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llvm-project/llvm/lib/Target/SystemZ/SystemZISelDAGToDAG.cpp

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//===-- SystemZISelDAGToDAG.cpp - A dag to dag inst selector for SystemZ --===//
//
// The LLVM Compiler Infrastructure
//
// This file is distributed under the University of Illinois Open Source
// License. See LICENSE.TXT for details.
//
//===----------------------------------------------------------------------===//
//
// This file defines an instruction selector for the SystemZ target.
//
//===----------------------------------------------------------------------===//
#include "SystemZTargetMachine.h"
#include "llvm/Analysis/AliasAnalysis.h"
#include "llvm/CodeGen/SelectionDAGISel.h"
#include "llvm/Support/Debug.h"
#include "llvm/Support/raw_ostream.h"
using namespace llvm;
#define DEBUG_TYPE "systemz-isel"
namespace {
// Used to build addressing modes.
struct SystemZAddressingMode {
// The shape of the address.
enum AddrForm {
// base+displacement
FormBD,
// base+displacement+index for load and store operands
FormBDXNormal,
// base+displacement+index for load address operands
FormBDXLA,
// base+displacement+index+ADJDYNALLOC
FormBDXDynAlloc
};
AddrForm Form;
// The type of displacement. The enum names here correspond directly
// to the definitions in SystemZOperand.td. We could split them into
// flags -- single/pair, 128-bit, etc. -- but it hardly seems worth it.
enum DispRange {
Disp12Only,
Disp12Pair,
Disp20Only,
Disp20Only128,
Disp20Pair
};
DispRange DR;
// The parts of the address. The address is equivalent to:
//
// Base + Disp + Index + (IncludesDynAlloc ? ADJDYNALLOC : 0)
SDValue Base;
int64_t Disp;
SDValue Index;
bool IncludesDynAlloc;
SystemZAddressingMode(AddrForm form, DispRange dr)
: Form(form), DR(dr), Base(), Disp(0), Index(),
IncludesDynAlloc(false) {}
// True if the address can have an index register.
bool hasIndexField() { return Form != FormBD; }
// True if the address can (and must) include ADJDYNALLOC.
bool isDynAlloc() { return Form == FormBDXDynAlloc; }
void dump() {
errs() << "SystemZAddressingMode " << this << '\n';
errs() << " Base ";
if (Base.getNode())
Base.getNode()->dump();
else
errs() << "null\n";
if (hasIndexField()) {
errs() << " Index ";
if (Index.getNode())
Index.getNode()->dump();
else
errs() << "null\n";
}
errs() << " Disp " << Disp;
if (IncludesDynAlloc)
errs() << " + ADJDYNALLOC";
errs() << '\n';
}
};
// Return a mask with Count low bits set.
static uint64_t allOnes(unsigned int Count) {
return Count == 0 ? 0 : (uint64_t(1) << (Count - 1) << 1) - 1;
}
// Represents operands 2 to 5 of the ROTATE AND ... SELECTED BITS operation
// given by Opcode. The operands are: Input (R2), Start (I3), End (I4) and
// Rotate (I5). The combined operand value is effectively:
//
// (or (rotl Input, Rotate), ~Mask)
//
// for RNSBG and:
//
// (and (rotl Input, Rotate), Mask)
//
// otherwise. The output value has BitSize bits, although Input may be
// narrower (in which case the upper bits are don't care).
struct RxSBGOperands {
RxSBGOperands(unsigned Op, SDValue N)
: Opcode(Op), BitSize(N.getValueType().getSizeInBits()),
Mask(allOnes(BitSize)), Input(N), Start(64 - BitSize), End(63),
Rotate(0) {}
unsigned Opcode;
unsigned BitSize;
uint64_t Mask;
SDValue Input;
unsigned Start;
unsigned End;
unsigned Rotate;
};
class SystemZDAGToDAGISel : public SelectionDAGISel {
const SystemZSubtarget *Subtarget;
// Used by SystemZOperands.td to create integer constants.
inline SDValue getImm(const SDNode *Node, uint64_t Imm) const {
return CurDAG->getTargetConstant(Imm, Node->getValueType(0));
}
const SystemZTargetMachine &getTargetMachine() const {
return static_cast<const SystemZTargetMachine &>(TM);
}
const SystemZInstrInfo *getInstrInfo() const {
return Subtarget->getInstrInfo();
}
// Try to fold more of the base or index of AM into AM, where IsBase
// selects between the base and index.
bool expandAddress(SystemZAddressingMode &AM, bool IsBase) const;
// Try to describe N in AM, returning true on success.
bool selectAddress(SDValue N, SystemZAddressingMode &AM) const;
// Extract individual target operands from matched address AM.
void getAddressOperands(const SystemZAddressingMode &AM, EVT VT,
SDValue &Base, SDValue &Disp) const;
void getAddressOperands(const SystemZAddressingMode &AM, EVT VT,
SDValue &Base, SDValue &Disp, SDValue &Index) const;
// Try to match Addr as a FormBD address with displacement type DR.
// Return true on success, storing the base and displacement in
// Base and Disp respectively.
bool selectBDAddr(SystemZAddressingMode::DispRange DR, SDValue Addr,
SDValue &Base, SDValue &Disp) const;
// Try to match Addr as a FormBDX address with displacement type DR.
// Return true on success and if the result had no index. Store the
// base and displacement in Base and Disp respectively.
bool selectMVIAddr(SystemZAddressingMode::DispRange DR, SDValue Addr,
SDValue &Base, SDValue &Disp) const;
// Try to match Addr as a FormBDX* address of form Form with
// displacement type DR. Return true on success, storing the base,
// displacement and index in Base, Disp and Index respectively.
bool selectBDXAddr(SystemZAddressingMode::AddrForm Form,
SystemZAddressingMode::DispRange DR, SDValue Addr,
SDValue &Base, SDValue &Disp, SDValue &Index) const;
// PC-relative address matching routines used by SystemZOperands.td.
bool selectPCRelAddress(SDValue Addr, SDValue &Target) const {
if (SystemZISD::isPCREL(Addr.getOpcode())) {
Target = Addr.getOperand(0);
return true;
}
return false;
}
// BD matching routines used by SystemZOperands.td.
bool selectBDAddr12Only(SDValue Addr, SDValue &Base, SDValue &Disp) const {
return selectBDAddr(SystemZAddressingMode::Disp12Only, Addr, Base, Disp);
}
bool selectBDAddr12Pair(SDValue Addr, SDValue &Base, SDValue &Disp) const {
return selectBDAddr(SystemZAddressingMode::Disp12Pair, Addr, Base, Disp);
}
bool selectBDAddr20Only(SDValue Addr, SDValue &Base, SDValue &Disp) const {
return selectBDAddr(SystemZAddressingMode::Disp20Only, Addr, Base, Disp);
}
bool selectBDAddr20Pair(SDValue Addr, SDValue &Base, SDValue &Disp) const {
return selectBDAddr(SystemZAddressingMode::Disp20Pair, Addr, Base, Disp);
}
// MVI matching routines used by SystemZOperands.td.
bool selectMVIAddr12Pair(SDValue Addr, SDValue &Base, SDValue &Disp) const {
return selectMVIAddr(SystemZAddressingMode::Disp12Pair, Addr, Base, Disp);
}
bool selectMVIAddr20Pair(SDValue Addr, SDValue &Base, SDValue &Disp) const {
return selectMVIAddr(SystemZAddressingMode::Disp20Pair, Addr, Base, Disp);
}
// BDX matching routines used by SystemZOperands.td.
bool selectBDXAddr12Only(SDValue Addr, SDValue &Base, SDValue &Disp,
SDValue &Index) const {
return selectBDXAddr(SystemZAddressingMode::FormBDXNormal,
SystemZAddressingMode::Disp12Only,
Addr, Base, Disp, Index);
}
bool selectBDXAddr12Pair(SDValue Addr, SDValue &Base, SDValue &Disp,
SDValue &Index) const {
return selectBDXAddr(SystemZAddressingMode::FormBDXNormal,
SystemZAddressingMode::Disp12Pair,
Addr, Base, Disp, Index);
}
bool selectDynAlloc12Only(SDValue Addr, SDValue &Base, SDValue &Disp,
SDValue &Index) const {
return selectBDXAddr(SystemZAddressingMode::FormBDXDynAlloc,
SystemZAddressingMode::Disp12Only,
Addr, Base, Disp, Index);
}
bool selectBDXAddr20Only(SDValue Addr, SDValue &Base, SDValue &Disp,
SDValue &Index) const {
return selectBDXAddr(SystemZAddressingMode::FormBDXNormal,
SystemZAddressingMode::Disp20Only,
Addr, Base, Disp, Index);
}
bool selectBDXAddr20Only128(SDValue Addr, SDValue &Base, SDValue &Disp,
SDValue &Index) const {
return selectBDXAddr(SystemZAddressingMode::FormBDXNormal,
SystemZAddressingMode::Disp20Only128,
Addr, Base, Disp, Index);
}
bool selectBDXAddr20Pair(SDValue Addr, SDValue &Base, SDValue &Disp,
SDValue &Index) const {
return selectBDXAddr(SystemZAddressingMode::FormBDXNormal,
SystemZAddressingMode::Disp20Pair,
Addr, Base, Disp, Index);
}
bool selectLAAddr12Pair(SDValue Addr, SDValue &Base, SDValue &Disp,
SDValue &Index) const {
return selectBDXAddr(SystemZAddressingMode::FormBDXLA,
SystemZAddressingMode::Disp12Pair,
Addr, Base, Disp, Index);
}
bool selectLAAddr20Pair(SDValue Addr, SDValue &Base, SDValue &Disp,
SDValue &Index) const {
return selectBDXAddr(SystemZAddressingMode::FormBDXLA,
SystemZAddressingMode::Disp20Pair,
Addr, Base, Disp, Index);
}
// Check whether (or Op (and X InsertMask)) is effectively an insertion
// of X into bits InsertMask of some Y != Op. Return true if so and
// set Op to that Y.
bool detectOrAndInsertion(SDValue &Op, uint64_t InsertMask) const;
// Try to update RxSBG so that only the bits of RxSBG.Input in Mask are used.
// Return true on success.
bool refineRxSBGMask(RxSBGOperands &RxSBG, uint64_t Mask) const;
// Try to fold some of RxSBG.Input into other fields of RxSBG.
// Return true on success.
bool expandRxSBG(RxSBGOperands &RxSBG) const;
// Return an undefined value of type VT.
SDValue getUNDEF(SDLoc DL, EVT VT) const;
// Convert N to VT, if it isn't already.
SDValue convertTo(SDLoc DL, EVT VT, SDValue N) const;
// Try to implement AND or shift node N using RISBG with the zero flag set.
// Return the selected node on success, otherwise return null.
SDNode *tryRISBGZero(SDNode *N);
// Try to use RISBG or Opcode to implement OR or XOR node N.
// Return the selected node on success, otherwise return null.
SDNode *tryRxSBG(SDNode *N, unsigned Opcode);
// If Op0 is null, then Node is a constant that can be loaded using:
//
// (Opcode UpperVal LowerVal)
//
// If Op0 is nonnull, then Node can be implemented using:
//
// (Opcode (Opcode Op0 UpperVal) LowerVal)
SDNode *splitLargeImmediate(unsigned Opcode, SDNode *Node, SDValue Op0,
uint64_t UpperVal, uint64_t LowerVal);
// Return true if Load and Store are loads and stores of the same size
// and are guaranteed not to overlap. Such operations can be implemented
// using block (SS-format) instructions.
//
// Partial overlap would lead to incorrect code, since the block operations
// are logically bytewise, even though they have a fast path for the
// non-overlapping case. We also need to avoid full overlap (i.e. two
// addresses that might be equal at run time) because although that case
// would be handled correctly, it might be implemented by millicode.
bool canUseBlockOperation(StoreSDNode *Store, LoadSDNode *Load) const;
// N is a (store (load Y), X) pattern. Return true if it can use an MVC
// from Y to X.
bool storeLoadCanUseMVC(SDNode *N) const;
// N is a (store (op (load A[0]), (load A[1])), X) pattern. Return true
// if A[1 - I] == X and if N can use a block operation like NC from A[I]
// to X.
bool storeLoadCanUseBlockBinary(SDNode *N, unsigned I) const;
public:
SystemZDAGToDAGISel(SystemZTargetMachine &TM, CodeGenOpt::Level OptLevel)
: SelectionDAGISel(TM, OptLevel) {}
bool runOnMachineFunction(MachineFunction &MF) override {
Subtarget = &MF.getSubtarget<SystemZSubtarget>();
return SelectionDAGISel::runOnMachineFunction(MF);
}
// Override MachineFunctionPass.
const char *getPassName() const override {
return "SystemZ DAG->DAG Pattern Instruction Selection";
}
// Override SelectionDAGISel.
SDNode *Select(SDNode *Node) override;
bool SelectInlineAsmMemoryOperand(const SDValue &Op, unsigned ConstraintID,
std::vector<SDValue> &OutOps) override;
// Include the pieces autogenerated from the target description.
#include "SystemZGenDAGISel.inc"
};
} // end anonymous namespace
FunctionPass *llvm::createSystemZISelDag(SystemZTargetMachine &TM,
CodeGenOpt::Level OptLevel) {
return new SystemZDAGToDAGISel(TM, OptLevel);
}
// Return true if Val should be selected as a displacement for an address
// with range DR. Here we're interested in the range of both the instruction
// described by DR and of any pairing instruction.
static bool selectDisp(SystemZAddressingMode::DispRange DR, int64_t Val) {
switch (DR) {
case SystemZAddressingMode::Disp12Only:
return isUInt<12>(Val);
case SystemZAddressingMode::Disp12Pair:
case SystemZAddressingMode::Disp20Only:
case SystemZAddressingMode::Disp20Pair:
return isInt<20>(Val);
case SystemZAddressingMode::Disp20Only128:
return isInt<20>(Val) && isInt<20>(Val + 8);
}
llvm_unreachable("Unhandled displacement range");
}
// Change the base or index in AM to Value, where IsBase selects
// between the base and index.
static void changeComponent(SystemZAddressingMode &AM, bool IsBase,
SDValue Value) {
if (IsBase)
AM.Base = Value;
else
AM.Index = Value;
}
// The base or index of AM is equivalent to Value + ADJDYNALLOC,
// where IsBase selects between the base and index. Try to fold the
// ADJDYNALLOC into AM.
static bool expandAdjDynAlloc(SystemZAddressingMode &AM, bool IsBase,
SDValue Value) {
if (AM.isDynAlloc() && !AM.IncludesDynAlloc) {
changeComponent(AM, IsBase, Value);
AM.IncludesDynAlloc = true;
return true;
}
return false;
}
// The base of AM is equivalent to Base + Index. Try to use Index as
// the index register.
static bool expandIndex(SystemZAddressingMode &AM, SDValue Base,
SDValue Index) {
if (AM.hasIndexField() && !AM.Index.getNode()) {
AM.Base = Base;
AM.Index = Index;
return true;
}
return false;
}
// The base or index of AM is equivalent to Op0 + Op1, where IsBase selects
// between the base and index. Try to fold Op1 into AM's displacement.
static bool expandDisp(SystemZAddressingMode &AM, bool IsBase,
SDValue Op0, uint64_t Op1) {
// First try adjusting the displacement.
int64_t TestDisp = AM.Disp + Op1;
if (selectDisp(AM.DR, TestDisp)) {
changeComponent(AM, IsBase, Op0);
AM.Disp = TestDisp;
return true;
}
// We could consider forcing the displacement into a register and
// using it as an index, but it would need to be carefully tuned.
return false;
}
bool SystemZDAGToDAGISel::expandAddress(SystemZAddressingMode &AM,
bool IsBase) const {
SDValue N = IsBase ? AM.Base : AM.Index;
unsigned Opcode = N.getOpcode();
if (Opcode == ISD::TRUNCATE) {
N = N.getOperand(0);
Opcode = N.getOpcode();
}
if (Opcode == ISD::ADD || CurDAG->isBaseWithConstantOffset(N)) {
SDValue Op0 = N.getOperand(0);
SDValue Op1 = N.getOperand(1);
unsigned Op0Code = Op0->getOpcode();
unsigned Op1Code = Op1->getOpcode();
if (Op0Code == SystemZISD::ADJDYNALLOC)
return expandAdjDynAlloc(AM, IsBase, Op1);
if (Op1Code == SystemZISD::ADJDYNALLOC)
return expandAdjDynAlloc(AM, IsBase, Op0);
if (Op0Code == ISD::Constant)
return expandDisp(AM, IsBase, Op1,
cast<ConstantSDNode>(Op0)->getSExtValue());
if (Op1Code == ISD::Constant)
return expandDisp(AM, IsBase, Op0,
cast<ConstantSDNode>(Op1)->getSExtValue());
if (IsBase && expandIndex(AM, Op0, Op1))
return true;
}
if (Opcode == SystemZISD::PCREL_OFFSET) {
SDValue Full = N.getOperand(0);
SDValue Base = N.getOperand(1);
SDValue Anchor = Base.getOperand(0);
uint64_t Offset = (cast<GlobalAddressSDNode>(Full)->getOffset() -
cast<GlobalAddressSDNode>(Anchor)->getOffset());
return expandDisp(AM, IsBase, Base, Offset);
}
return false;
}
// Return true if an instruction with displacement range DR should be
// used for displacement value Val. selectDisp(DR, Val) must already hold.
static bool isValidDisp(SystemZAddressingMode::DispRange DR, int64_t Val) {
assert(selectDisp(DR, Val) && "Invalid displacement");
switch (DR) {
case SystemZAddressingMode::Disp12Only:
case SystemZAddressingMode::Disp20Only:
case SystemZAddressingMode::Disp20Only128:
return true;
case SystemZAddressingMode::Disp12Pair:
// Use the other instruction if the displacement is too large.
return isUInt<12>(Val);
case SystemZAddressingMode::Disp20Pair:
// Use the other instruction if the displacement is small enough.
return !isUInt<12>(Val);
}
llvm_unreachable("Unhandled displacement range");
}
// Return true if Base + Disp + Index should be performed by LA(Y).
static bool shouldUseLA(SDNode *Base, int64_t Disp, SDNode *Index) {
// Don't use LA(Y) for constants.
if (!Base)
return false;
// Always use LA(Y) for frame addresses, since we know that the destination
// register is almost always (perhaps always) going to be different from
// the frame register.
if (Base->getOpcode() == ISD::FrameIndex)
return true;
if (Disp) {
// Always use LA(Y) if there is a base, displacement and index.
if (Index)
return true;
// Always use LA if the displacement is small enough. It should always
// be no worse than AGHI (and better if it avoids a move).
if (isUInt<12>(Disp))
return true;
// For similar reasons, always use LAY if the constant is too big for AGHI.
// LAY should be no worse than AGFI.
if (!isInt<16>(Disp))
return true;
} else {
// Don't use LA for plain registers.
if (!Index)
return false;
// Don't use LA for plain addition if the index operand is only used
// once. It should be a natural two-operand addition in that case.
if (Index->hasOneUse())
return false;
// Prefer addition if the second operation is sign-extended, in the
// hope of using AGF.
unsigned IndexOpcode = Index->getOpcode();
if (IndexOpcode == ISD::SIGN_EXTEND ||
IndexOpcode == ISD::SIGN_EXTEND_INREG)
return false;
}
// Don't use LA for two-operand addition if either operand is only
// used once. The addition instructions are better in that case.
if (Base->hasOneUse())
return false;
return true;
}
// Return true if Addr is suitable for AM, updating AM if so.
bool SystemZDAGToDAGISel::selectAddress(SDValue Addr,
SystemZAddressingMode &AM) const {
// Start out assuming that the address will need to be loaded separately,
// then try to extend it as much as we can.
AM.Base = Addr;
// First try treating the address as a constant.
if (Addr.getOpcode() == ISD::Constant &&
expandDisp(AM, true, SDValue(),
cast<ConstantSDNode>(Addr)->getSExtValue()))
;
else
// Otherwise try expanding each component.
while (expandAddress(AM, true) ||
(AM.Index.getNode() && expandAddress(AM, false)))
continue;
// Reject cases where it isn't profitable to use LA(Y).
if (AM.Form == SystemZAddressingMode::FormBDXLA &&
!shouldUseLA(AM.Base.getNode(), AM.Disp, AM.Index.getNode()))
return false;
// Reject cases where the other instruction in a pair should be used.
if (!isValidDisp(AM.DR, AM.Disp))
return false;
// Make sure that ADJDYNALLOC is included where necessary.
if (AM.isDynAlloc() && !AM.IncludesDynAlloc)
return false;
DEBUG(AM.dump());
return true;
}
// Insert a node into the DAG at least before Pos. This will reposition
// the node as needed, and will assign it a node ID that is <= Pos's ID.
// Note that this does *not* preserve the uniqueness of node IDs!
// The selection DAG must no longer depend on their uniqueness when this
// function is used.
static void insertDAGNode(SelectionDAG *DAG, SDNode *Pos, SDValue N) {
if (N.getNode()->getNodeId() == -1 ||
N.getNode()->getNodeId() > Pos->getNodeId()) {
DAG->RepositionNode(Pos, N.getNode());
N.getNode()->setNodeId(Pos->getNodeId());
}
}
void SystemZDAGToDAGISel::getAddressOperands(const SystemZAddressingMode &AM,
EVT VT, SDValue &Base,
SDValue &Disp) const {
Base = AM.Base;
if (!Base.getNode())
// Register 0 means "no base". This is mostly useful for shifts.
Base = CurDAG->getRegister(0, VT);
else if (Base.getOpcode() == ISD::FrameIndex) {
// Lower a FrameIndex to a TargetFrameIndex.
int64_t FrameIndex = cast<FrameIndexSDNode>(Base)->getIndex();
Base = CurDAG->getTargetFrameIndex(FrameIndex, VT);
} else if (Base.getValueType() != VT) {
// Truncate values from i64 to i32, for shifts.
assert(VT == MVT::i32 && Base.getValueType() == MVT::i64 &&
"Unexpected truncation");
SDLoc DL(Base);
SDValue Trunc = CurDAG->getNode(ISD::TRUNCATE, DL, VT, Base);
insertDAGNode(CurDAG, Base.getNode(), Trunc);
Base = Trunc;
}
// Lower the displacement to a TargetConstant.
Disp = CurDAG->getTargetConstant(AM.Disp, VT);
}
void SystemZDAGToDAGISel::getAddressOperands(const SystemZAddressingMode &AM,
EVT VT, SDValue &Base,
SDValue &Disp,
SDValue &Index) const {
getAddressOperands(AM, VT, Base, Disp);
Index = AM.Index;
if (!Index.getNode())
// Register 0 means "no index".
Index = CurDAG->getRegister(0, VT);
}
bool SystemZDAGToDAGISel::selectBDAddr(SystemZAddressingMode::DispRange DR,
SDValue Addr, SDValue &Base,
SDValue &Disp) const {
SystemZAddressingMode AM(SystemZAddressingMode::FormBD, DR);
if (!selectAddress(Addr, AM))
return false;
getAddressOperands(AM, Addr.getValueType(), Base, Disp);
return true;
}
bool SystemZDAGToDAGISel::selectMVIAddr(SystemZAddressingMode::DispRange DR,
SDValue Addr, SDValue &Base,
SDValue &Disp) const {
SystemZAddressingMode AM(SystemZAddressingMode::FormBDXNormal, DR);
if (!selectAddress(Addr, AM) || AM.Index.getNode())
return false;
getAddressOperands(AM, Addr.getValueType(), Base, Disp);
return true;
}
bool SystemZDAGToDAGISel::selectBDXAddr(SystemZAddressingMode::AddrForm Form,
SystemZAddressingMode::DispRange DR,
SDValue Addr, SDValue &Base,
SDValue &Disp, SDValue &Index) const {
SystemZAddressingMode AM(Form, DR);
if (!selectAddress(Addr, AM))
return false;
getAddressOperands(AM, Addr.getValueType(), Base, Disp, Index);
return true;
}
bool SystemZDAGToDAGISel::detectOrAndInsertion(SDValue &Op,
uint64_t InsertMask) const {
// We're only interested in cases where the insertion is into some operand
// of Op, rather than into Op itself. The only useful case is an AND.
if (Op.getOpcode() != ISD::AND)
return false;
// We need a constant mask.
auto *MaskNode = dyn_cast<ConstantSDNode>(Op.getOperand(1).getNode());
if (!MaskNode)
return false;
// It's not an insertion of Op.getOperand(0) if the two masks overlap.
uint64_t AndMask = MaskNode->getZExtValue();
if (InsertMask & AndMask)
return false;
// It's only an insertion if all bits are covered or are known to be zero.
// The inner check covers all cases but is more expensive.
uint64_t Used = allOnes(Op.getValueType().getSizeInBits());
if (Used != (AndMask | InsertMask)) {
APInt KnownZero, KnownOne;
CurDAG->computeKnownBits(Op.getOperand(0), KnownZero, KnownOne);
if (Used != (AndMask | InsertMask | KnownZero.getZExtValue()))
return false;
}
Op = Op.getOperand(0);
return true;
}
bool SystemZDAGToDAGISel::refineRxSBGMask(RxSBGOperands &RxSBG,
uint64_t Mask) const {
const SystemZInstrInfo *TII = getInstrInfo();
if (RxSBG.Rotate != 0)
Mask = (Mask << RxSBG.Rotate) | (Mask >> (64 - RxSBG.Rotate));
Mask &= RxSBG.Mask;
if (TII->isRxSBGMask(Mask, RxSBG.BitSize, RxSBG.Start, RxSBG.End)) {
RxSBG.Mask = Mask;
return true;
}
return false;
}
// Return true if any bits of (RxSBG.Input & Mask) are significant.
static bool maskMatters(RxSBGOperands &RxSBG, uint64_t Mask) {
// Rotate the mask in the same way as RxSBG.Input is rotated.
if (RxSBG.Rotate != 0)
Mask = ((Mask << RxSBG.Rotate) | (Mask >> (64 - RxSBG.Rotate)));
return (Mask & RxSBG.Mask) != 0;
}
bool SystemZDAGToDAGISel::expandRxSBG(RxSBGOperands &RxSBG) const {
SDValue N = RxSBG.Input;
unsigned Opcode = N.getOpcode();
switch (Opcode) {
case ISD::AND: {
if (RxSBG.Opcode == SystemZ::RNSBG)
return false;
auto *MaskNode = dyn_cast<ConstantSDNode>(N.getOperand(1).getNode());
if (!MaskNode)
return false;
SDValue Input = N.getOperand(0);
uint64_t Mask = MaskNode->getZExtValue();
if (!refineRxSBGMask(RxSBG, Mask)) {
// If some bits of Input are already known zeros, those bits will have
// been removed from the mask. See if adding them back in makes the
// mask suitable.
APInt KnownZero, KnownOne;
CurDAG->computeKnownBits(Input, KnownZero, KnownOne);
Mask |= KnownZero.getZExtValue();
if (!refineRxSBGMask(RxSBG, Mask))
return false;
}
RxSBG.Input = Input;
return true;
}
case ISD::OR: {
if (RxSBG.Opcode != SystemZ::RNSBG)
return false;
auto *MaskNode = dyn_cast<ConstantSDNode>(N.getOperand(1).getNode());
if (!MaskNode)
return false;
SDValue Input = N.getOperand(0);
uint64_t Mask = ~MaskNode->getZExtValue();
if (!refineRxSBGMask(RxSBG, Mask)) {
// If some bits of Input are already known ones, those bits will have
// been removed from the mask. See if adding them back in makes the
// mask suitable.
APInt KnownZero, KnownOne;
CurDAG->computeKnownBits(Input, KnownZero, KnownOne);
Mask &= ~KnownOne.getZExtValue();
if (!refineRxSBGMask(RxSBG, Mask))
return false;
}
RxSBG.Input = Input;
return true;
}
case ISD::ROTL: {
// Any 64-bit rotate left can be merged into the RxSBG.
if (RxSBG.BitSize != 64 || N.getValueType() != MVT::i64)
return false;
auto *CountNode = dyn_cast<ConstantSDNode>(N.getOperand(1).getNode());
if (!CountNode)
return false;
RxSBG.Rotate = (RxSBG.Rotate + CountNode->getZExtValue()) & 63;
RxSBG.Input = N.getOperand(0);
return true;
}
case ISD::ANY_EXTEND:
// Bits above the extended operand are don't-care.
RxSBG.Input = N.getOperand(0);
return true;
case ISD::ZERO_EXTEND:
if (RxSBG.Opcode != SystemZ::RNSBG) {
// Restrict the mask to the extended operand.
unsigned InnerBitSize = N.getOperand(0).getValueType().getSizeInBits();
if (!refineRxSBGMask(RxSBG, allOnes(InnerBitSize)))
return false;
RxSBG.Input = N.getOperand(0);
return true;
}
// Fall through.
case ISD::SIGN_EXTEND: {
// Check that the extension bits are don't-care (i.e. are masked out
// by the final mask).
unsigned InnerBitSize = N.getOperand(0).getValueType().getSizeInBits();
if (maskMatters(RxSBG, allOnes(RxSBG.BitSize) - allOnes(InnerBitSize)))
return false;
RxSBG.Input = N.getOperand(0);
return true;
}
case ISD::SHL: {
auto *CountNode = dyn_cast<ConstantSDNode>(N.getOperand(1).getNode());
if (!CountNode)
return false;
uint64_t Count = CountNode->getZExtValue();
unsigned BitSize = N.getValueType().getSizeInBits();
if (Count < 1 || Count >= BitSize)
return false;
if (RxSBG.Opcode == SystemZ::RNSBG) {
// Treat (shl X, count) as (rotl X, size-count) as long as the bottom
// count bits from RxSBG.Input are ignored.
if (maskMatters(RxSBG, allOnes(Count)))
return false;
} else {
// Treat (shl X, count) as (and (rotl X, count), ~0<<count).
if (!refineRxSBGMask(RxSBG, allOnes(BitSize - Count) << Count))
return false;
}
RxSBG.Rotate = (RxSBG.Rotate + Count) & 63;
RxSBG.Input = N.getOperand(0);
return true;
}
case ISD::SRL:
case ISD::SRA: {
auto *CountNode = dyn_cast<ConstantSDNode>(N.getOperand(1).getNode());
if (!CountNode)
return false;
uint64_t Count = CountNode->getZExtValue();
unsigned BitSize = N.getValueType().getSizeInBits();
if (Count < 1 || Count >= BitSize)
return false;
if (RxSBG.Opcode == SystemZ::RNSBG || Opcode == ISD::SRA) {
// Treat (srl|sra X, count) as (rotl X, size-count) as long as the top
// count bits from RxSBG.Input are ignored.
if (maskMatters(RxSBG, allOnes(Count) << (BitSize - Count)))
return false;
} else {
// Treat (srl X, count), mask) as (and (rotl X, size-count), ~0>>count),
// which is similar to SLL above.
if (!refineRxSBGMask(RxSBG, allOnes(BitSize - Count)))
return false;
}
RxSBG.Rotate = (RxSBG.Rotate - Count) & 63;
RxSBG.Input = N.getOperand(0);
return true;
}
default:
return false;
}
}
SDValue SystemZDAGToDAGISel::getUNDEF(SDLoc DL, EVT VT) const {
SDNode *N = CurDAG->getMachineNode(TargetOpcode::IMPLICIT_DEF, DL, VT);
return SDValue(N, 0);
}
SDValue SystemZDAGToDAGISel::convertTo(SDLoc DL, EVT VT, SDValue N) const {
if (N.getValueType() == MVT::i32 && VT == MVT::i64)
return CurDAG->getTargetInsertSubreg(SystemZ::subreg_l32,
DL, VT, getUNDEF(DL, MVT::i64), N);
if (N.getValueType() == MVT::i64 && VT == MVT::i32)
return CurDAG->getTargetExtractSubreg(SystemZ::subreg_l32, DL, VT, N);
assert(N.getValueType() == VT && "Unexpected value types");
return N;
}
SDNode *SystemZDAGToDAGISel::tryRISBGZero(SDNode *N) {
EVT VT = N->getValueType(0);
RxSBGOperands RISBG(SystemZ::RISBG, SDValue(N, 0));
unsigned Count = 0;
while (expandRxSBG(RISBG))
if (RISBG.Input.getOpcode() != ISD::ANY_EXTEND)
Count += 1;
if (Count == 0)
return nullptr;
if (Count == 1) {
// Prefer to use normal shift instructions over RISBG, since they can handle
// all cases and are sometimes shorter.
if (N->getOpcode() != ISD::AND)
return nullptr;
// Prefer register extensions like LLC over RISBG. Also prefer to start
// out with normal ANDs if one instruction would be enough. We can convert
// these ANDs into an RISBG later if a three-address instruction is useful.
if (VT == MVT::i32 ||
RISBG.Mask == 0xff ||
RISBG.Mask == 0xffff ||
SystemZ::isImmLF(~RISBG.Mask) ||
SystemZ::isImmHF(~RISBG.Mask)) {
// Force the new mask into the DAG, since it may include known-one bits.
auto *MaskN = cast<ConstantSDNode>(N->getOperand(1).getNode());
if (MaskN->getZExtValue() != RISBG.Mask) {
SDValue NewMask = CurDAG->getConstant(RISBG.Mask, VT);
N = CurDAG->UpdateNodeOperands(N, N->getOperand(0), NewMask);
return SelectCode(N);
}
return nullptr;
}
}
unsigned Opcode = SystemZ::RISBG;
// Prefer RISBGN if available, since it does not clobber CC.
if (Subtarget->hasMiscellaneousExtensions())
Opcode = SystemZ::RISBGN;
EVT OpcodeVT = MVT::i64;
if (VT == MVT::i32 && Subtarget->hasHighWord()) {
Opcode = SystemZ::RISBMux;
OpcodeVT = MVT::i32;
RISBG.Start &= 31;
RISBG.End &= 31;
}
SDValue Ops[5] = {
getUNDEF(SDLoc(N), OpcodeVT),
convertTo(SDLoc(N), OpcodeVT, RISBG.Input),
CurDAG->getTargetConstant(RISBG.Start, MVT::i32),
CurDAG->getTargetConstant(RISBG.End | 128, MVT::i32),
CurDAG->getTargetConstant(RISBG.Rotate, MVT::i32)
};
N = CurDAG->getMachineNode(Opcode, SDLoc(N), OpcodeVT, Ops);
return convertTo(SDLoc(N), VT, SDValue(N, 0)).getNode();
}
SDNode *SystemZDAGToDAGISel::tryRxSBG(SDNode *N, unsigned Opcode) {
// Try treating each operand of N as the second operand of the RxSBG
// and see which goes deepest.
RxSBGOperands RxSBG[] = {
RxSBGOperands(Opcode, N->getOperand(0)),
RxSBGOperands(Opcode, N->getOperand(1))
};
unsigned Count[] = { 0, 0 };
for (unsigned I = 0; I < 2; ++I)
while (expandRxSBG(RxSBG[I]))
if (RxSBG[I].Input.getOpcode() != ISD::ANY_EXTEND)
Count[I] += 1;
// Do nothing if neither operand is suitable.
if (Count[0] == 0 && Count[1] == 0)
return nullptr;
// Pick the deepest second operand.
unsigned I = Count[0] > Count[1] ? 0 : 1;
SDValue Op0 = N->getOperand(I ^ 1);
// Prefer IC for character insertions from memory.
if (Opcode == SystemZ::ROSBG && (RxSBG[I].Mask & 0xff) == 0)
if (auto *Load = dyn_cast<LoadSDNode>(Op0.getNode()))
if (Load->getMemoryVT() == MVT::i8)
return nullptr;
// See whether we can avoid an AND in the first operand by converting
// ROSBG to RISBG.
if (Opcode == SystemZ::ROSBG && detectOrAndInsertion(Op0, RxSBG[I].Mask)) {
Opcode = SystemZ::RISBG;
// Prefer RISBGN if available, since it does not clobber CC.
if (Subtarget->hasMiscellaneousExtensions())
Opcode = SystemZ::RISBGN;
}
EVT VT = N->getValueType(0);
SDValue Ops[5] = {
convertTo(SDLoc(N), MVT::i64, Op0),
convertTo(SDLoc(N), MVT::i64, RxSBG[I].Input),
CurDAG->getTargetConstant(RxSBG[I].Start, MVT::i32),
CurDAG->getTargetConstant(RxSBG[I].End, MVT::i32),
CurDAG->getTargetConstant(RxSBG[I].Rotate, MVT::i32)
};
N = CurDAG->getMachineNode(Opcode, SDLoc(N), MVT::i64, Ops);
return convertTo(SDLoc(N), VT, SDValue(N, 0)).getNode();
}
SDNode *SystemZDAGToDAGISel::splitLargeImmediate(unsigned Opcode, SDNode *Node,
SDValue Op0, uint64_t UpperVal,
uint64_t LowerVal) {
EVT VT = Node->getValueType(0);
SDLoc DL(Node);
SDValue Upper = CurDAG->getConstant(UpperVal, VT);
if (Op0.getNode())
Upper = CurDAG->getNode(Opcode, DL, VT, Op0, Upper);
Upper = SDValue(Select(Upper.getNode()), 0);
SDValue Lower = CurDAG->getConstant(LowerVal, VT);
SDValue Or = CurDAG->getNode(Opcode, DL, VT, Upper, Lower);
return Or.getNode();
}
bool SystemZDAGToDAGISel::canUseBlockOperation(StoreSDNode *Store,
LoadSDNode *Load) const {
// Check that the two memory operands have the same size.
if (Load->getMemoryVT() != Store->getMemoryVT())
return false;
// Volatility stops an access from being decomposed.
if (Load->isVolatile() || Store->isVolatile())
return false;
// There's no chance of overlap if the load is invariant.
if (Load->isInvariant())
return true;
// Otherwise we need to check whether there's an alias.
const Value *V1 = Load->getMemOperand()->getValue();
const Value *V2 = Store->getMemOperand()->getValue();
if (!V1 || !V2)
return false;
// Reject equality.
uint64_t Size = Load->getMemoryVT().getStoreSize();
int64_t End1 = Load->getSrcValueOffset() + Size;
int64_t End2 = Store->getSrcValueOffset() + Size;
if (V1 == V2 && End1 == End2)
return false;
return !AA->alias(AliasAnalysis::Location(V1, End1, Load->getAAInfo()),
AliasAnalysis::Location(V2, End2, Store->getAAInfo()));
}
bool SystemZDAGToDAGISel::storeLoadCanUseMVC(SDNode *N) const {
auto *Store = cast<StoreSDNode>(N);
auto *Load = cast<LoadSDNode>(Store->getValue());
// Prefer not to use MVC if either address can use ... RELATIVE LONG
// instructions.
uint64_t Size = Load->getMemoryVT().getStoreSize();
if (Size > 1 && Size <= 8) {
// Prefer LHRL, LRL and LGRL.
if (SystemZISD::isPCREL(Load->getBasePtr().getOpcode()))
return false;
// Prefer STHRL, STRL and STGRL.
if (SystemZISD::isPCREL(Store->getBasePtr().getOpcode()))
return false;
}
return canUseBlockOperation(Store, Load);
}
bool SystemZDAGToDAGISel::storeLoadCanUseBlockBinary(SDNode *N,
unsigned I) const {
auto *StoreA = cast<StoreSDNode>(N);
auto *LoadA = cast<LoadSDNode>(StoreA->getValue().getOperand(1 - I));
auto *LoadB = cast<LoadSDNode>(StoreA->getValue().getOperand(I));
return !LoadA->isVolatile() && canUseBlockOperation(StoreA, LoadB);
}
SDNode *SystemZDAGToDAGISel::Select(SDNode *Node) {
// Dump information about the Node being selected
DEBUG(errs() << "Selecting: "; Node->dump(CurDAG); errs() << "\n");
// If we have a custom node, we already have selected!
if (Node->isMachineOpcode()) {
DEBUG(errs() << "== "; Node->dump(CurDAG); errs() << "\n");
Node->setNodeId(-1);
return nullptr;
}
unsigned Opcode = Node->getOpcode();
SDNode *ResNode = nullptr;
switch (Opcode) {
case ISD::OR:
if (Node->getOperand(1).getOpcode() != ISD::Constant)
ResNode = tryRxSBG(Node, SystemZ::ROSBG);
goto or_xor;
case ISD::XOR:
if (Node->getOperand(1).getOpcode() != ISD::Constant)
ResNode = tryRxSBG(Node, SystemZ::RXSBG);
// Fall through.
or_xor:
// If this is a 64-bit operation in which both 32-bit halves are nonzero,
// split the operation into two.
if (!ResNode && Node->getValueType(0) == MVT::i64)
if (auto *Op1 = dyn_cast<ConstantSDNode>(Node->getOperand(1))) {
uint64_t Val = Op1->getZExtValue();
if (!SystemZ::isImmLF(Val) && !SystemZ::isImmHF(Val))
Node = splitLargeImmediate(Opcode, Node, Node->getOperand(0),
Val - uint32_t(Val), uint32_t(Val));
}
break;
case ISD::AND:
if (Node->getOperand(1).getOpcode() != ISD::Constant)
ResNode = tryRxSBG(Node, SystemZ::RNSBG);
// Fall through.
case ISD::ROTL:
case ISD::SHL:
case ISD::SRL:
case ISD::ZERO_EXTEND:
if (!ResNode)
ResNode = tryRISBGZero(Node);
break;
case ISD::Constant:
// If this is a 64-bit constant that is out of the range of LLILF,
// LLIHF and LGFI, split it into two 32-bit pieces.
if (Node->getValueType(0) == MVT::i64) {
uint64_t Val = cast<ConstantSDNode>(Node)->getZExtValue();
if (!SystemZ::isImmLF(Val) && !SystemZ::isImmHF(Val) && !isInt<32>(Val))
Node = splitLargeImmediate(ISD::OR, Node, SDValue(),
Val - uint32_t(Val), uint32_t(Val));
}
break;
case SystemZISD::SELECT_CCMASK: {
SDValue Op0 = Node->getOperand(0);
SDValue Op1 = Node->getOperand(1);
// Prefer to put any load first, so that it can be matched as a
// conditional load.
if (Op1.getOpcode() == ISD::LOAD && Op0.getOpcode() != ISD::LOAD) {
SDValue CCValid = Node->getOperand(2);
SDValue CCMask = Node->getOperand(3);
uint64_t ConstCCValid =
cast<ConstantSDNode>(CCValid.getNode())->getZExtValue();
uint64_t ConstCCMask =
cast<ConstantSDNode>(CCMask.getNode())->getZExtValue();
// Invert the condition.
CCMask = CurDAG->getConstant(ConstCCValid ^ ConstCCMask,
CCMask.getValueType());
SDValue Op4 = Node->getOperand(4);
Node = CurDAG->UpdateNodeOperands(Node, Op1, Op0, CCValid, CCMask, Op4);
}
break;
}
}
// Select the default instruction
if (!ResNode)
ResNode = SelectCode(Node);
DEBUG(errs() << "=> ";
if (ResNode == nullptr || ResNode == Node)
Node->dump(CurDAG);
else
ResNode->dump(CurDAG);
errs() << "\n";
);
return ResNode;
}
bool SystemZDAGToDAGISel::
SelectInlineAsmMemoryOperand(const SDValue &Op,
unsigned ConstraintID,
std::vector<SDValue> &OutOps) {
switch(ConstraintID) {
default:
llvm_unreachable("Unexpected asm memory constraint");
case InlineAsm::Constraint_i:
case InlineAsm::Constraint_m:
case InlineAsm::Constraint_Q:
case InlineAsm::Constraint_R:
case InlineAsm::Constraint_S:
case InlineAsm::Constraint_T:
// Accept addresses with short displacements, which are compatible
// with Q, R, S and T. But keep the index operand for future expansion.
SDValue Base, Disp, Index;
if (selectBDXAddr(SystemZAddressingMode::FormBD,
SystemZAddressingMode::Disp12Only,
Op, Base, Disp, Index)) {
OutOps.push_back(Base);
OutOps.push_back(Disp);
OutOps.push_back(Index);
return false;
}
break;
}
return true;
}
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