator InsertPoint,
unsigned DstReg, unsigned SrcReg) {
BuildMI(*MI->getParent(), InsertPoint, MI->getDebugLoc(),
TII->get(PPC::XXPERMDI), DstReg)
.addReg(SrcReg)
.addReg(SrcReg)
.addImm(2);
}
[PPC64LE] Remove unnecessary swaps from lane-insensitive vector computations This patch adds a new SSA MI pass that runs on little-endian PPC64 code with VSX enabled. Loads and stores of 4x32 and 2x64 vectors without alignment constraints are accomplished for little-endian using lxvd2x/xxswapd and xxswapd/stxvd2x. The existence of the additional xxswapd instructions hurts performance in comparison with big-endian code, but they are necessary in the general case to support correct semantics. However, the general case does not apply to most vector code. Many vector instructions are lane-insensitive; they do not "care" which lanes the parallel computations are performed within, provided that the resulting data is stored into the correct locations. Thus this pass looks for computations that perform only lane-insensitive operations, and remove the unnecessary swaps from loads and stores in such computations. Future improvements will allow computations using certain lane-sensitive operations to also be optimized in this manner, by modifying the lane-sensitive operations to account for the permuted order of the lanes. However, this patch only adds the infrastructure to permit this; no lane-sensitive operations are optimized at this time. This code is heavily exercised by the various vectorizing applications in the projects/test-suite tree. For the time being, I have only added one simple test case to demonstrate what the pass is doing. Although it is quite simple, it provides coverage for much of the code, including the special case handling of copies and subreg-to-reg operations feeding the swaps. I plan to add additional tests in the future as I fill in more of the "special handling" code. Two existing tests were affected, because they expected the swaps to be present, but they are now removed. llvm-svn: 235910
2015-04-28 03:57:34 +08:00
// The identified swap entry requires special handling to allow its
// containing computation to be optimized. Perform that handling
// here.
[PPC64LE] More improvements to VSX swap optimization This patch allows VSX swap optimization to succeed more frequently. Specifically, it is concerned with common code sequences that occur when copying a scalar floating-point value to a vector register. This patch currently handles cases where the floating-point value is already in a register, but does not yet handle loads (such as via an LXSDX scalar floating-point VSX load). That will be dealt with later. A typical case is when a scalar value comes in as a floating-point parameter. The value is copied into a virtual VSFRC register, and then a sequence of SUBREG_TO_REG and/or COPY operations will convert it to a full vector register of the class required by the context. If this vector register is then used as part of a lane-permuted computation, the original scalar value will be in the wrong lane. We can fix this by adding a swap operation following any widening SUBREG_TO_REG operation. Additional COPY operations may be needed around the swap operation in order to keep register assignment happy, but these are pro forma operations that will be removed by coalescing. If a scalar value is otherwise directly referenced in a computation (such as by one of the many XS* vector-scalar operations), we currently disable swap optimization. These operations are lane-sensitive by definition. A MentionsPartialVR flag is added for use in each swap table entry that mentions a scalar floating-point register without having special handling defined. A common idiom for PPC64LE is to convert a double-precision scalar to a vector by performing a splat operation. This ensures that the value can be referenced as V[0], as it would be for big endian, whereas just converting the scalar to a vector with a SUBREG_TO_REG operation leaves this value only in V[1]. A doubleword splat operation is one form of an XXPERMDI instruction, which takes one doubleword from a first operand and another doubleword from a second operand, with a two-bit selector operand indicating which doublewords are chosen. In the general case, an XXPERMDI can be permitted in a lane-swapped region provided that it is properly transformed to select the corresponding swapped values. This transformation is to reverse the order of the two input operands, and to reverse and complement the bits of the selector operand (derivation left as an exercise to the reader ;). A new test case that exercises the scalar-to-vector and generalized XXPERMDI transformations is added as CodeGen/PowerPC/swaps-le-5.ll. The patch also requires a change to CodeGen/PowerPC/swaps-le-3.ll to use CHECK-DAG instead of CHECK for two independent instructions that now appear in reverse order. There are two small unrelated changes that are added with this patch. First, the XXSLDWI instruction was incorrectly omitted from the list of lane-sensitive instructions; this is now fixed. Second, I observed that the same webs were being rejected over and over again for different reasons. Since it's sufficient to reject a web only once, I added a check for this to speed up the compilation time slightly. llvm-svn: 242081
2015-07-14 06:58:19 +08:00
// FIXME: Additional opportunities will be phased in with subsequent
// patches.
[PPC64LE] Remove unnecessary swaps from lane-insensitive vector computations This patch adds a new SSA MI pass that runs on little-endian PPC64 code with VSX enabled. Loads and stores of 4x32 and 2x64 vectors without alignment constraints are accomplished for little-endian using lxvd2x/xxswapd and xxswapd/stxvd2x. The existence of the additional xxswapd instructions hurts performance in comparison with big-endian code, but they are necessary in the general case to support correct semantics. However, the general case does not apply to most vector code. Many vector instructions are lane-insensitive; they do not "care" which lanes the parallel computations are performed within, provided that the resulting data is stored into the correct locations. Thus this pass looks for computations that perform only lane-insensitive operations, and remove the unnecessary swaps from loads and stores in such computations. Future improvements will allow computations using certain lane-sensitive operations to also be optimized in this manner, by modifying the lane-sensitive operations to account for the permuted order of the lanes. However, this patch only adds the infrastructure to permit this; no lane-sensitive operations are optimized at this time. This code is heavily exercised by the various vectorizing applications in the projects/test-suite tree. For the time being, I have only added one simple test case to demonstrate what the pass is doing. Although it is quite simple, it provides coverage for much of the code, including the special case handling of copies and subreg-to-reg operations feeding the swaps. I plan to add additional tests in the future as I fill in more of the "special handling" code. Two existing tests were affected, because they expected the swaps to be present, but they are now removed. llvm-svn: 235910
2015-04-28 03:57:34 +08:00
void PPCVSXSwapRemoval::handleSpecialSwappables(int EntryIdx) {
[PPC64LE] Adjust vector splats during VSX swap optimization The initial code drop for VSX swap optimization permitted the optimization only when all operations in a web of related computation are lane-insensitive. For some lane-sensitive operations, we can still permit the optimization provided that we make adjustments to those operations. This patch adds special handling for vector splats so that their presence doesn't kill the optimization. Vector splats are lane-sensitive since they identify by number a vector element to be used as the source of a splat. When swap optimizations take place, the desired vector element will move to the opposite doubleword of the quadword vector. We thus replace the index I by (I + N/2) % N, where N is the number of elements in the vector. A new test case is added to test that swap optimization succeeds when vector splats are present, and that the proper input element is used as the source of the splat. An ancillary change removes SH_BUILDVEC as one of the kinds of special handling that may be required by VSX swap optimization. From experience with GCC, I had expected to need some modifications for vector build operations, but I did not find that to be the case. llvm-svn: 236606
2015-05-06 23:40:46 +08:00
switch (SwapVector[EntryIdx].SpecialHandling) {
default:
Convert assert(false) into llvm_unreachable where it makes sense. llvm-svn: 251266
2015-10-26 06:28:27 +08:00
llvm_unreachable("Unexpected special handling type");
[PPC64LE] Adjust vector splats during VSX swap optimization The initial code drop for VSX swap optimization permitted the optimization only when all operations in a web of related computation are lane-insensitive. For some lane-sensitive operations, we can still permit the optimization provided that we make adjustments to those operations. This patch adds special handling for vector splats so that their presence doesn't kill the optimization. Vector splats are lane-sensitive since they identify by number a vector element to be used as the source of a splat. When swap optimizations take place, the desired vector element will move to the opposite doubleword of the quadword vector. We thus replace the index I by (I + N/2) % N, where N is the number of elements in the vector. A new test case is added to test that swap optimization succeeds when vector splats are present, and that the proper input element is used as the source of the splat. An ancillary change removes SH_BUILDVEC as one of the kinds of special handling that may be required by VSX swap optimization. From experience with GCC, I had expected to need some modifications for vector build operations, but I did not find that to be the case. llvm-svn: 236606
2015-05-06 23:40:46 +08:00
// For splats based on an index into a vector, add N/2 modulo N
// to the index, where N is the number of vector elements.
case SHValues::SH_SPLAT: {
MachineInstr *MI = SwapVector[EntryIdx].VSEMI;
unsigned NElts;
DEBUG(dbgs() << "Changing splat: ");
DEBUG(MI->dump());
switch (MI->getOpcode()) {
default:
Convert assert(false) into llvm_unreachable where it makes sense. llvm-svn: 251266
2015-10-26 06:28:27 +08:00
llvm_unreachable("Unexpected splat opcode");
[PPC64LE] Adjust vector splats during VSX swap optimization The initial code drop for VSX swap optimization permitted the optimization only when all operations in a web of related computation are lane-insensitive. For some lane-sensitive operations, we can still permit the optimization provided that we make adjustments to those operations. This patch adds special handling for vector splats so that their presence doesn't kill the optimization. Vector splats are lane-sensitive since they identify by number a vector element to be used as the source of a splat. When swap optimizations take place, the desired vector element will move to the opposite doubleword of the quadword vector. We thus replace the index I by (I + N/2) % N, where N is the number of elements in the vector. A new test case is added to test that swap optimization succeeds when vector splats are present, and that the proper input element is used as the source of the splat. An ancillary change removes SH_BUILDVEC as one of the kinds of special handling that may be required by VSX swap optimization. From experience with GCC, I had expected to need some modifications for vector build operations, but I did not find that to be the case. llvm-svn: 236606
2015-05-06 23:40:46 +08:00
case PPC::VSPLTB: NElts = 16; break;
case PPC::VSPLTH: NElts = 8; break;
case PPC::VSPLTW: NElts = 4; break;
}
unsigned EltNo = MI->getOperand(1).getImm();
EltNo = (EltNo + NElts / 2) % NElts;
MI->getOperand(1).setImm(EltNo);
DEBUG(dbgs() << " Into: ");
DEBUG(MI->dump());
break;
}
[PPC64LE] More improvements to VSX swap optimization This patch allows VSX swap optimization to succeed more frequently. Specifically, it is concerned with common code sequences that occur when copying a scalar floating-point value to a vector register. This patch currently handles cases where the floating-point value is already in a register, but does not yet handle loads (such as via an LXSDX scalar floating-point VSX load). That will be dealt with later. A typical case is when a scalar value comes in as a floating-point parameter. The value is copied into a virtual VSFRC register, and then a sequence of SUBREG_TO_REG and/or COPY operations will convert it to a full vector register of the class required by the context. If this vector register is then used as part of a lane-permuted computation, the original scalar value will be in the wrong lane. We can fix this by adding a swap operation following any widening SUBREG_TO_REG operation. Additional COPY operations may be needed around the swap operation in order to keep register assignment happy, but these are pro forma operations that will be removed by coalescing. If a scalar value is otherwise directly referenced in a computation (such as by one of the many XS* vector-scalar operations), we currently disable swap optimization. These operations are lane-sensitive by definition. A MentionsPartialVR flag is added for use in each swap table entry that mentions a scalar floating-point register without having special handling defined. A common idiom for PPC64LE is to convert a double-precision scalar to a vector by performing a splat operation. This ensures that the value can be referenced as V[0], as it would be for big endian, whereas just converting the scalar to a vector with a SUBREG_TO_REG operation leaves this value only in V[1]. A doubleword splat operation is one form of an XXPERMDI instruction, which takes one doubleword from a first operand and another doubleword from a second operand, with a two-bit selector operand indicating which doublewords are chosen. In the general case, an XXPERMDI can be permitted in a lane-swapped region provided that it is properly transformed to select the corresponding swapped values. This transformation is to reverse the order of the two input operands, and to reverse and complement the bits of the selector operand (derivation left as an exercise to the reader ;). A new test case that exercises the scalar-to-vector and generalized XXPERMDI transformations is added as CodeGen/PowerPC/swaps-le-5.ll. The patch also requires a change to CodeGen/PowerPC/swaps-le-3.ll to use CHECK-DAG instead of CHECK for two independent instructions that now appear in reverse order. There are two small unrelated changes that are added with this patch. First, the XXSLDWI instruction was incorrectly omitted from the list of lane-sensitive instructions; this is now fixed. Second, I observed that the same webs were being rejected over and over again for different reasons. Since it's sufficient to reject a web only once, I added a check for this to speed up the compilation time slightly. llvm-svn: 242081
2015-07-14 06:58:19 +08:00
// For an XXPERMDI that isn't handled otherwise, we need to
// reverse the order of the operands. If the selector operand
// has a value of 0 or 3, we need to change it to 3 or 0,
// respectively. Otherwise we should leave it alone. (This
// is equivalent to reversing the two bits of the selector
// operand and complementing the result.)
case SHValues::SH_XXPERMDI: {
MachineInstr *MI = SwapVector[EntryIdx].VSEMI;
DEBUG(dbgs() << "Changing XXPERMDI: ");
DEBUG(MI->dump());
unsigned Selector = MI->getOperand(3).getImm();
if (Selector == 0 || Selector == 3)
Selector = 3 - Selector;
MI->getOperand(3).setImm(Selector);
unsigned Reg1 = MI->getOperand(1).getReg();
unsigned Reg2 = MI->getOperand(2).getReg();
MI->getOperand(1).setReg(Reg2);
MI->getOperand(2).setReg(Reg1);
DEBUG(dbgs() << " Into: ");
DEBUG(MI->dump());
break;
}
// For a copy from a scalar floating-point register to a vector
// register, removing swaps will leave the copied value in the
// wrong lane. Insert a swap following the copy to fix this.
[PPC64LE] More vector swap optimization TLC This makes one substantive change and a few stylistic changes to the VSX swap optimization pass. The substantive change is to permit LXSDX and LXSSPX instructions to participate in swap optimization computations. The previous change to insert a swap following a SUBREG_TO_REG widening operation makes this almost trivial. I experimented with also permitting STXSDX and STXSSPX instructions. This can be done using similar techniques: we could insert a swap prior to a narrowing COPY operation, and then permit these stores to participate. I prototyped this, but discovered that the pattern of a narrowing COPY followed by an STXSDX does not occur in any of our test-suite code. So instead, I added commentary indicating that this could be done. Other TLC: - I changed SH_COPYSCALAR to SH_COPYWIDEN to more clearly indicate the direction of the copy. - I factored the insertion of swap instructions into a separate function. Finally, I added a new test case to check that the scalar-to-vector loads are working properly with swap optimization. llvm-svn: 242838
2015-07-22 05:40:17 +08:00
case SHValues::SH_COPYWIDEN: {
[PPC64LE] More improvements to VSX swap optimization This patch allows VSX swap optimization to succeed more frequently. Specifically, it is concerned with common code sequences that occur when copying a scalar floating-point value to a vector register. This patch currently handles cases where the floating-point value is already in a register, but does not yet handle loads (such as via an LXSDX scalar floating-point VSX load). That will be dealt with later. A typical case is when a scalar value comes in as a floating-point parameter. The value is copied into a virtual VSFRC register, and then a sequence of SUBREG_TO_REG and/or COPY operations will convert it to a full vector register of the class required by the context. If this vector register is then used as part of a lane-permuted computation, the original scalar value will be in the wrong lane. We can fix this by adding a swap operation following any widening SUBREG_TO_REG operation. Additional COPY operations may be needed around the swap operation in order to keep register assignment happy, but these are pro forma operations that will be removed by coalescing. If a scalar value is otherwise directly referenced in a computation (such as by one of the many XS* vector-scalar operations), we currently disable swap optimization. These operations are lane-sensitive by definition. A MentionsPartialVR flag is added for use in each swap table entry that mentions a scalar floating-point register without having special handling defined. A common idiom for PPC64LE is to convert a double-precision scalar to a vector by performing a splat operation. This ensures that the value can be referenced as V[0], as it would be for big endian, whereas just converting the scalar to a vector with a SUBREG_TO_REG operation leaves this value only in V[1]. A doubleword splat operation is one form of an XXPERMDI instruction, which takes one doubleword from a first operand and another doubleword from a second operand, with a two-bit selector operand indicating which doublewords are chosen. In the general case, an XXPERMDI can be permitted in a lane-swapped region provided that it is properly transformed to select the corresponding swapped values. This transformation is to reverse the order of the two input operands, and to reverse and complement the bits of the selector operand (derivation left as an exercise to the reader ;). A new test case that exercises the scalar-to-vector and generalized XXPERMDI transformations is added as CodeGen/PowerPC/swaps-le-5.ll. The patch also requires a change to CodeGen/PowerPC/swaps-le-3.ll to use CHECK-DAG instead of CHECK for two independent instructions that now appear in reverse order. There are two small unrelated changes that are added with this patch. First, the XXSLDWI instruction was incorrectly omitted from the list of lane-sensitive instructions; this is now fixed. Second, I observed that the same webs were being rejected over and over again for different reasons. Since it's sufficient to reject a web only once, I added a check for this to speed up the compilation time slightly. llvm-svn: 242081
2015-07-14 06:58:19 +08:00
MachineInstr *MI = SwapVector[EntryIdx].VSEMI;
DEBUG(dbgs() << "Changing SUBREG_TO_REG: ");
DEBUG(MI->dump());
unsigned DstReg = MI->getOperand(0).getReg();
const TargetRegisterClass *DstRC = MRI->getRegClass(DstReg);
unsigned NewVReg = MRI->createVirtualRegister(DstRC);
MI->getOperand(0).setReg(NewVReg);
DEBUG(dbgs() << " Into: ");
DEBUG(MI->dump());
PowerPC: Don't use getNextNode() for insertion point Stop using `getNextNode()` to create an insertion point for machine instructions (at least, in this one place). Instead, use an iterator. As a drive-by, clean up dump statements to use iterator logic. The `getNextNode()` interface isn't actually supposed to work for insertion points; it's supposed to return `nullptr` if this is the last node. It's currently broken and will "happen" to work, but if we ever fix the function, we'll get some strange failures. llvm-svn: 249758
2015-10-09 06:20:37 +08:00
auto InsertPoint = ++MachineBasicBlock::iterator(MI);
[PPC64LE] More improvements to VSX swap optimization This patch allows VSX swap optimization to succeed more frequently. Specifically, it is concerned with common code sequences that occur when copying a scalar floating-point value to a vector register. This patch currently handles cases where the floating-point value is already in a register, but does not yet handle loads (such as via an LXSDX scalar floating-point VSX load). That will be dealt with later. A typical case is when a scalar value comes in as a floating-point parameter. The value is copied into a virtual VSFRC register, and then a sequence of SUBREG_TO_REG and/or COPY operations will convert it to a full vector register of the class required by the context. If this vector register is then used as part of a lane-permuted computation, the original scalar value will be in the wrong lane. We can fix this by adding a swap operation following any widening SUBREG_TO_REG operation. Additional COPY operations may be needed around the swap operation in order to keep register assignment happy, but these are pro forma operations that will be removed by coalescing. If a scalar value is otherwise directly referenced in a computation (such as by one of the many XS* vector-scalar operations), we currently disable swap optimization. These operations are lane-sensitive by definition. A MentionsPartialVR flag is added for use in each swap table entry that mentions a scalar floating-point register without having special handling defined. A common idiom for PPC64LE is to convert a double-precision scalar to a vector by performing a splat operation. This ensures that the value can be referenced as V[0], as it would be for big endian, whereas just converting the scalar to a vector with a SUBREG_TO_REG operation leaves this value only in V[1]. A doubleword splat operation is one form of an XXPERMDI instruction, which takes one doubleword from a first operand and another doubleword from a second operand, with a two-bit selector operand indicating which doublewords are chosen. In the general case, an XXPERMDI can be permitted in a lane-swapped region provided that it is properly transformed to select the corresponding swapped values. This transformation is to reverse the order of the two input operands, and to reverse and complement the bits of the selector operand (derivation left as an exercise to the reader ;). A new test case that exercises the scalar-to-vector and generalized XXPERMDI transformations is added as CodeGen/PowerPC/swaps-le-5.ll. The patch also requires a change to CodeGen/PowerPC/swaps-le-3.ll to use CHECK-DAG instead of CHECK for two independent instructions that now appear in reverse order. There are two small unrelated changes that are added with this patch. First, the XXSLDWI instruction was incorrectly omitted from the list of lane-sensitive instructions; this is now fixed. Second, I observed that the same webs were being rejected over and over again for different reasons. Since it's sufficient to reject a web only once, I added a check for this to speed up the compilation time slightly. llvm-svn: 242081
2015-07-14 06:58:19 +08:00
// Note that an XXPERMDI requires a VSRC, so if the SUBREG_TO_REG
// is copying to a VRRC, we need to be careful to avoid a register
// assignment problem. In this case we must copy from VRRC to VSRC
// prior to the swap, and from VSRC to VRRC following the swap.
// Coalescing will usually remove all this mess.
if (DstRC == &PPC::VRRCRegClass) {
unsigned VSRCTmp1 = MRI->createVirtualRegister(&PPC::VSRCRegClass);
unsigned VSRCTmp2 = MRI->createVirtualRegister(&PPC::VSRCRegClass);
BuildMI(*MI->getParent(), InsertPoint, MI->getDebugLoc(),
TII->get(PPC::COPY), VSRCTmp1)
.addReg(NewVReg);
PowerPC: Don't use getNextNode() for insertion point Stop using `getNextNode()` to create an insertion point for machine instructions (at least, in this one place). Instead, use an iterator. As a drive-by, clean up dump statements to use iterator logic. The `getNextNode()` interface isn't actually supposed to work for insertion points; it's supposed to return `nullptr` if this is the last node. It's currently broken and will "happen" to work, but if we ever fix the function, we'll get some strange failures. llvm-svn: 249758
2015-10-09 06:20:37 +08:00
DEBUG(std::prev(InsertPoint)->dump());
[PPC64LE] More improvements to VSX swap optimization This patch allows VSX swap optimization to succeed more frequently. Specifically, it is concerned with common code sequences that occur when copying a scalar floating-point value to a vector register. This patch currently handles cases where the floating-point value is already in a register, but does not yet handle loads (such as via an LXSDX scalar floating-point VSX load). That will be dealt with later. A typical case is when a scalar value comes in as a floating-point parameter. The value is copied into a virtual VSFRC register, and then a sequence of SUBREG_TO_REG and/or COPY operations will convert it to a full vector register of the class required by the context. If this vector register is then used as part of a lane-permuted computation, the original scalar value will be in the wrong lane. We can fix this by adding a swap operation following any widening SUBREG_TO_REG operation. Additional COPY operations may be needed around the swap operation in order to keep register assignment happy, but these are pro forma operations that will be removed by coalescing. If a scalar value is otherwise directly referenced in a computation (such as by one of the many XS* vector-scalar operations), we currently disable swap optimization. These operations are lane-sensitive by definition. A MentionsPartialVR flag is added for use in each swap table entry that mentions a scalar floating-point register without having special handling defined. A common idiom for PPC64LE is to convert a double-precision scalar to a vector by performing a splat operation. This ensures that the value can be referenced as V[0], as it would be for big endian, whereas just converting the scalar to a vector with a SUBREG_TO_REG operation leaves this value only in V[1]. A doubleword splat operation is one form of an XXPERMDI instruction, which takes one doubleword from a first operand and another doubleword from a second operand, with a two-bit selector operand indicating which doublewords are chosen. In the general case, an XXPERMDI can be permitted in a lane-swapped region provided that it is properly transformed to select the corresponding swapped values. This transformation is to reverse the order of the two input operands, and to reverse and complement the bits of the selector operand (derivation left as an exercise to the reader ;). A new test case that exercises the scalar-to-vector and generalized XXPERMDI transformations is added as CodeGen/PowerPC/swaps-le-5.ll. The patch also requires a change to CodeGen/PowerPC/swaps-le-3.ll to use CHECK-DAG instead of CHECK for two independent instructions that now appear in reverse order. There are two small unrelated changes that are added with this patch. First, the XXSLDWI instruction was incorrectly omitted from the list of lane-sensitive instructions; this is now fixed. Second, I observed that the same webs were being rejected over and over again for different reasons. Since it's sufficient to reject a web only once, I added a check for this to speed up the compilation time slightly. llvm-svn: 242081
2015-07-14 06:58:19 +08:00
[PPC64LE] More vector swap optimization TLC This makes one substantive change and a few stylistic changes to the VSX swap optimization pass. The substantive change is to permit LXSDX and LXSSPX instructions to participate in swap optimization computations. The previous change to insert a swap following a SUBREG_TO_REG widening operation makes this almost trivial. I experimented with also permitting STXSDX and STXSSPX instructions. This can be done using similar techniques: we could insert a swap prior to a narrowing COPY operation, and then permit these stores to participate. I prototyped this, but discovered that the pattern of a narrowing COPY followed by an STXSDX does not occur in any of our test-suite code. So instead, I added commentary indicating that this could be done. Other TLC: - I changed SH_COPYSCALAR to SH_COPYWIDEN to more clearly indicate the direction of the copy. - I factored the insertion of swap instructions into a separate function. Finally, I added a new test case to check that the scalar-to-vector loads are working properly with swap optimization. llvm-svn: 242838
2015-07-22 05:40:17 +08:00
insertSwap(MI, InsertPoint, VSRCTmp2, VSRCTmp1);
PowerPC: Don't use getNextNode() for insertion point Stop using `getNextNode()` to create an insertion point for machine instructions (at least, in this one place). Instead, use an iterator. As a drive-by, clean up dump statements to use iterator logic. The `getNextNode()` interface isn't actually supposed to work for insertion points; it's supposed to return `nullptr` if this is the last node. It's currently broken and will "happen" to work, but if we ever fix the function, we'll get some strange failures. llvm-svn: 249758
2015-10-09 06:20:37 +08:00
DEBUG(std::prev(InsertPoint)->dump());
[PPC64LE] More improvements to VSX swap optimization This patch allows VSX swap optimization to succeed more frequently. Specifically, it is concerned with common code sequences that occur when copying a scalar floating-point value to a vector register. This patch currently handles cases where the floating-point value is already in a register, but does not yet handle loads (such as via an LXSDX scalar floating-point VSX load). That will be dealt with later. A typical case is when a scalar value comes in as a floating-point parameter. The value is copied into a virtual VSFRC register, and then a sequence of SUBREG_TO_REG and/or COPY operations will convert it to a full vector register of the class required by the context. If this vector register is then used as part of a lane-permuted computation, the original scalar value will be in the wrong lane. We can fix this by adding a swap operation following any widening SUBREG_TO_REG operation. Additional COPY operations may be needed around the swap operation in order to keep register assignment happy, but these are pro forma operations that will be removed by coalescing. If a scalar value is otherwise directly referenced in a computation (such as by one of the many XS* vector-scalar operations), we currently disable swap optimization. These operations are lane-sensitive by definition. A MentionsPartialVR flag is added for use in each swap table entry that mentions a scalar floating-point register without having special handling defined. A common idiom for PPC64LE is to convert a double-precision scalar to a vector by performing a splat operation. This ensures that the value can be referenced as V[0], as it would be for big endian, whereas just converting the scalar to a vector with a SUBREG_TO_REG operation leaves this value only in V[1]. A doubleword splat operation is one form of an XXPERMDI instruction, which takes one doubleword from a first operand and another doubleword from a second operand, with a two-bit selector operand indicating which doublewords are chosen. In the general case, an XXPERMDI can be permitted in a lane-swapped region provided that it is properly transformed to select the corresponding swapped values. This transformation is to reverse the order of the two input operands, and to reverse and complement the bits of the selector operand (derivation left as an exercise to the reader ;). A new test case that exercises the scalar-to-vector and generalized XXPERMDI transformations is added as CodeGen/PowerPC/swaps-le-5.ll. The patch also requires a change to CodeGen/PowerPC/swaps-le-3.ll to use CHECK-DAG instead of CHECK for two independent instructions that now appear in reverse order. There are two small unrelated changes that are added with this patch. First, the XXSLDWI instruction was incorrectly omitted from the list of lane-sensitive instructions; this is now fixed. Second, I observed that the same webs were being rejected over and over again for different reasons. Since it's sufficient to reject a web only once, I added a check for this to speed up the compilation time slightly. llvm-svn: 242081
2015-07-14 06:58:19 +08:00
BuildMI(*MI->getParent(), InsertPoint, MI->getDebugLoc(),
TII->get(PPC::COPY), DstReg)
.addReg(VSRCTmp2);
PowerPC: Don't use getNextNode() for insertion point Stop using `getNextNode()` to create an insertion point for machine instructions (at least, in this one place). Instead, use an iterator. As a drive-by, clean up dump statements to use iterator logic. The `getNextNode()` interface isn't actually supposed to work for insertion points; it's supposed to return `nullptr` if this is the last node. It's currently broken and will "happen" to work, but if we ever fix the function, we'll get some strange failures. llvm-svn: 249758
2015-10-09 06:20:37 +08:00
DEBUG(std::prev(InsertPoint)->dump());
[PPC64LE] More improvements to VSX swap optimization This patch allows VSX swap optimization to succeed more frequently. Specifically, it is concerned with common code sequences that occur when copying a scalar floating-point value to a vector register. This patch currently handles cases where the floating-point value is already in a register, but does not yet handle loads (such as via an LXSDX scalar floating-point VSX load). That will be dealt with later. A typical case is when a scalar value comes in as a floating-point parameter. The value is copied into a virtual VSFRC register, and then a sequence of SUBREG_TO_REG and/or COPY operations will convert it to a full vector register of the class required by the context. If this vector register is then used as part of a lane-permuted computation, the original scalar value will be in the wrong lane. We can fix this by adding a swap operation following any widening SUBREG_TO_REG operation. Additional COPY operations may be needed around the swap operation in order to keep register assignment happy, but these are pro forma operations that will be removed by coalescing. If a scalar value is otherwise directly referenced in a computation (such as by one of the many XS* vector-scalar operations), we currently disable swap optimization. These operations are lane-sensitive by definition. A MentionsPartialVR flag is added for use in each swap table entry that mentions a scalar floating-point register without having special handling defined. A common idiom for PPC64LE is to convert a double-precision scalar to a vector by performing a splat operation. This ensures that the value can be referenced as V[0], as it would be for big endian, whereas just converting the scalar to a vector with a SUBREG_TO_REG operation leaves this value only in V[1]. A doubleword splat operation is one form of an XXPERMDI instruction, which takes one doubleword from a first operand and another doubleword from a second operand, with a two-bit selector operand indicating which doublewords are chosen. In the general case, an XXPERMDI can be permitted in a lane-swapped region provided that it is properly transformed to select the corresponding swapped values. This transformation is to reverse the order of the two input operands, and to reverse and complement the bits of the selector operand (derivation left as an exercise to the reader ;). A new test case that exercises the scalar-to-vector and generalized XXPERMDI transformations is added as CodeGen/PowerPC/swaps-le-5.ll. The patch also requires a change to CodeGen/PowerPC/swaps-le-3.ll to use CHECK-DAG instead of CHECK for two independent instructions that now appear in reverse order. There are two small unrelated changes that are added with this patch. First, the XXSLDWI instruction was incorrectly omitted from the list of lane-sensitive instructions; this is now fixed. Second, I observed that the same webs were being rejected over and over again for different reasons. Since it's sufficient to reject a web only once, I added a check for this to speed up the compilation time slightly. llvm-svn: 242081
2015-07-14 06:58:19 +08:00
} else {
[PPC64LE] More vector swap optimization TLC This makes one substantive change and a few stylistic changes to the VSX swap optimization pass. The substantive change is to permit LXSDX and LXSSPX instructions to participate in swap optimization computations. The previous change to insert a swap following a SUBREG_TO_REG widening operation makes this almost trivial. I experimented with also permitting STXSDX and STXSSPX instructions. This can be done using similar techniques: we could insert a swap prior to a narrowing COPY operation, and then permit these stores to participate. I prototyped this, but discovered that the pattern of a narrowing COPY followed by an STXSDX does not occur in any of our test-suite code. So instead, I added commentary indicating that this could be done. Other TLC: - I changed SH_COPYSCALAR to SH_COPYWIDEN to more clearly indicate the direction of the copy. - I factored the insertion of swap instructions into a separate function. Finally, I added a new test case to check that the scalar-to-vector loads are working properly with swap optimization. llvm-svn: 242838
2015-07-22 05:40:17 +08:00
insertSwap(MI, InsertPoint, DstReg, NewVReg);
PowerPC: Don't use getNextNode() for insertion point Stop using `getNextNode()` to create an insertion point for machine instructions (at least, in this one place). Instead, use an iterator. As a drive-by, clean up dump statements to use iterator logic. The `getNextNode()` interface isn't actually supposed to work for insertion points; it's supposed to return `nullptr` if this is the last node. It's currently broken and will "happen" to work, but if we ever fix the function, we'll get some strange failures. llvm-svn: 249758
2015-10-09 06:20:37 +08:00
DEBUG(std::prev(InsertPoint)->dump());
[PPC64LE] More improvements to VSX swap optimization This patch allows VSX swap optimization to succeed more frequently. Specifically, it is concerned with common code sequences that occur when copying a scalar floating-point value to a vector register. This patch currently handles cases where the floating-point value is already in a register, but does not yet handle loads (such as via an LXSDX scalar floating-point VSX load). That will be dealt with later. A typical case is when a scalar value comes in as a floating-point parameter. The value is copied into a virtual VSFRC register, and then a sequence of SUBREG_TO_REG and/or COPY operations will convert it to a full vector register of the class required by the context. If this vector register is then used as part of a lane-permuted computation, the original scalar value will be in the wrong lane. We can fix this by adding a swap operation following any widening SUBREG_TO_REG operation. Additional COPY operations may be needed around the swap operation in order to keep register assignment happy, but these are pro forma operations that will be removed by coalescing. If a scalar value is otherwise directly referenced in a computation (such as by one of the many XS* vector-scalar operations), we currently disable swap optimization. These operations are lane-sensitive by definition. A MentionsPartialVR flag is added for use in each swap table entry that mentions a scalar floating-point register without having special handling defined. A common idiom for PPC64LE is to convert a double-precision scalar to a vector by performing a splat operation. This ensures that the value can be referenced as V[0], as it would be for big endian, whereas just converting the scalar to a vector with a SUBREG_TO_REG operation leaves this value only in V[1]. A doubleword splat operation is one form of an XXPERMDI instruction, which takes one doubleword from a first operand and another doubleword from a second operand, with a two-bit selector operand indicating which doublewords are chosen. In the general case, an XXPERMDI can be permitted in a lane-swapped region provided that it is properly transformed to select the corresponding swapped values. This transformation is to reverse the order of the two input operands, and to reverse and complement the bits of the selector operand (derivation left as an exercise to the reader ;). A new test case that exercises the scalar-to-vector and generalized XXPERMDI transformations is added as CodeGen/PowerPC/swaps-le-5.ll. The patch also requires a change to CodeGen/PowerPC/swaps-le-3.ll to use CHECK-DAG instead of CHECK for two independent instructions that now appear in reverse order. There are two small unrelated changes that are added with this patch. First, the XXSLDWI instruction was incorrectly omitted from the list of lane-sensitive instructions; this is now fixed. Second, I observed that the same webs were being rejected over and over again for different reasons. Since it's sufficient to reject a web only once, I added a check for this to speed up the compilation time slightly. llvm-svn: 242081
2015-07-14 06:58:19 +08:00
}
break;
}
[PPC64LE] Adjust vector splats during VSX swap optimization The initial code drop for VSX swap optimization permitted the optimization only when all operations in a web of related computation are lane-insensitive. For some lane-sensitive operations, we can still permit the optimization provided that we make adjustments to those operations. This patch adds special handling for vector splats so that their presence doesn't kill the optimization. Vector splats are lane-sensitive since they identify by number a vector element to be used as the source of a splat. When swap optimizations take place, the desired vector element will move to the opposite doubleword of the quadword vector. We thus replace the index I by (I + N/2) % N, where N is the number of elements in the vector. A new test case is added to test that swap optimization succeeds when vector splats are present, and that the proper input element is used as the source of the splat. An ancillary change removes SH_BUILDVEC as one of the kinds of special handling that may be required by VSX swap optimization. From experience with GCC, I had expected to need some modifications for vector build operations, but I did not find that to be the case. llvm-svn: 236606
2015-05-06 23:40:46 +08:00
}
[PPC64LE] Remove unnecessary swaps from lane-insensitive vector computations This patch adds a new SSA MI pass that runs on little-endian PPC64 code with VSX enabled. Loads and stores of 4x32 and 2x64 vectors without alignment constraints are accomplished for little-endian using lxvd2x/xxswapd and xxswapd/stxvd2x. The existence of the additional xxswapd instructions hurts performance in comparison with big-endian code, but they are necessary in the general case to support correct semantics. However, the general case does not apply to most vector code. Many vector instructions are lane-insensitive; they do not "care" which lanes the parallel computations are performed within, provided that the resulting data is stored into the correct locations. Thus this pass looks for computations that perform only lane-insensitive operations, and remove the unnecessary swaps from loads and stores in such computations. Future improvements will allow computations using certain lane-sensitive operations to also be optimized in this manner, by modifying the lane-sensitive operations to account for the permuted order of the lanes. However, this patch only adds the infrastructure to permit this; no lane-sensitive operations are optimized at this time. This code is heavily exercised by the various vectorizing applications in the projects/test-suite tree. For the time being, I have only added one simple test case to demonstrate what the pass is doing. Although it is quite simple, it provides coverage for much of the code, including the special case handling of copies and subreg-to-reg operations feeding the swaps. I plan to add additional tests in the future as I fill in more of the "special handling" code. Two existing tests were affected, because they expected the swaps to be present, but they are now removed. llvm-svn: 235910
2015-04-28 03:57:34 +08:00
}
// Walk the swap vector and replace each entry marked for removal with
// a copy operation.
bool PPCVSXSwapRemoval::removeSwaps() {
DEBUG(dbgs() << "\n*** Removing swaps ***\n\n");
bool Changed = false;
for (unsigned EntryIdx = 0; EntryIdx < SwapVector.size(); ++EntryIdx) {
if (SwapVector[EntryIdx].WillRemove) {
Changed = true;
MachineInstr *MI = SwapVector[EntryIdx].VSEMI;
MachineBasicBlock *MBB = MI->getParent();
BuildMI(*MBB, MI, MI->getDebugLoc(),
TII->get(TargetOpcode::COPY), MI->getOperand(0).getReg())
.addOperand(MI->getOperand(1));
DEBUG(dbgs() << format("Replaced %d with copy: ",
SwapVector[EntryIdx].VSEId));
DEBUG(MI->dump());
MI->eraseFromParent();
}
}
return Changed;
}
// For debug purposes, dump the contents of the swap vector.
void PPCVSXSwapRemoval::dumpSwapVector() {
for (unsigned EntryIdx = 0; EntryIdx < SwapVector.size(); ++EntryIdx) {
MachineInstr *MI = SwapVector[EntryIdx].VSEMI;
int ID = SwapVector[EntryIdx].VSEId;
DEBUG(dbgs() << format("%6d", ID));
DEBUG(dbgs() << format("%6d", EC->getLeaderValue(ID)));
DEBUG(dbgs() << format(" BB#%3d", MI->getParent()->getNumber()));
DEBUG(dbgs() << format(" %14s ", TII->getName(MI->getOpcode())));
if (SwapVector[EntryIdx].IsLoad)
DEBUG(dbgs() << "load ");
if (SwapVector[EntryIdx].IsStore)
DEBUG(dbgs() << "store ");
if (SwapVector[EntryIdx].IsSwap)
DEBUG(dbgs() << "swap ");
if (SwapVector[EntryIdx].MentionsPhysVR)
DEBUG(dbgs() << "physreg ");
[PPC64LE] More improvements to VSX swap optimization This patch allows VSX swap optimization to succeed more frequently. Specifically, it is concerned with common code sequences that occur when copying a scalar floating-point value to a vector register. This patch currently handles cases where the floating-point value is already in a register, but does not yet handle loads (such as via an LXSDX scalar floating-point VSX load). That will be dealt with later. A typical case is when a scalar value comes in as a floating-point parameter. The value is copied into a virtual VSFRC register, and then a sequence of SUBREG_TO_REG and/or COPY operations will convert it to a full vector register of the class required by the context. If this vector register is then used as part of a lane-permuted computation, the original scalar value will be in the wrong lane. We can fix this by adding a swap operation following any widening SUBREG_TO_REG operation. Additional COPY operations may be needed around the swap operation in order to keep register assignment happy, but these are pro forma operations that will be removed by coalescing. If a scalar value is otherwise directly referenced in a computation (such as by one of the many XS* vector-scalar operations), we currently disable swap optimization. These operations are lane-sensitive by definition. A MentionsPartialVR flag is added for use in each swap table entry that mentions a scalar floating-point register without having special handling defined. A common idiom for PPC64LE is to convert a double-precision scalar to a vector by performing a splat operation. This ensures that the value can be referenced as V[0], as it would be for big endian, whereas just converting the scalar to a vector with a SUBREG_TO_REG operation leaves this value only in V[1]. A doubleword splat operation is one form of an XXPERMDI instruction, which takes one doubleword from a first operand and another doubleword from a second operand, with a two-bit selector operand indicating which doublewords are chosen. In the general case, an XXPERMDI can be permitted in a lane-swapped region provided that it is properly transformed to select the corresponding swapped values. This transformation is to reverse the order of the two input operands, and to reverse and complement the bits of the selector operand (derivation left as an exercise to the reader ;). A new test case that exercises the scalar-to-vector and generalized XXPERMDI transformations is added as CodeGen/PowerPC/swaps-le-5.ll. The patch also requires a change to CodeGen/PowerPC/swaps-le-3.ll to use CHECK-DAG instead of CHECK for two independent instructions that now appear in reverse order. There are two small unrelated changes that are added with this patch. First, the XXSLDWI instruction was incorrectly omitted from the list of lane-sensitive instructions; this is now fixed. Second, I observed that the same webs were being rejected over and over again for different reasons. Since it's sufficient to reject a web only once, I added a check for this to speed up the compilation time slightly. llvm-svn: 242081
2015-07-14 06:58:19 +08:00
if (SwapVector[EntryIdx].MentionsPartialVR)
DEBUG(dbgs() << "partialreg ");
[PPC64LE] Remove unnecessary swaps from lane-insensitive vector computations This patch adds a new SSA MI pass that runs on little-endian PPC64 code with VSX enabled. Loads and stores of 4x32 and 2x64 vectors without alignment constraints are accomplished for little-endian using lxvd2x/xxswapd and xxswapd/stxvd2x. The existence of the additional xxswapd instructions hurts performance in comparison with big-endian code, but they are necessary in the general case to support correct semantics. However, the general case does not apply to most vector code. Many vector instructions are lane-insensitive; they do not "care" which lanes the parallel computations are performed within, provided that the resulting data is stored into the correct locations. Thus this pass looks for computations that perform only lane-insensitive operations, and remove the unnecessary swaps from loads and stores in such computations. Future improvements will allow computations using certain lane-sensitive operations to also be optimized in this manner, by modifying the lane-sensitive operations to account for the permuted order of the lanes. However, this patch only adds the infrastructure to permit this; no lane-sensitive operations are optimized at this time. This code is heavily exercised by the various vectorizing applications in the projects/test-suite tree. For the time being, I have only added one simple test case to demonstrate what the pass is doing. Although it is quite simple, it provides coverage for much of the code, including the special case handling of copies and subreg-to-reg operations feeding the swaps. I plan to add additional tests in the future as I fill in more of the "special handling" code. Two existing tests were affected, because they expected the swaps to be present, but they are now removed. llvm-svn: 235910
2015-04-28 03:57:34 +08:00
if (SwapVector[EntryIdx].IsSwappable) {
DEBUG(dbgs() << "swappable ");
switch(SwapVector[EntryIdx].SpecialHandling) {
default:
DEBUG(dbgs() << "special:**unknown**");
break;
case SH_NONE:
break;
case SH_EXTRACT:
DEBUG(dbgs() << "special:extract ");
break;
case SH_INSERT:
DEBUG(dbgs() << "special:insert ");
break;
case SH_NOSWAP_LD:
DEBUG(dbgs() << "special:load ");
break;
case SH_NOSWAP_ST:
DEBUG(dbgs() << "special:store ");
break;
case SH_SPLAT:
DEBUG(dbgs() << "special:splat ");
break;
[PPC64LE] More improvements to VSX swap optimization This patch allows VSX swap optimization to succeed more frequently. Specifically, it is concerned with common code sequences that occur when copying a scalar floating-point value to a vector register. This patch currently handles cases where the floating-point value is already in a register, but does not yet handle loads (such as via an LXSDX scalar floating-point VSX load). That will be dealt with later. A typical case is when a scalar value comes in as a floating-point parameter. The value is copied into a virtual VSFRC register, and then a sequence of SUBREG_TO_REG and/or COPY operations will convert it to a full vector register of the class required by the context. If this vector register is then used as part of a lane-permuted computation, the original scalar value will be in the wrong lane. We can fix this by adding a swap operation following any widening SUBREG_TO_REG operation. Additional COPY operations may be needed around the swap operation in order to keep register assignment happy, but these are pro forma operations that will be removed by coalescing. If a scalar value is otherwise directly referenced in a computation (such as by one of the many XS* vector-scalar operations), we currently disable swap optimization. These operations are lane-sensitive by definition. A MentionsPartialVR flag is added for use in each swap table entry that mentions a scalar floating-point register without having special handling defined. A common idiom for PPC64LE is to convert a double-precision scalar to a vector by performing a splat operation. This ensures that the value can be referenced as V[0], as it would be for big endian, whereas just converting the scalar to a vector with a SUBREG_TO_REG operation leaves this value only in V[1]. A doubleword splat operation is one form of an XXPERMDI instruction, which takes one doubleword from a first operand and another doubleword from a second operand, with a two-bit selector operand indicating which doublewords are chosen. In the general case, an XXPERMDI can be permitted in a lane-swapped region provided that it is properly transformed to select the corresponding swapped values. This transformation is to reverse the order of the two input operands, and to reverse and complement the bits of the selector operand (derivation left as an exercise to the reader ;). A new test case that exercises the scalar-to-vector and generalized XXPERMDI transformations is added as CodeGen/PowerPC/swaps-le-5.ll. The patch also requires a change to CodeGen/PowerPC/swaps-le-3.ll to use CHECK-DAG instead of CHECK for two independent instructions that now appear in reverse order. There are two small unrelated changes that are added with this patch. First, the XXSLDWI instruction was incorrectly omitted from the list of lane-sensitive instructions; this is now fixed. Second, I observed that the same webs were being rejected over and over again for different reasons. Since it's sufficient to reject a web only once, I added a check for this to speed up the compilation time slightly. llvm-svn: 242081
2015-07-14 06:58:19 +08:00
case SH_XXPERMDI:
DEBUG(dbgs() << "special:xxpermdi ");
break;
[PPC64LE] More vector swap optimization TLC This makes one substantive change and a few stylistic changes to the VSX swap optimization pass. The substantive change is to permit LXSDX and LXSSPX instructions to participate in swap optimization computations. The previous change to insert a swap following a SUBREG_TO_REG widening operation makes this almost trivial. I experimented with also permitting STXSDX and STXSSPX instructions. This can be done using similar techniques: we could insert a swap prior to a narrowing COPY operation, and then permit these stores to participate. I prototyped this, but discovered that the pattern of a narrowing COPY followed by an STXSDX does not occur in any of our test-suite code. So instead, I added commentary indicating that this could be done. Other TLC: - I changed SH_COPYSCALAR to SH_COPYWIDEN to more clearly indicate the direction of the copy. - I factored the insertion of swap instructions into a separate function. Finally, I added a new test case to check that the scalar-to-vector loads are working properly with swap optimization. llvm-svn: 242838
2015-07-22 05:40:17 +08:00
case SH_COPYWIDEN:
DEBUG(dbgs() << "special:copywiden ");
[PPC64LE] More improvements to VSX swap optimization This patch allows VSX swap optimization to succeed more frequently. Specifically, it is concerned with common code sequences that occur when copying a scalar floating-point value to a vector register. This patch currently handles cases where the floating-point value is already in a register, but does not yet handle loads (such as via an LXSDX scalar floating-point VSX load). That will be dealt with later. A typical case is when a scalar value comes in as a floating-point parameter. The value is copied into a virtual VSFRC register, and then a sequence of SUBREG_TO_REG and/or COPY operations will convert it to a full vector register of the class required by the context. If this vector register is then used as part of a lane-permuted computation, the original scalar value will be in the wrong lane. We can fix this by adding a swap operation following any widening SUBREG_TO_REG operation. Additional COPY operations may be needed around the swap operation in order to keep register assignment happy, but these are pro forma operations that will be removed by coalescing. If a scalar value is otherwise directly referenced in a computation (such as by one of the many XS* vector-scalar operations), we currently disable swap optimization. These operations are lane-sensitive by definition. A MentionsPartialVR flag is added for use in each swap table entry that mentions a scalar floating-point register without having special handling defined. A common idiom for PPC64LE is to convert a double-precision scalar to a vector by performing a splat operation. This ensures that the value can be referenced as V[0], as it would be for big endian, whereas just converting the scalar to a vector with a SUBREG_TO_REG operation leaves this value only in V[1]. A doubleword splat operation is one form of an XXPERMDI instruction, which takes one doubleword from a first operand and another doubleword from a second operand, with a two-bit selector operand indicating which doublewords are chosen. In the general case, an XXPERMDI can be permitted in a lane-swapped region provided that it is properly transformed to select the corresponding swapped values. This transformation is to reverse the order of the two input operands, and to reverse and complement the bits of the selector operand (derivation left as an exercise to the reader ;). A new test case that exercises the scalar-to-vector and generalized XXPERMDI transformations is added as CodeGen/PowerPC/swaps-le-5.ll. The patch also requires a change to CodeGen/PowerPC/swaps-le-3.ll to use CHECK-DAG instead of CHECK for two independent instructions that now appear in reverse order. There are two small unrelated changes that are added with this patch. First, the XXSLDWI instruction was incorrectly omitted from the list of lane-sensitive instructions; this is now fixed. Second, I observed that the same webs were being rejected over and over again for different reasons. Since it's sufficient to reject a web only once, I added a check for this to speed up the compilation time slightly. llvm-svn: 242081
2015-07-14 06:58:19 +08:00
break;
[PPC64LE] Remove unnecessary swaps from lane-insensitive vector computations This patch adds a new SSA MI pass that runs on little-endian PPC64 code with VSX enabled. Loads and stores of 4x32 and 2x64 vectors without alignment constraints are accomplished for little-endian using lxvd2x/xxswapd and xxswapd/stxvd2x. The existence of the additional xxswapd instructions hurts performance in comparison with big-endian code, but they are necessary in the general case to support correct semantics. However, the general case does not apply to most vector code. Many vector instructions are lane-insensitive; they do not "care" which lanes the parallel computations are performed within, provided that the resulting data is stored into the correct locations. Thus this pass looks for computations that perform only lane-insensitive operations, and remove the unnecessary swaps from loads and stores in such computations. Future improvements will allow computations using certain lane-sensitive operations to also be optimized in this manner, by modifying the lane-sensitive operations to account for the permuted order of the lanes. However, this patch only adds the infrastructure to permit this; no lane-sensitive operations are optimized at this time. This code is heavily exercised by the various vectorizing applications in the projects/test-suite tree. For the time being, I have only added one simple test case to demonstrate what the pass is doing. Although it is quite simple, it provides coverage for much of the code, including the special case handling of copies and subreg-to-reg operations feeding the swaps. I plan to add additional tests in the future as I fill in more of the "special handling" code. Two existing tests were affected, because they expected the swaps to be present, but they are now removed. llvm-svn: 235910
2015-04-28 03:57:34 +08:00
}
}
if (SwapVector[EntryIdx].WebRejected)
DEBUG(dbgs() << "rejected ");
if (SwapVector[EntryIdx].WillRemove)
DEBUG(dbgs() << "remove ");
DEBUG(dbgs() << "\n");
Silence unused variable errors for no-asserts builds llvm-svn: 235913
2015-04-28 04:22:35 +08:00
// For no-asserts builds.
(void)MI;
(void)ID;
[PPC64LE] Remove unnecessary swaps from lane-insensitive vector computations This patch adds a new SSA MI pass that runs on little-endian PPC64 code with VSX enabled. Loads and stores of 4x32 and 2x64 vectors without alignment constraints are accomplished for little-endian using lxvd2x/xxswapd and xxswapd/stxvd2x. The existence of the additional xxswapd instructions hurts performance in comparison with big-endian code, but they are necessary in the general case to support correct semantics. However, the general case does not apply to most vector code. Many vector instructions are lane-insensitive; they do not "care" which lanes the parallel computations are performed within, provided that the resulting data is stored into the correct locations. Thus this pass looks for computations that perform only lane-insensitive operations, and remove the unnecessary swaps from loads and stores in such computations. Future improvements will allow computations using certain lane-sensitive operations to also be optimized in this manner, by modifying the lane-sensitive operations to account for the permuted order of the lanes. However, this patch only adds the infrastructure to permit this; no lane-sensitive operations are optimized at this time. This code is heavily exercised by the various vectorizing applications in the projects/test-suite tree. For the time being, I have only added one simple test case to demonstrate what the pass is doing. Although it is quite simple, it provides coverage for much of the code, including the special case handling of copies and subreg-to-reg operations feeding the swaps. I plan to add additional tests in the future as I fill in more of the "special handling" code. Two existing tests were affected, because they expected the swaps to be present, but they are now removed. llvm-svn: 235910
2015-04-28 03:57:34 +08:00
}
DEBUG(dbgs() << "\n");
}
Revert r240137 (Fixed/added namespace ending comments using clang-tidy. NFC) Apparently, the style needs to be agreed upon first. llvm-svn: 240390
2015-06-23 17:49:53 +08:00
} // end default namespace
[PPC64LE] Remove unnecessary swaps from lane-insensitive vector computations This patch adds a new SSA MI pass that runs on little-endian PPC64 code with VSX enabled. Loads and stores of 4x32 and 2x64 vectors without alignment constraints are accomplished for little-endian using lxvd2x/xxswapd and xxswapd/stxvd2x. The existence of the additional xxswapd instructions hurts performance in comparison with big-endian code, but they are necessary in the general case to support correct semantics. However, the general case does not apply to most vector code. Many vector instructions are lane-insensitive; they do not "care" which lanes the parallel computations are performed within, provided that the resulting data is stored into the correct locations. Thus this pass looks for computations that perform only lane-insensitive operations, and remove the unnecessary swaps from loads and stores in such computations. Future improvements will allow computations using certain lane-sensitive operations to also be optimized in this manner, by modifying the lane-sensitive operations to account for the permuted order of the lanes. However, this patch only adds the infrastructure to permit this; no lane-sensitive operations are optimized at this time. This code is heavily exercised by the various vectorizing applications in the projects/test-suite tree. For the time being, I have only added one simple test case to demonstrate what the pass is doing. Although it is quite simple, it provides coverage for much of the code, including the special case handling of copies and subreg-to-reg operations feeding the swaps. I plan to add additional tests in the future as I fill in more of the "special handling" code. Two existing tests were affected, because they expected the swaps to be present, but they are now removed. llvm-svn: 235910
2015-04-28 03:57:34 +08:00
INITIALIZE_PASS_BEGIN(PPCVSXSwapRemoval, DEBUG_TYPE,
"PowerPC VSX Swap Removal", false, false)
INITIALIZE_PASS_END(PPCVSXSwapRemoval, DEBUG_TYPE,
"PowerPC VSX Swap Removal", false, false)
char PPCVSXSwapRemoval::ID = 0;
FunctionPass*
llvm::createPPCVSXSwapRemovalPass() { return new PPCVSXSwapRemoval(); }