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llvm-project/llvm/lib/Target/Hexagon/HexagonISelDAGToDAG.cpp

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//===-- HexagonISelDAGToDAG.cpp - A dag to dag inst selector for Hexagon --===//
//
// 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 Hexagon target.
//
//===----------------------------------------------------------------------===//
#include "Hexagon.h"
#include "HexagonISelDAGToDAG.h"
#include "HexagonISelLowering.h"
#include "HexagonMachineFunctionInfo.h"
#include "HexagonTargetMachine.h"
#include "llvm/CodeGen/FunctionLoweringInfo.h"
#include "llvm/CodeGen/MachineInstrBuilder.h"
#include "llvm/CodeGen/SelectionDAGISel.h"
#include "llvm/IR/Intrinsics.h"
#include "llvm/Support/CommandLine.h"
#include "llvm/Support/Debug.h"
using namespace llvm;
#define DEBUG_TYPE "hexagon-isel"
static
cl::opt<bool>
EnableAddressRebalancing("isel-rebalance-addr", cl::Hidden, cl::init(true),
cl::desc("Rebalance address calculation trees to improve "
"instruction selection"));
// Rebalance only if this allows e.g. combining a GA with an offset or
// factoring out a shift.
static
cl::opt<bool>
RebalanceOnlyForOptimizations("rebalance-only-opt", cl::Hidden, cl::init(false),
cl::desc("Rebalance address tree only if this allows optimizations"));
static
cl::opt<bool>
RebalanceOnlyImbalancedTrees("rebalance-only-imbal", cl::Hidden,
cl::init(false), cl::desc("Rebalance address tree only if it is imbalanced"));
static cl::opt<bool> CheckSingleUse("hexagon-isel-su", cl::Hidden,
cl::init(true), cl::desc("Enable checking of SDNode's single-use status"));
//===----------------------------------------------------------------------===//
// Instruction Selector Implementation
//===----------------------------------------------------------------------===//
#define GET_DAGISEL_BODY HexagonDAGToDAGISel
#include "HexagonGenDAGISel.inc"
/// createHexagonISelDag - This pass converts a legalized DAG into a
/// Hexagon-specific DAG, ready for instruction scheduling.
///
namespace llvm {
FunctionPass *createHexagonISelDag(HexagonTargetMachine &TM,
CodeGenOpt::Level OptLevel) {
return new HexagonDAGToDAGISel(TM, OptLevel);
}
}
// Intrinsics that return a a predicate.
static bool doesIntrinsicReturnPredicate(unsigned ID) {
switch (ID) {
default:
return false;
case Intrinsic::hexagon_C2_cmpeq:
case Intrinsic::hexagon_C2_cmpgt:
case Intrinsic::hexagon_C2_cmpgtu:
case Intrinsic::hexagon_C2_cmpgtup:
case Intrinsic::hexagon_C2_cmpgtp:
case Intrinsic::hexagon_C2_cmpeqp:
case Intrinsic::hexagon_C2_bitsset:
case Intrinsic::hexagon_C2_bitsclr:
case Intrinsic::hexagon_C2_cmpeqi:
case Intrinsic::hexagon_C2_cmpgti:
case Intrinsic::hexagon_C2_cmpgtui:
case Intrinsic::hexagon_C2_cmpgei:
case Intrinsic::hexagon_C2_cmpgeui:
case Intrinsic::hexagon_C2_cmplt:
case Intrinsic::hexagon_C2_cmpltu:
case Intrinsic::hexagon_C2_bitsclri:
case Intrinsic::hexagon_C2_and:
case Intrinsic::hexagon_C2_or:
case Intrinsic::hexagon_C2_xor:
case Intrinsic::hexagon_C2_andn:
case Intrinsic::hexagon_C2_not:
case Intrinsic::hexagon_C2_orn:
case Intrinsic::hexagon_C2_pxfer_map:
case Intrinsic::hexagon_C2_any8:
case Intrinsic::hexagon_C2_all8:
case Intrinsic::hexagon_A2_vcmpbeq:
case Intrinsic::hexagon_A2_vcmpbgtu:
case Intrinsic::hexagon_A2_vcmpheq:
case Intrinsic::hexagon_A2_vcmphgt:
case Intrinsic::hexagon_A2_vcmphgtu:
case Intrinsic::hexagon_A2_vcmpweq:
case Intrinsic::hexagon_A2_vcmpwgt:
case Intrinsic::hexagon_A2_vcmpwgtu:
case Intrinsic::hexagon_C2_tfrrp:
case Intrinsic::hexagon_S2_tstbit_i:
case Intrinsic::hexagon_S2_tstbit_r:
return true;
}
}
void HexagonDAGToDAGISel::SelectIndexedLoad(LoadSDNode *LD, const SDLoc &dl) {
SDValue Chain = LD->getChain();
SDValue Base = LD->getBasePtr();
SDValue Offset = LD->getOffset();
int32_t Inc = cast<ConstantSDNode>(Offset.getNode())->getSExtValue();
EVT LoadedVT = LD->getMemoryVT();
unsigned Opcode = 0;
// Check for zero extended loads. Treat any-extend loads as zero extended
// loads.
ISD::LoadExtType ExtType = LD->getExtensionType();
bool IsZeroExt = (ExtType == ISD::ZEXTLOAD || ExtType == ISD::EXTLOAD);
bool IsValidInc = HII->isValidAutoIncImm(LoadedVT, Inc);
assert(LoadedVT.isSimple());
switch (LoadedVT.getSimpleVT().SimpleTy) {
case MVT::i8:
if (IsZeroExt)
Opcode = IsValidInc ? Hexagon::L2_loadrub_pi : Hexagon::L2_loadrub_io;
else
Opcode = IsValidInc ? Hexagon::L2_loadrb_pi : Hexagon::L2_loadrb_io;
break;
case MVT::i16:
if (IsZeroExt)
Opcode = IsValidInc ? Hexagon::L2_loadruh_pi : Hexagon::L2_loadruh_io;
else
Opcode = IsValidInc ? Hexagon::L2_loadrh_pi : Hexagon::L2_loadrh_io;
break;
case MVT::i32:
Opcode = IsValidInc ? Hexagon::L2_loadri_pi : Hexagon::L2_loadri_io;
break;
case MVT::i64:
Opcode = IsValidInc ? Hexagon::L2_loadrd_pi : Hexagon::L2_loadrd_io;
break;
// 64B
case MVT::v64i8:
case MVT::v32i16:
case MVT::v16i32:
case MVT::v8i64:
case MVT::v128i8:
case MVT::v64i16:
case MVT::v32i32:
case MVT::v16i64:
if (isAlignedMemNode(LD)) {
if (LD->isNonTemporal())
Opcode = IsValidInc ? Hexagon::V6_vL32b_nt_pi : Hexagon::V6_vL32b_nt_ai;
else
Opcode = IsValidInc ? Hexagon::V6_vL32b_pi : Hexagon::V6_vL32b_ai;
} else {
Opcode = IsValidInc ? Hexagon::V6_vL32Ub_pi : Hexagon::V6_vL32Ub_ai;
}
break;
default:
llvm_unreachable("Unexpected memory type in indexed load");
}
SDValue IncV = CurDAG->getTargetConstant(Inc, dl, MVT::i32);
MachineSDNode::mmo_iterator MemOp = MF->allocateMemRefsArray(1);
MemOp[0] = LD->getMemOperand();
auto getExt64 = [this,ExtType] (MachineSDNode *N, const SDLoc &dl)
-> MachineSDNode* {
if (ExtType == ISD::ZEXTLOAD || ExtType == ISD::EXTLOAD) {
SDValue Zero = CurDAG->getTargetConstant(0, dl, MVT::i32);
return CurDAG->getMachineNode(Hexagon::A4_combineir, dl, MVT::i64,
Zero, SDValue(N, 0));
}
if (ExtType == ISD::SEXTLOAD)
return CurDAG->getMachineNode(Hexagon::A2_sxtw, dl, MVT::i64,
SDValue(N, 0));
return N;
};
// Loaded value Next address Chain
SDValue From[3] = { SDValue(LD,0), SDValue(LD,1), SDValue(LD,2) };
SDValue To[3];
EVT ValueVT = LD->getValueType(0);
if (ValueVT == MVT::i64 && ExtType != ISD::NON_EXTLOAD) {
// A load extending to i64 will actually produce i32, which will then
// need to be extended to i64.
assert(LoadedVT.getSizeInBits() <= 32);
ValueVT = MVT::i32;
}
if (IsValidInc) {
MachineSDNode *L = CurDAG->getMachineNode(Opcode, dl, ValueVT,
MVT::i32, MVT::Other, Base,
IncV, Chain);
L->setMemRefs(MemOp, MemOp+1);
To[1] = SDValue(L, 1); // Next address.
To[2] = SDValue(L, 2); // Chain.
// Handle special case for extension to i64.
if (LD->getValueType(0) == MVT::i64)
L = getExt64(L, dl);
To[0] = SDValue(L, 0); // Loaded (extended) value.
} else {
SDValue Zero = CurDAG->getTargetConstant(0, dl, MVT::i32);
MachineSDNode *L = CurDAG->getMachineNode(Opcode, dl, ValueVT, MVT::Other,
Base, Zero, Chain);
L->setMemRefs(MemOp, MemOp+1);
To[2] = SDValue(L, 1); // Chain.
MachineSDNode *A = CurDAG->getMachineNode(Hexagon::A2_addi, dl, MVT::i32,
Base, IncV);
To[1] = SDValue(A, 0); // Next address.
// Handle special case for extension to i64.
if (LD->getValueType(0) == MVT::i64)
L = getExt64(L, dl);
To[0] = SDValue(L, 0); // Loaded (extended) value.
}
ReplaceUses(From, To, 3);
CurDAG->RemoveDeadNode(LD);
}
MachineSDNode *HexagonDAGToDAGISel::LoadInstrForLoadIntrinsic(SDNode *IntN) {
if (IntN->getOpcode() != ISD::INTRINSIC_W_CHAIN)
return nullptr;
SDLoc dl(IntN);
unsigned IntNo = cast<ConstantSDNode>(IntN->getOperand(1))->getZExtValue();
static std::map<unsigned,unsigned> LoadPciMap = {
{ Intrinsic::hexagon_circ_ldb, Hexagon::L2_loadrb_pci },
{ Intrinsic::hexagon_circ_ldub, Hexagon::L2_loadrub_pci },
{ Intrinsic::hexagon_circ_ldh, Hexagon::L2_loadrh_pci },
{ Intrinsic::hexagon_circ_lduh, Hexagon::L2_loadruh_pci },
{ Intrinsic::hexagon_circ_ldw, Hexagon::L2_loadri_pci },
{ Intrinsic::hexagon_circ_ldd, Hexagon::L2_loadrd_pci },
};
auto FLC = LoadPciMap.find(IntNo);
if (FLC != LoadPciMap.end()) {
SDNode *Mod = CurDAG->getMachineNode(Hexagon::A2_tfrrcr, dl, MVT::i32,
IntN->getOperand(4));
EVT ValTy = (IntNo == Intrinsic::hexagon_circ_ldd) ? MVT::i64 : MVT::i32;
EVT RTys[] = { ValTy, MVT::i32, MVT::Other };
// Operands: { Base, Increment, Modifier, Chain }
auto Inc = cast<ConstantSDNode>(IntN->getOperand(5));
SDValue I = CurDAG->getTargetConstant(Inc->getSExtValue(), dl, MVT::i32);
MachineSDNode *Res = CurDAG->getMachineNode(FLC->second, dl, RTys,
{ IntN->getOperand(2), I, SDValue(Mod,0), IntN->getOperand(0) });
return Res;
}
static std::map<unsigned,unsigned> LoadPbrMap = {
{ Intrinsic::hexagon_brev_ldb, Hexagon::L2_loadrb_pbr },
{ Intrinsic::hexagon_brev_ldub, Hexagon::L2_loadrub_pbr },
{ Intrinsic::hexagon_brev_ldh, Hexagon::L2_loadrh_pbr },
{ Intrinsic::hexagon_brev_lduh, Hexagon::L2_loadruh_pbr },
{ Intrinsic::hexagon_brev_ldw, Hexagon::L2_loadri_pbr },
{ Intrinsic::hexagon_brev_ldd, Hexagon::L2_loadrd_pbr },
};
auto FLB = LoadPbrMap.find(IntNo);
if (FLB != LoadPbrMap.end()) {
SDNode *Mod = CurDAG->getMachineNode(Hexagon::A2_tfrrcr, dl, MVT::i32,
IntN->getOperand(4));
EVT ValTy = (IntNo == Intrinsic::hexagon_brev_ldd) ? MVT::i64 : MVT::i32;
EVT RTys[] = { ValTy, MVT::i32, MVT::Other };
// Operands: { Base, Modifier, Chain }
MachineSDNode *Res = CurDAG->getMachineNode(FLB->second, dl, RTys,
{ IntN->getOperand(2), SDValue(Mod,0), IntN->getOperand(0) });
return Res;
}
return nullptr;
}
SDNode *HexagonDAGToDAGISel::StoreInstrForLoadIntrinsic(MachineSDNode *LoadN,
SDNode *IntN) {
// The "LoadN" is just a machine load instruction. The intrinsic also
// involves storing it. Generate an appropriate store to the location
// given in the intrinsic's operand(3).
uint64_t F = HII->get(LoadN->getMachineOpcode()).TSFlags;
unsigned SizeBits = (F >> HexagonII::MemAccessSizePos) &
HexagonII::MemAccesSizeMask;
unsigned Size = 1U << (SizeBits-1);
SDLoc dl(IntN);
MachinePointerInfo PI;
SDValue TS;
SDValue Loc = IntN->getOperand(3);
if (Size >= 4)
TS = CurDAG->getStore(SDValue(LoadN, 2), dl, SDValue(LoadN, 0), Loc, PI,
Size);
else
TS = CurDAG->getTruncStore(SDValue(LoadN, 2), dl, SDValue(LoadN, 0), Loc,
PI, MVT::getIntegerVT(Size * 8), Size);
SDNode *StoreN;
{
HandleSDNode Handle(TS);
SelectStore(TS.getNode());
StoreN = Handle.getValue().getNode();
}
// Load's results are { Loaded value, Updated pointer, Chain }
ReplaceUses(SDValue(IntN, 0), SDValue(LoadN, 1));
ReplaceUses(SDValue(IntN, 1), SDValue(StoreN, 0));
return StoreN;
}
bool HexagonDAGToDAGISel::tryLoadOfLoadIntrinsic(LoadSDNode *N) {
// The intrinsics for load circ/brev perform two operations:
// 1. Load a value V from the specified location, using the addressing
// mode corresponding to the intrinsic.
// 2. Store V into a specified location. This location is typically a
// local, temporary object.
// In many cases, the program using these intrinsics will immediately
// load V again from the local object. In those cases, when certain
// conditions are met, the last load can be removed.
// This function identifies and optimizes this pattern. If the pattern
// cannot be optimized, it returns nullptr, which will cause the load
// to be selected separately from the intrinsic (which will be handled
// in SelectIntrinsicWChain).
SDValue Ch = N->getOperand(0);
SDValue Loc = N->getOperand(1);
// Assume that the load and the intrinsic are connected directly with a
// chain:
// t1: i32,ch = int.load ..., ..., ..., Loc, ... // <-- C
// t2: i32,ch = load t1:1, Loc, ...
SDNode *C = Ch.getNode();
if (C->getOpcode() != ISD::INTRINSIC_W_CHAIN)
return false;
// The second load can only be eliminated if its extension type matches
// that of the load instruction corresponding to the intrinsic. The user
// can provide an address of an unsigned variable to store the result of
// a sign-extending intrinsic into (or the other way around).
ISD::LoadExtType IntExt;
switch (cast<ConstantSDNode>(C->getOperand(1))->getZExtValue()) {
case Intrinsic::hexagon_brev_ldub:
case Intrinsic::hexagon_brev_lduh:
case Intrinsic::hexagon_circ_ldub:
case Intrinsic::hexagon_circ_lduh:
IntExt = ISD::ZEXTLOAD;
break;
case Intrinsic::hexagon_brev_ldw:
case Intrinsic::hexagon_brev_ldd:
case Intrinsic::hexagon_circ_ldw:
case Intrinsic::hexagon_circ_ldd:
IntExt = ISD::NON_EXTLOAD;
break;
default:
IntExt = ISD::SEXTLOAD;
break;
}
if (N->getExtensionType() != IntExt)
return false;
// Make sure the target location for the loaded value in the load intrinsic
// is the location from which LD (or N) is loading.
if (C->getNumOperands() < 4 || Loc.getNode() != C->getOperand(3).getNode())
return false;
if (MachineSDNode *L = LoadInstrForLoadIntrinsic(C)) {
SDNode *S = StoreInstrForLoadIntrinsic(L, C);
SDValue F[] = { SDValue(N,0), SDValue(N,1), SDValue(C,0), SDValue(C,1) };
SDValue T[] = { SDValue(L,0), SDValue(S,0), SDValue(L,1), SDValue(S,0) };
ReplaceUses(F, T, array_lengthof(T));
// This transformation will leave the intrinsic dead. If it remains in
// the DAG, the selection code will see it again, but without the load,
// and it will generate a store that is normally required for it.
CurDAG->RemoveDeadNode(C);
return true;
}
return false;
}
void HexagonDAGToDAGISel::SelectLoad(SDNode *N) {
SDLoc dl(N);
LoadSDNode *LD = cast<LoadSDNode>(N);
ISD::MemIndexedMode AM = LD->getAddressingMode();
// Handle indexed loads.
if (AM != ISD::UNINDEXED) {
SelectIndexedLoad(LD, dl);
return;
}
// Handle patterns using circ/brev load intrinsics.
if (tryLoadOfLoadIntrinsic(LD))
return;
SelectCode(LD);
}
void HexagonDAGToDAGISel::SelectIndexedStore(StoreSDNode *ST, const SDLoc &dl) {
SDValue Chain = ST->getChain();
SDValue Base = ST->getBasePtr();
SDValue Offset = ST->getOffset();
SDValue Value = ST->getValue();
// Get the constant value.
int32_t Inc = cast<ConstantSDNode>(Offset.getNode())->getSExtValue();
EVT StoredVT = ST->getMemoryVT();
EVT ValueVT = Value.getValueType();
bool IsValidInc = HII->isValidAutoIncImm(StoredVT, Inc);
unsigned Opcode = 0;
assert(StoredVT.isSimple());
switch (StoredVT.getSimpleVT().SimpleTy) {
case MVT::i8:
Opcode = IsValidInc ? Hexagon::S2_storerb_pi : Hexagon::S2_storerb_io;
break;
case MVT::i16:
Opcode = IsValidInc ? Hexagon::S2_storerh_pi : Hexagon::S2_storerh_io;
break;
case MVT::i32:
Opcode = IsValidInc ? Hexagon::S2_storeri_pi : Hexagon::S2_storeri_io;
break;
case MVT::i64:
Opcode = IsValidInc ? Hexagon::S2_storerd_pi : Hexagon::S2_storerd_io;
break;
case MVT::v64i8:
case MVT::v32i16:
case MVT::v16i32:
case MVT::v8i64:
case MVT::v128i8:
case MVT::v64i16:
case MVT::v32i32:
case MVT::v16i64:
if (isAlignedMemNode(ST)) {
if (ST->isNonTemporal())
Opcode = IsValidInc ? Hexagon::V6_vS32b_nt_pi : Hexagon::V6_vS32b_nt_ai;
else
Opcode = IsValidInc ? Hexagon::V6_vS32b_pi : Hexagon::V6_vS32b_ai;
} else {
Opcode = IsValidInc ? Hexagon::V6_vS32Ub_pi : Hexagon::V6_vS32Ub_ai;
}
break;
default:
llvm_unreachable("Unexpected memory type in indexed store");
}
if (ST->isTruncatingStore() && ValueVT.getSizeInBits() == 64) {
assert(StoredVT.getSizeInBits() < 64 && "Not a truncating store");
Value = CurDAG->getTargetExtractSubreg(Hexagon::isub_lo,
dl, MVT::i32, Value);
}
SDValue IncV = CurDAG->getTargetConstant(Inc, dl, MVT::i32);
MachineSDNode::mmo_iterator MemOp = MF->allocateMemRefsArray(1);
MemOp[0] = ST->getMemOperand();
// Next address Chain
SDValue From[2] = { SDValue(ST,0), SDValue(ST,1) };
SDValue To[2];
if (IsValidInc) {
// Build post increment store.
SDValue Ops[] = { Base, IncV, Value, Chain };
MachineSDNode *S = CurDAG->getMachineNode(Opcode, dl, MVT::i32, MVT::Other,
Ops);
S->setMemRefs(MemOp, MemOp + 1);
To[0] = SDValue(S, 0);
To[1] = SDValue(S, 1);
} else {
SDValue Zero = CurDAG->getTargetConstant(0, dl, MVT::i32);
SDValue Ops[] = { Base, Zero, Value, Chain };
MachineSDNode *S = CurDAG->getMachineNode(Opcode, dl, MVT::Other, Ops);
S->setMemRefs(MemOp, MemOp + 1);
To[1] = SDValue(S, 0);
MachineSDNode *A = CurDAG->getMachineNode(Hexagon::A2_addi, dl, MVT::i32,
Base, IncV);
To[0] = SDValue(A, 0);
}
ReplaceUses(From, To, 2);
CurDAG->RemoveDeadNode(ST);
}
void HexagonDAGToDAGISel::SelectStore(SDNode *N) {
SDLoc dl(N);
StoreSDNode *ST = cast<StoreSDNode>(N);
ISD::MemIndexedMode AM = ST->getAddressingMode();
// Handle indexed stores.
if (AM != ISD::UNINDEXED) {
SelectIndexedStore(ST, dl);
return;
}
SelectCode(ST);
}
void HexagonDAGToDAGISel::SelectSHL(SDNode *N) {
SDLoc dl(N);
SDValue Shl_0 = N->getOperand(0);
SDValue Shl_1 = N->getOperand(1);
auto Default = [this,N] () -> void { SelectCode(N); };
if (N->getValueType(0) != MVT::i32 || Shl_1.getOpcode() != ISD::Constant)
return Default();
// RHS is const.
int32_t ShlConst = cast<ConstantSDNode>(Shl_1)->getSExtValue();
if (Shl_0.getOpcode() == ISD::MUL) {
SDValue Mul_0 = Shl_0.getOperand(0); // Val
SDValue Mul_1 = Shl_0.getOperand(1); // Const
// RHS of mul is const.
if (ConstantSDNode *C = dyn_cast<ConstantSDNode>(Mul_1)) {
int32_t ValConst = C->getSExtValue() << ShlConst;
if (isInt<9>(ValConst)) {
SDValue Val = CurDAG->getTargetConstant(ValConst, dl, MVT::i32);
SDNode *Result = CurDAG->getMachineNode(Hexagon::M2_mpysmi, dl,
MVT::i32, Mul_0, Val);
ReplaceNode(N, Result);
return;
}
}
return Default();
}
if (Shl_0.getOpcode() == ISD::SUB) {
SDValue Sub_0 = Shl_0.getOperand(0); // Const 0
SDValue Sub_1 = Shl_0.getOperand(1); // Val
if (ConstantSDNode *C1 = dyn_cast<ConstantSDNode>(Sub_0)) {
if (C1->getSExtValue() != 0 || Sub_1.getOpcode() != ISD::SHL)
return Default();
SDValue Shl2_0 = Sub_1.getOperand(0); // Val
SDValue Shl2_1 = Sub_1.getOperand(1); // Const
if (ConstantSDNode *C2 = dyn_cast<ConstantSDNode>(Shl2_1)) {
int32_t ValConst = 1 << (ShlConst + C2->getSExtValue());
if (isInt<9>(-ValConst)) {
SDValue Val = CurDAG->getTargetConstant(-ValConst, dl, MVT::i32);
SDNode *Result = CurDAG->getMachineNode(Hexagon::M2_mpysmi, dl,
MVT::i32, Shl2_0, Val);
ReplaceNode(N, Result);
return;
}
}
}
}
return Default();
}
//
// If there is an zero_extend followed an intrinsic in DAG (this means - the
// result of the intrinsic is predicate); convert the zero_extend to
// transfer instruction.
//
// Zero extend -> transfer is lowered here. Otherwise, zero_extend will be
// converted into a MUX as predicate registers defined as 1 bit in the
// compiler. Architecture defines them as 8-bit registers.
// We want to preserve all the lower 8-bits and, not just 1 LSB bit.
//
void HexagonDAGToDAGISel::SelectZeroExtend(SDNode *N) {
SDLoc dl(N);
SDValue Op0 = N->getOperand(0);
EVT OpVT = Op0.getValueType();
unsigned OpBW = OpVT.getSizeInBits();
// Special handling for zero-extending a vector of booleans.
if (OpVT.isVector() && OpVT.getVectorElementType() == MVT::i1 && OpBW <= 64) {
SDNode *Mask = CurDAG->getMachineNode(Hexagon::C2_mask, dl, MVT::i64, Op0);
unsigned NE = OpVT.getVectorNumElements();
EVT ExVT = N->getValueType(0);
unsigned ES = ExVT.getScalarSizeInBits();
uint64_t MV = 0, Bit = 1;
for (unsigned i = 0; i < NE; ++i) {
MV |= Bit;
Bit <<= ES;
}
SDValue Ones = CurDAG->getTargetConstant(MV, dl, MVT::i64);
SDNode *OnesReg = CurDAG->getMachineNode(Hexagon::CONST64, dl,
MVT::i64, Ones);
if (ExVT.getSizeInBits() == 32) {
SDNode *And = CurDAG->getMachineNode(Hexagon::A2_andp, dl, MVT::i64,
SDValue(Mask,0), SDValue(OnesReg,0));
SDValue SubR = CurDAG->getTargetConstant(Hexagon::isub_lo, dl, MVT::i32);
ReplaceNode(N, CurDAG->getMachineNode(Hexagon::EXTRACT_SUBREG, dl, ExVT,
SDValue(And, 0), SubR));
return;
}
ReplaceNode(N,
CurDAG->getMachineNode(Hexagon::A2_andp, dl, ExVT,
SDValue(Mask, 0), SDValue(OnesReg, 0)));
return;
}
SDNode *Int = N->getOperand(0).getNode();
if ((Int->getOpcode() == ISD::INTRINSIC_WO_CHAIN)) {
unsigned ID = cast<ConstantSDNode>(Int->getOperand(0))->getZExtValue();
if (doesIntrinsicReturnPredicate(ID)) {
// Now we need to differentiate target data types.
if (N->getValueType(0) == MVT::i64) {
// Convert the zero_extend to Rs = Pd followed by A2_combinew(0,Rs).
SDValue TargetConst0 = CurDAG->getTargetConstant(0, dl, MVT::i32);
SDNode *Result_1 = CurDAG->getMachineNode(Hexagon::C2_tfrpr, dl,
MVT::i32, SDValue(Int, 0));
SDNode *Result_2 = CurDAG->getMachineNode(Hexagon::A2_tfrsi, dl,
MVT::i32, TargetConst0);
SDNode *Result_3 = CurDAG->getMachineNode(Hexagon::A2_combinew, dl,
MVT::i64, MVT::Other,
SDValue(Result_2, 0),
SDValue(Result_1, 0));
ReplaceNode(N, Result_3);
return;
}
if (N->getValueType(0) == MVT::i32) {
// Convert the zero_extend to Rs = Pd
SDNode* RsPd = CurDAG->getMachineNode(Hexagon::C2_tfrpr, dl,
MVT::i32, SDValue(Int, 0));
ReplaceNode(N, RsPd);
return;
}
llvm_unreachable("Unexpected value type");
}
}
SelectCode(N);
}
//
// Handling intrinsics for circular load and bitreverse load.
//
void HexagonDAGToDAGISel::SelectIntrinsicWChain(SDNode *N) {
if (MachineSDNode *L = LoadInstrForLoadIntrinsic(N)) {
StoreInstrForLoadIntrinsic(L, N);
CurDAG->RemoveDeadNode(N);
return;
}
SelectCode(N);
}
void HexagonDAGToDAGISel::SelectIntrinsicWOChain(SDNode *N) {
unsigned IID = cast<ConstantSDNode>(N->getOperand(0))->getZExtValue();
unsigned Bits;
switch (IID) {
case Intrinsic::hexagon_S2_vsplatrb:
Bits = 8;
break;
case Intrinsic::hexagon_S2_vsplatrh:
Bits = 16;
break;
default:
SelectCode(N);
return;
}
SDValue V = N->getOperand(1);
SDValue U;
if (keepsLowBits(V, Bits, U)) {
SDValue R = CurDAG->getNode(N->getOpcode(), SDLoc(N), N->getValueType(0),
N->getOperand(0), U);
ReplaceNode(N, R.getNode());
SelectCode(R.getNode());
return;
}
SelectCode(N);
}
//
// Map floating point constant values.
//
void HexagonDAGToDAGISel::SelectConstantFP(SDNode *N) {
SDLoc dl(N);
ConstantFPSDNode *CN = dyn_cast<ConstantFPSDNode>(N);
APInt A = CN->getValueAPF().bitcastToAPInt();
if (N->getValueType(0) == MVT::f32) {
SDValue V = CurDAG->getTargetConstant(A.getZExtValue(), dl, MVT::i32);
ReplaceNode(N, CurDAG->getMachineNode(Hexagon::A2_tfrsi, dl, MVT::f32, V));
return;
}
if (N->getValueType(0) == MVT::f64) {
SDValue V = CurDAG->getTargetConstant(A.getZExtValue(), dl, MVT::i64);
ReplaceNode(N, CurDAG->getMachineNode(Hexagon::CONST64, dl, MVT::f64, V));
return;
}
SelectCode(N);
}
//
// Map boolean values.
//
void HexagonDAGToDAGISel::SelectConstant(SDNode *N) {
if (N->getValueType(0) == MVT::i1) {
assert(!(cast<ConstantSDNode>(N)->getZExtValue() >> 1));
unsigned Opc = (cast<ConstantSDNode>(N)->getSExtValue() != 0)
? Hexagon::PS_true
: Hexagon::PS_false;
ReplaceNode(N, CurDAG->getMachineNode(Opc, SDLoc(N), MVT::i1));
return;
}
SelectCode(N);
}
void HexagonDAGToDAGISel::SelectFrameIndex(SDNode *N) {
MachineFrameInfo &MFI = MF->getFrameInfo();
const HexagonFrameLowering *HFI = HST->getFrameLowering();
int FX = cast<FrameIndexSDNode>(N)->getIndex();
unsigned StkA = HFI->getStackAlignment();
unsigned MaxA = MFI.getMaxAlignment();
SDValue FI = CurDAG->getTargetFrameIndex(FX, MVT::i32);
SDLoc DL(N);
SDValue Zero = CurDAG->getTargetConstant(0, DL, MVT::i32);
SDNode *R = nullptr;
// Use PS_fi when:
// - the object is fixed, or
// - there are no objects with higher-than-default alignment, or
// - there are no dynamically allocated objects.
// Otherwise, use PS_fia.
if (FX < 0 || MaxA <= StkA || !MFI.hasVarSizedObjects()) {
R = CurDAG->getMachineNode(Hexagon::PS_fi, DL, MVT::i32, FI, Zero);
} else {
auto &HMFI = *MF->getInfo<HexagonMachineFunctionInfo>();
unsigned AR = HMFI.getStackAlignBaseVReg();
SDValue CH = CurDAG->getEntryNode();
SDValue Ops[] = { CurDAG->getCopyFromReg(CH, DL, AR, MVT::i32), FI, Zero };
R = CurDAG->getMachineNode(Hexagon::PS_fia, DL, MVT::i32, Ops);
}
ReplaceNode(N, R);
}
void HexagonDAGToDAGISel::SelectBitcast(SDNode *N) {
EVT SVT = N->getOperand(0).getValueType();
EVT DVT = N->getValueType(0);
if (!SVT.isVector() || !DVT.isVector() ||
SVT.getVectorElementType() == MVT::i1 ||
DVT.getVectorElementType() == MVT::i1 ||
SVT.getSizeInBits() != DVT.getSizeInBits()) {
SelectCode(N);
return;
}
CurDAG->ReplaceAllUsesOfValueWith(SDValue(N,0), N->getOperand(0));
CurDAG->RemoveDeadNode(N);
}
void HexagonDAGToDAGISel::Select(SDNode *N) {
if (N->isMachineOpcode())
return N->setNodeId(-1); // Already selected.
switch (N->getOpcode()) {
case ISD::Constant: return SelectConstant(N);
case ISD::ConstantFP: return SelectConstantFP(N);
case ISD::FrameIndex: return SelectFrameIndex(N);
case ISD::BITCAST: return SelectBitcast(N);
case ISD::SHL: return SelectSHL(N);
case ISD::LOAD: return SelectLoad(N);
case ISD::STORE: return SelectStore(N);
case ISD::ZERO_EXTEND: return SelectZeroExtend(N);
case ISD::INTRINSIC_W_CHAIN: return SelectIntrinsicWChain(N);
case ISD::INTRINSIC_WO_CHAIN: return SelectIntrinsicWOChain(N);
}
SelectCode(N);
}
bool HexagonDAGToDAGISel::
SelectInlineAsmMemoryOperand(const SDValue &Op, unsigned ConstraintID,
std::vector<SDValue> &OutOps) {
SDValue Inp = Op, Res;
switch (ConstraintID) {
default:
return true;
case InlineAsm::Constraint_i:
case InlineAsm::Constraint_o: // Offsetable.
case InlineAsm::Constraint_v: // Not offsetable.
case InlineAsm::Constraint_m: // Memory.
if (SelectAddrFI(Inp, Res))
OutOps.push_back(Res);
else
OutOps.push_back(Inp);
break;
}
OutOps.push_back(CurDAG->getTargetConstant(0, SDLoc(Op), MVT::i32));
return false;
}
static bool isMemOPCandidate(SDNode *I, SDNode *U) {
// I is an operand of U. Check if U is an arithmetic (binary) operation
// usable in a memop, where the other operand is a loaded value, and the
// result of U is stored in the same location.
if (!U->hasOneUse())
return false;
unsigned Opc = U->getOpcode();
switch (Opc) {
case ISD::ADD:
case ISD::SUB:
case ISD::AND:
case ISD::OR:
break;
default:
return false;
}
SDValue S0 = U->getOperand(0);
SDValue S1 = U->getOperand(1);
SDValue SY = (S0.getNode() == I) ? S1 : S0;
SDNode *UUse = *U->use_begin();
if (UUse->getNumValues() != 1)
return false;
// Check if one of the inputs to U is a load instruction and the output
// is used by a store instruction. If so and they also have the same
// base pointer, then don't preoprocess this node sequence as it
// can be matched to a memop.
SDNode *SYNode = SY.getNode();
if (UUse->getOpcode() == ISD::STORE && SYNode->getOpcode() == ISD::LOAD) {
SDValue LDBasePtr = cast<MemSDNode>(SYNode)->getBasePtr();
SDValue STBasePtr = cast<MemSDNode>(UUse)->getBasePtr();
if (LDBasePtr == STBasePtr)
return true;
}
return false;
}
// Transform: (or (select c x 0) z) -> (select c (or x z) z)
// (or (select c 0 y) z) -> (select c z (or y z))
void HexagonDAGToDAGISel::ppSimplifyOrSelect0(std::vector<SDNode*> &&Nodes) {
SelectionDAG &DAG = *CurDAG;
for (auto I : Nodes) {
if (I->getOpcode() != ISD::OR)
continue;
auto IsZero = [] (const SDValue &V) -> bool {
if (ConstantSDNode *SC = dyn_cast<ConstantSDNode>(V.getNode()))
return SC->isNullValue();
return false;
};
auto IsSelect0 = [IsZero] (const SDValue &Op) -> bool {
if (Op.getOpcode() != ISD::SELECT)
return false;
return IsZero(Op.getOperand(1)) || IsZero(Op.getOperand(2));
};
SDValue N0 = I->getOperand(0), N1 = I->getOperand(1);
EVT VT = I->getValueType(0);
bool SelN0 = IsSelect0(N0);
SDValue SOp = SelN0 ? N0 : N1;
SDValue VOp = SelN0 ? N1 : N0;
if (SOp.getOpcode() == ISD::SELECT && SOp.getNode()->hasOneUse()) {
SDValue SC = SOp.getOperand(0);
SDValue SX = SOp.getOperand(1);
SDValue SY = SOp.getOperand(2);
SDLoc DLS = SOp;
if (IsZero(SY)) {
SDValue NewOr = DAG.getNode(ISD::OR, DLS, VT, SX, VOp);
SDValue NewSel = DAG.getNode(ISD::SELECT, DLS, VT, SC, NewOr, VOp);
DAG.ReplaceAllUsesWith(I, NewSel.getNode());
} else if (IsZero(SX)) {
SDValue NewOr = DAG.getNode(ISD::OR, DLS, VT, SY, VOp);
SDValue NewSel = DAG.getNode(ISD::SELECT, DLS, VT, SC, VOp, NewOr);
DAG.ReplaceAllUsesWith(I, NewSel.getNode());
}
}
}
}
// Transform: (store ch val (add x (add (shl y c) e)))
// to: (store ch val (add x (shl (add y d) c))),
// where e = (shl d c) for some integer d.
// The purpose of this is to enable generation of loads/stores with
// shifted addressing mode, i.e. mem(x+y<<#c). For that, the shift
// value c must be 0, 1 or 2.
void HexagonDAGToDAGISel::ppAddrReorderAddShl(std::vector<SDNode*> &&Nodes) {
SelectionDAG &DAG = *CurDAG;
for (auto I : Nodes) {
if (I->getOpcode() != ISD::STORE)
continue;
// I matched: (store ch val Off)
SDValue Off = I->getOperand(2);
// Off needs to match: (add x (add (shl y c) (shl d c))))
if (Off.getOpcode() != ISD::ADD)
continue;
// Off matched: (add x T0)
SDValue T0 = Off.getOperand(1);
// T0 needs to match: (add T1 T2):
if (T0.getOpcode() != ISD::ADD)
continue;
// T0 matched: (add T1 T2)
SDValue T1 = T0.getOperand(0);
SDValue T2 = T0.getOperand(1);
// T1 needs to match: (shl y c)
if (T1.getOpcode() != ISD::SHL)
continue;
SDValue C = T1.getOperand(1);
ConstantSDNode *CN = dyn_cast<ConstantSDNode>(C.getNode());
if (CN == nullptr)
continue;
unsigned CV = CN->getZExtValue();
if (CV > 2)
continue;
// T2 needs to match e, where e = (shl d c) for some d.
ConstantSDNode *EN = dyn_cast<ConstantSDNode>(T2.getNode());
if (EN == nullptr)
continue;
unsigned EV = EN->getZExtValue();
if (EV % (1 << CV) != 0)
continue;
unsigned DV = EV / (1 << CV);
// Replace T0 with: (shl (add y d) c)
SDLoc DL = SDLoc(I);
EVT VT = T0.getValueType();
SDValue D = DAG.getConstant(DV, DL, VT);
// NewAdd = (add y d)
SDValue NewAdd = DAG.getNode(ISD::ADD, DL, VT, T1.getOperand(0), D);
// NewShl = (shl NewAdd c)
SDValue NewShl = DAG.getNode(ISD::SHL, DL, VT, NewAdd, C);
ReplaceNode(T0.getNode(), NewShl.getNode());
}
}
// Transform: (load ch (add x (and (srl y c) Mask)))
// to: (load ch (add x (shl (srl y d) d-c)))
// where
// Mask = 00..0 111..1 0.0
// | | +-- d-c 0s, and d-c is 0, 1 or 2.
// | +-------- 1s
// +-------------- at most c 0s
// Motivating example:
// DAG combiner optimizes (add x (shl (srl y 5) 2))
// to (add x (and (srl y 3) 1FFFFFFC))
// which results in a constant-extended and(##...,lsr). This transformation
// undoes this simplification for cases where the shl can be folded into
// an addressing mode.
void HexagonDAGToDAGISel::ppAddrRewriteAndSrl(std::vector<SDNode*> &&Nodes) {
SelectionDAG &DAG = *CurDAG;
for (SDNode *N : Nodes) {
unsigned Opc = N->getOpcode();
if (Opc != ISD::LOAD && Opc != ISD::STORE)
continue;
SDValue Addr = Opc == ISD::LOAD ? N->getOperand(1) : N->getOperand(2);
// Addr must match: (add x T0)
if (Addr.getOpcode() != ISD::ADD)
continue;
SDValue T0 = Addr.getOperand(1);
// T0 must match: (and T1 Mask)
if (T0.getOpcode() != ISD::AND)
continue;
// We have an AND.
//
// Check the first operand. It must be: (srl y c).
SDValue S = T0.getOperand(0);
if (S.getOpcode() != ISD::SRL)
continue;
ConstantSDNode *SN = dyn_cast<ConstantSDNode>(S.getOperand(1).getNode());
if (SN == nullptr)
continue;
if (SN->getAPIntValue().getBitWidth() != 32)
continue;
uint32_t CV = SN->getZExtValue();
// Check the second operand: the supposed mask.
ConstantSDNode *MN = dyn_cast<ConstantSDNode>(T0.getOperand(1).getNode());
if (MN == nullptr)
continue;
if (MN->getAPIntValue().getBitWidth() != 32)
continue;
uint32_t Mask = MN->getZExtValue();
// Examine the mask.
uint32_t TZ = countTrailingZeros(Mask);
uint32_t M1 = countTrailingOnes(Mask >> TZ);
uint32_t LZ = countLeadingZeros(Mask);
// Trailing zeros + middle ones + leading zeros must equal the width.
if (TZ + M1 + LZ != 32)
continue;
// The number of trailing zeros will be encoded in the addressing mode.
if (TZ > 2)
continue;
// The number of leading zeros must be at most c.
if (LZ > CV)
continue;
// All looks good.
SDValue Y = S.getOperand(0);
EVT VT = Addr.getValueType();
SDLoc dl(S);
// TZ = D-C, so D = TZ+C.
SDValue D = DAG.getConstant(TZ+CV, dl, VT);
SDValue DC = DAG.getConstant(TZ, dl, VT);
SDValue NewSrl = DAG.getNode(ISD::SRL, dl, VT, Y, D);
SDValue NewShl = DAG.getNode(ISD::SHL, dl, VT, NewSrl, DC);
ReplaceNode(T0.getNode(), NewShl.getNode());
}
}
// Transform: (op ... (zext i1 c) ...) -> (select c (op ... 0 ...)
// (op ... 1 ...))
void HexagonDAGToDAGISel::ppHoistZextI1(std::vector<SDNode*> &&Nodes) {
SelectionDAG &DAG = *CurDAG;
for (SDNode *N : Nodes) {
unsigned Opc = N->getOpcode();
if (Opc != ISD::ZERO_EXTEND)
continue;
SDValue OpI1 = N->getOperand(0);
EVT OpVT = OpI1.getValueType();
if (!OpVT.isSimple() || OpVT.getSimpleVT() != MVT::i1)
continue;
for (auto I = N->use_begin(), E = N->use_end(); I != E; ++I) {
SDNode *U = *I;
if (U->getNumValues() != 1)
continue;
EVT UVT = U->getValueType(0);
if (!UVT.isSimple() || !UVT.isInteger() || UVT.getSimpleVT() == MVT::i1)
continue;
if (isMemOPCandidate(N, U))
continue;
// Potentially simplifiable operation.
unsigned I1N = I.getOperandNo();
SmallVector<SDValue,2> Ops(U->getNumOperands());
for (unsigned i = 0, n = U->getNumOperands(); i != n; ++i)
Ops[i] = U->getOperand(i);
EVT BVT = Ops[I1N].getValueType();
SDLoc dl(U);
SDValue C0 = DAG.getConstant(0, dl, BVT);
SDValue C1 = DAG.getConstant(1, dl, BVT);
SDValue If0, If1;
if (isa<MachineSDNode>(U)) {
unsigned UseOpc = U->getMachineOpcode();
Ops[I1N] = C0;
If0 = SDValue(DAG.getMachineNode(UseOpc, dl, UVT, Ops), 0);
Ops[I1N] = C1;
If1 = SDValue(DAG.getMachineNode(UseOpc, dl, UVT, Ops), 0);
} else {
unsigned UseOpc = U->getOpcode();
Ops[I1N] = C0;
If0 = DAG.getNode(UseOpc, dl, UVT, Ops);
Ops[I1N] = C1;
If1 = DAG.getNode(UseOpc, dl, UVT, Ops);
}
SDValue Sel = DAG.getNode(ISD::SELECT, dl, UVT, OpI1, If1, If0);
DAG.ReplaceAllUsesWith(U, Sel.getNode());
}
}
}
void HexagonDAGToDAGISel::PreprocessISelDAG() {
// Repack all nodes before calling each preprocessing function,
// because each of them can modify the set of nodes.
auto getNodes = [this] () -> std::vector<SDNode*> {
std::vector<SDNode*> T;
T.reserve(CurDAG->allnodes_size());
for (SDNode &N : CurDAG->allnodes())
T.push_back(&N);
return T;
};
// Transform: (or (select c x 0) z) -> (select c (or x z) z)
// (or (select c 0 y) z) -> (select c z (or y z))
ppSimplifyOrSelect0(getNodes());
// Transform: (store ch val (add x (add (shl y c) e)))
// to: (store ch val (add x (shl (add y d) c))),
// where e = (shl d c) for some integer d.
// The purpose of this is to enable generation of loads/stores with
// shifted addressing mode, i.e. mem(x+y<<#c). For that, the shift
// value c must be 0, 1 or 2.
ppAddrReorderAddShl(getNodes());
// Transform: (load ch (add x (and (srl y c) Mask)))
// to: (load ch (add x (shl (srl y d) d-c)))
// where
// Mask = 00..0 111..1 0.0
// | | +-- d-c 0s, and d-c is 0, 1 or 2.
// | +-------- 1s
// +-------------- at most c 0s
// Motivating example:
// DAG combiner optimizes (add x (shl (srl y 5) 2))
// to (add x (and (srl y 3) 1FFFFFFC))
// which results in a constant-extended and(##...,lsr). This transformation
// undoes this simplification for cases where the shl can be folded into
// an addressing mode.
ppAddrRewriteAndSrl(getNodes());
// Transform: (op ... (zext i1 c) ...) -> (select c (op ... 0 ...)
// (op ... 1 ...))
ppHoistZextI1(getNodes());
DEBUG_WITH_TYPE("isel", {
dbgs() << "Preprocessed (Hexagon) selection DAG:";
CurDAG->dump();
});
if (EnableAddressRebalancing) {
rebalanceAddressTrees();
DEBUG_WITH_TYPE("isel", {
dbgs() << "Address tree balanced selection DAG:";
CurDAG->dump();
});
}
}
void HexagonDAGToDAGISel::EmitFunctionEntryCode() {
auto &HST = static_cast<const HexagonSubtarget&>(MF->getSubtarget());
auto &HFI = *HST.getFrameLowering();
if (!HFI.needsAligna(*MF))
return;
MachineFrameInfo &MFI = MF->getFrameInfo();
MachineBasicBlock *EntryBB = &MF->front();
unsigned AR = FuncInfo->CreateReg(MVT::i32);
unsigned MaxA = MFI.getMaxAlignment();
BuildMI(EntryBB, DebugLoc(), HII->get(Hexagon::PS_aligna), AR)
.addImm(MaxA);
MF->getInfo<HexagonMachineFunctionInfo>()->setStackAlignBaseVReg(AR);
}
// Match a frame index that can be used in an addressing mode.
bool HexagonDAGToDAGISel::SelectAddrFI(SDValue &N, SDValue &R) {
if (N.getOpcode() != ISD::FrameIndex)
return false;
auto &HFI = *HST->getFrameLowering();
MachineFrameInfo &MFI = MF->getFrameInfo();
int FX = cast<FrameIndexSDNode>(N)->getIndex();
if (!MFI.isFixedObjectIndex(FX) && HFI.needsAligna(*MF))
return false;
R = CurDAG->getTargetFrameIndex(FX, MVT::i32);
return true;
}
inline bool HexagonDAGToDAGISel::SelectAddrGA(SDValue &N, SDValue &R) {
return SelectGlobalAddress(N, R, false, 0);
}
inline bool HexagonDAGToDAGISel::SelectAddrGP(SDValue &N, SDValue &R) {
return SelectGlobalAddress(N, R, true, 0);
}
inline bool HexagonDAGToDAGISel::SelectAnyImm(SDValue &N, SDValue &R) {
return SelectAnyImmediate(N, R, 0);
}
inline bool HexagonDAGToDAGISel::SelectAnyImm0(SDValue &N, SDValue &R) {
return SelectAnyImmediate(N, R, 0);
}
inline bool HexagonDAGToDAGISel::SelectAnyImm1(SDValue &N, SDValue &R) {
return SelectAnyImmediate(N, R, 1);
}
inline bool HexagonDAGToDAGISel::SelectAnyImm2(SDValue &N, SDValue &R) {
return SelectAnyImmediate(N, R, 2);
}
inline bool HexagonDAGToDAGISel::SelectAnyImm3(SDValue &N, SDValue &R) {
return SelectAnyImmediate(N, R, 3);
}
inline bool HexagonDAGToDAGISel::SelectAnyInt(SDValue &N, SDValue &R) {
EVT T = N.getValueType();
if (!T.isInteger() || T.getSizeInBits() != 32 || !isa<ConstantSDNode>(N))
return false;
R = N;
return true;
}
bool HexagonDAGToDAGISel::SelectAnyImmediate(SDValue &N, SDValue &R,
uint32_t LogAlign) {
auto IsAligned = [LogAlign] (uint64_t V) -> bool {
return alignTo(V, (uint64_t)1 << LogAlign) == V;
};
switch (N.getOpcode()) {
case ISD::Constant: {
if (N.getValueType() != MVT::i32)
return false;
int32_t V = cast<const ConstantSDNode>(N)->getZExtValue();
if (!IsAligned(V))
return false;
R = CurDAG->getTargetConstant(V, SDLoc(N), N.getValueType());
return true;
}
case HexagonISD::JT:
case HexagonISD::CP:
// These are assumed to always be aligned at at least 8-byte boundary.
if (LogAlign > 3)
return false;
R = N.getOperand(0);
return true;
case ISD::ExternalSymbol:
// Symbols may be aligned at any boundary.
if (LogAlign > 0)
return false;
R = N;
return true;
case ISD::BlockAddress:
// Block address is always aligned at at least 4-byte boundary.
if (LogAlign > 2 || !IsAligned(cast<BlockAddressSDNode>(N)->getOffset()))
return false;
R = N;
return true;
}
if (SelectGlobalAddress(N, R, false, LogAlign) ||
SelectGlobalAddress(N, R, true, LogAlign))
return true;
return false;
}
bool HexagonDAGToDAGISel::SelectGlobalAddress(SDValue &N, SDValue &R,
bool UseGP, uint32_t LogAlign) {
auto IsAligned = [LogAlign] (uint64_t V) -> bool {
return alignTo(V, (uint64_t)1 << LogAlign) == V;
};
switch (N.getOpcode()) {
case ISD::ADD: {
SDValue N0 = N.getOperand(0);
SDValue N1 = N.getOperand(1);
unsigned GAOpc = N0.getOpcode();
if (UseGP && GAOpc != HexagonISD::CONST32_GP)
return false;
if (!UseGP && GAOpc != HexagonISD::CONST32)
return false;
if (ConstantSDNode *Const = dyn_cast<ConstantSDNode>(N1)) {
SDValue Addr = N0.getOperand(0);
// For the purpose of alignment, sextvalue and zextvalue are the same.
if (!IsAligned(Const->getZExtValue()))
return false;
if (GlobalAddressSDNode *GA = dyn_cast<GlobalAddressSDNode>(Addr)) {
if (GA->getOpcode() == ISD::TargetGlobalAddress) {
uint64_t NewOff = GA->getOffset() + (uint64_t)Const->getSExtValue();
R = CurDAG->getTargetGlobalAddress(GA->getGlobal(), SDLoc(Const),
N.getValueType(), NewOff);
return true;
}
}
}
break;
}
case HexagonISD::CP:
case HexagonISD::JT:
case HexagonISD::CONST32:
// The operand(0) of CONST32 is TargetGlobalAddress, which is what we
// want in the instruction.
if (!UseGP)
R = N.getOperand(0);
return !UseGP;
case HexagonISD::CONST32_GP:
if (UseGP)
R = N.getOperand(0);
return UseGP;
default:
return false;
}
return false;
}
bool HexagonDAGToDAGISel::DetectUseSxtw(SDValue &N, SDValue &R) {
// This (complex pattern) function is meant to detect a sign-extension
// i32->i64 on a per-operand basis. This would allow writing single
// patterns that would cover a number of combinations of different ways
// a sign-extensions could be written. For example:
// (mul (DetectUseSxtw x) (DetectUseSxtw y)) -> (M2_dpmpyss_s0 x y)
// could match either one of these:
// (mul (sext x) (sext_inreg y))
// (mul (sext-load *p) (sext_inreg y))
// (mul (sext_inreg x) (sext y))
// etc.
//
// The returned value will have type i64 and its low word will
// contain the value being extended. The high bits are not specified.
// The returned type is i64 because the original type of N was i64,
// but the users of this function should only use the low-word of the
// result, e.g.
// (mul sxtw:x, sxtw:y) -> (M2_dpmpyss_s0 (LoReg sxtw:x), (LoReg sxtw:y))
if (N.getValueType() != MVT::i64)
return false;
unsigned Opc = N.getOpcode();
switch (Opc) {
case ISD::SIGN_EXTEND:
case ISD::SIGN_EXTEND_INREG: {
// sext_inreg has the source type as a separate operand.
EVT T = Opc == ISD::SIGN_EXTEND
? N.getOperand(0).getValueType()
: cast<VTSDNode>(N.getOperand(1))->getVT();
if (T.getSizeInBits() != 32)
return false;
R = N.getOperand(0);
break;
}
case ISD::LOAD: {
LoadSDNode *L = cast<LoadSDNode>(N);
if (L->getExtensionType() != ISD::SEXTLOAD)
return false;
// All extending loads extend to i32, so even if the value in
// memory is shorter than 32 bits, it will be i32 after the load.
if (L->getMemoryVT().getSizeInBits() > 32)
return false;
R = N;
break;
}
default:
return false;
}
EVT RT = R.getValueType();
if (RT == MVT::i64)
return true;
assert(RT == MVT::i32);
// This is only to produce a value of type i64. Do not rely on the
// high bits produced by this.
const SDLoc &dl(N);
SDValue Ops[] = {
CurDAG->getTargetConstant(Hexagon::DoubleRegsRegClassID, dl, MVT::i32),
R, CurDAG->getTargetConstant(Hexagon::isub_hi, dl, MVT::i32),
R, CurDAG->getTargetConstant(Hexagon::isub_lo, dl, MVT::i32)
};
SDNode *T = CurDAG->getMachineNode(TargetOpcode::REG_SEQUENCE, dl,
MVT::i64, Ops);
R = SDValue(T, 0);
return true;
}
bool HexagonDAGToDAGISel::keepsLowBits(const SDValue &Val, unsigned NumBits,
SDValue &Src) {
unsigned Opc = Val.getOpcode();
switch (Opc) {
case ISD::SIGN_EXTEND:
case ISD::ZERO_EXTEND:
case ISD::ANY_EXTEND: {
const SDValue &Op0 = Val.getOperand(0);
EVT T = Op0.getValueType();
if (T.isInteger() && T.getSizeInBits() == NumBits) {
Src = Op0;
return true;
}
break;
}
case ISD::SIGN_EXTEND_INREG:
case ISD::AssertSext:
case ISD::AssertZext:
if (Val.getOperand(0).getValueType().isInteger()) {
VTSDNode *T = cast<VTSDNode>(Val.getOperand(1));
if (T->getVT().getSizeInBits() == NumBits) {
Src = Val.getOperand(0);
return true;
}
}
break;
case ISD::AND: {
// Check if this is an AND with NumBits of lower bits set to 1.
uint64_t Mask = (1 << NumBits) - 1;
if (ConstantSDNode *C = dyn_cast<ConstantSDNode>(Val.getOperand(0))) {
if (C->getZExtValue() == Mask) {
Src = Val.getOperand(1);
return true;
}
}
if (ConstantSDNode *C = dyn_cast<ConstantSDNode>(Val.getOperand(1))) {
if (C->getZExtValue() == Mask) {
Src = Val.getOperand(0);
return true;
}
}
break;
}
case ISD::OR:
case ISD::XOR: {
// OR/XOR with the lower NumBits bits set to 0.
uint64_t Mask = (1 << NumBits) - 1;
if (ConstantSDNode *C = dyn_cast<ConstantSDNode>(Val.getOperand(0))) {
if ((C->getZExtValue() & Mask) == 0) {
Src = Val.getOperand(1);
return true;
}
}
if (ConstantSDNode *C = dyn_cast<ConstantSDNode>(Val.getOperand(1))) {
if ((C->getZExtValue() & Mask) == 0) {
Src = Val.getOperand(0);
return true;
}
}
}
default:
break;
}
return false;
}
bool HexagonDAGToDAGISel::isOrEquivalentToAdd(const SDNode *N) const {
assert(N->getOpcode() == ISD::OR);
auto *C = dyn_cast<ConstantSDNode>(N->getOperand(1));
if (!C)
return false;
// Detect when "or" is used to add an offset to a stack object.
if (auto *FN = dyn_cast<FrameIndexSDNode>(N->getOperand(0))) {
MachineFrameInfo &MFI = MF->getFrameInfo();
unsigned A = MFI.getObjectAlignment(FN->getIndex());
assert(isPowerOf2_32(A));
int32_t Off = C->getSExtValue();
// If the alleged offset fits in the zero bits guaranteed by
// the alignment, then this or is really an add.
return (Off >= 0) && (((A-1) & Off) == unsigned(Off));
}
return false;
}
bool HexagonDAGToDAGISel::isAlignedMemNode(const MemSDNode *N) const {
return N->getAlignment() >= N->getMemoryVT().getStoreSize();
}
bool HexagonDAGToDAGISel::isSmallStackStore(const StoreSDNode *N) const {
unsigned StackSize = MF->getFrameInfo().estimateStackSize(*MF);
switch (N->getMemoryVT().getStoreSize()) {
case 1:
return StackSize <= 56; // 1*2^6 - 8
case 2:
return StackSize <= 120; // 2*2^6 - 8
case 4:
return StackSize <= 248; // 4*2^6 - 8
default:
return false;
}
}
// Return true when the given node fits in a positive half word.
bool HexagonDAGToDAGISel::isPositiveHalfWord(const SDNode *N) const {
if (const ConstantSDNode *CN = dyn_cast<const ConstantSDNode>(N)) {
int64_t V = CN->getSExtValue();
return V > 0 && isInt<16>(V);
}
if (N->getOpcode() == ISD::SIGN_EXTEND_INREG) {
const VTSDNode *VN = dyn_cast<const VTSDNode>(N->getOperand(1));
return VN->getVT().getSizeInBits() <= 16;
}
return false;
}
bool HexagonDAGToDAGISel::hasOneUse(const SDNode *N) const {
return !CheckSingleUse || N->hasOneUse();
}
////////////////////////////////////////////////////////////////////////////////
// Rebalancing of address calculation trees
static bool isOpcodeHandled(const SDNode *N) {
switch (N->getOpcode()) {
case ISD::ADD:
case ISD::MUL:
return true;
case ISD::SHL:
// We only handle constant shifts because these can be easily flattened
// into multiplications by 2^Op1.
return isa<ConstantSDNode>(N->getOperand(1).getNode());
default:
return false;
}
}
/// \brief Return the weight of an SDNode
int HexagonDAGToDAGISel::getWeight(SDNode *N) {
if (!isOpcodeHandled(N))
return 1;
assert(RootWeights.count(N) && "Cannot get weight of unseen root!");
assert(RootWeights[N] != -1 && "Cannot get weight of unvisited root!");
assert(RootWeights[N] != -2 && "Cannot get weight of RAWU'd root!");
return RootWeights[N];
}
int HexagonDAGToDAGISel::getHeight(SDNode *N) {
if (!isOpcodeHandled(N))
return 0;
assert(RootWeights.count(N) && RootWeights[N] >= 0 &&
"Cannot query height of unvisited/RAUW'd node!");
return RootHeights[N];
}
namespace {
struct WeightedLeaf {
SDValue Value;
int Weight;
int InsertionOrder;
WeightedLeaf() : Value(SDValue()) { }
WeightedLeaf(SDValue Value, int Weight, int InsertionOrder) :
Value(Value), Weight(Weight), InsertionOrder(InsertionOrder) {
assert(Weight >= 0 && "Weight must be >= 0");
}
static bool Compare(const WeightedLeaf &A, const WeightedLeaf &B) {
assert(A.Value.getNode() && B.Value.getNode());
return A.Weight == B.Weight ?
(A.InsertionOrder > B.InsertionOrder) :
(A.Weight > B.Weight);
}
};
/// A specialized priority queue for WeigthedLeaves. It automatically folds
/// constants and allows removal of non-top elements while maintaining the
/// priority order.
class LeafPrioQueue {
SmallVector<WeightedLeaf, 8> Q;
bool HaveConst;
WeightedLeaf ConstElt;
unsigned Opcode;
public:
bool empty() {
return (!HaveConst && Q.empty());
}
size_t size() {
return Q.size() + HaveConst;
}
bool hasConst() {
return HaveConst;
}
const WeightedLeaf &top() {
if (HaveConst)
return ConstElt;
return Q.front();
}
WeightedLeaf pop() {
if (HaveConst) {
HaveConst = false;
return ConstElt;
}
std::pop_heap(Q.begin(), Q.end(), WeightedLeaf::Compare);
return Q.pop_back_val();
}
void push(WeightedLeaf L, bool SeparateConst=true) {
if (!HaveConst && SeparateConst && isa<ConstantSDNode>(L.Value)) {
if (Opcode == ISD::MUL &&
cast<ConstantSDNode>(L.Value)->getSExtValue() == 1)
return;
if (Opcode == ISD::ADD &&
cast<ConstantSDNode>(L.Value)->getSExtValue() == 0)
return;
HaveConst = true;
ConstElt = L;
} else {
Q.push_back(L);
std::push_heap(Q.begin(), Q.end(), WeightedLeaf::Compare);
}
}
/// Push L to the bottom of the queue regardless of its weight. If L is
/// constant, it will not be folded with other constants in the queue.
void pushToBottom(WeightedLeaf L) {
L.Weight = 1000;
push(L, false);
}
/// Search for a SHL(x, [<=MaxAmount]) subtree in the queue, return the one of
/// lowest weight and remove it from the queue.
WeightedLeaf findSHL(uint64_t MaxAmount);
WeightedLeaf findMULbyConst();
LeafPrioQueue(unsigned Opcode) :
HaveConst(false), Opcode(Opcode) { }
};
} // end anonymous namespace
WeightedLeaf LeafPrioQueue::findSHL(uint64_t MaxAmount) {
int ResultPos;
WeightedLeaf Result;
for (int Pos = 0, End = Q.size(); Pos != End; ++Pos) {
const WeightedLeaf &L = Q[Pos];
const SDValue &Val = L.Value;
if (Val.getOpcode() != ISD::SHL ||
!isa<ConstantSDNode>(Val.getOperand(1)) ||
Val.getConstantOperandVal(1) > MaxAmount)
continue;
if (!Result.Value.getNode() || Result.Weight > L.Weight ||
(Result.Weight == L.Weight && Result.InsertionOrder > L.InsertionOrder))
{
Result = L;
ResultPos = Pos;
}
}
if (Result.Value.getNode()) {
Q.erase(&Q[ResultPos]);
std::make_heap(Q.begin(), Q.end(), WeightedLeaf::Compare);
}
return Result;
}
WeightedLeaf LeafPrioQueue::findMULbyConst() {
int ResultPos;
WeightedLeaf Result;
for (int Pos = 0, End = Q.size(); Pos != End; ++Pos) {
const WeightedLeaf &L = Q[Pos];
const SDValue &Val = L.Value;
if (Val.getOpcode() != ISD::MUL ||
!isa<ConstantSDNode>(Val.getOperand(1)) ||
Val.getConstantOperandVal(1) > 127)
continue;
if (!Result.Value.getNode() || Result.Weight > L.Weight ||
(Result.Weight == L.Weight && Result.InsertionOrder > L.InsertionOrder))
{
Result = L;
ResultPos = Pos;
}
}
if (Result.Value.getNode()) {
Q.erase(&Q[ResultPos]);
std::make_heap(Q.begin(), Q.end(), WeightedLeaf::Compare);
}
return Result;
}
SDValue HexagonDAGToDAGISel::getMultiplierForSHL(SDNode *N) {
uint64_t MulFactor = 1ull << N->getConstantOperandVal(1);
return CurDAG->getConstant(MulFactor, SDLoc(N),
N->getOperand(1).getValueType());
}
/// @returns the value x for which 2^x is a factor of Val
static unsigned getPowerOf2Factor(SDValue Val) {
if (Val.getOpcode() == ISD::MUL) {
unsigned MaxFactor = 0;
for (int i = 0; i < 2; ++i) {
ConstantSDNode *C = dyn_cast<ConstantSDNode>(Val.getOperand(i));
if (!C)
continue;
const APInt &CInt = C->getAPIntValue();
if (CInt.getBoolValue())
MaxFactor = CInt.countTrailingZeros();
}
return MaxFactor;
}
if (Val.getOpcode() == ISD::SHL) {
if (!isa<ConstantSDNode>(Val.getOperand(1).getNode()))
return 0;
return (unsigned) Val.getConstantOperandVal(1);
}
return 0;
}
/// @returns true if V>>Amount will eliminate V's operation on its child
static bool willShiftRightEliminate(SDValue V, unsigned Amount) {
if (V.getOpcode() == ISD::MUL) {
SDValue Ops[] = { V.getOperand(0), V.getOperand(1) };
for (int i = 0; i < 2; ++i)
if (isa<ConstantSDNode>(Ops[i].getNode()) &&
V.getConstantOperandVal(i) % (1ULL << Amount) == 0) {
uint64_t NewConst = V.getConstantOperandVal(i) >> Amount;
return (NewConst == 1);
}
} else if (V.getOpcode() == ISD::SHL) {
return (Amount == V.getConstantOperandVal(1));
}
return false;
}
SDValue HexagonDAGToDAGISel::factorOutPowerOf2(SDValue V, unsigned Power) {
SDValue Ops[] = { V.getOperand(0), V.getOperand(1) };
if (V.getOpcode() == ISD::MUL) {
for (int i=0; i < 2; ++i) {
if (isa<ConstantSDNode>(Ops[i].getNode()) &&
V.getConstantOperandVal(i) % ((uint64_t)1 << Power) == 0) {
uint64_t NewConst = V.getConstantOperandVal(i) >> Power;
if (NewConst == 1)
return Ops[!i];
Ops[i] = CurDAG->getConstant(NewConst,
SDLoc(V), V.getValueType());
break;
}
}
} else if (V.getOpcode() == ISD::SHL) {
uint64_t ShiftAmount = V.getConstantOperandVal(1);
if (ShiftAmount == Power)
return Ops[0];
Ops[1] = CurDAG->getConstant(ShiftAmount - Power,
SDLoc(V), V.getValueType());
}
return CurDAG->getNode(V.getOpcode(), SDLoc(V), V.getValueType(), Ops);
}
static bool isTargetConstant(const SDValue &V) {
return V.getOpcode() == HexagonISD::CONST32 ||
V.getOpcode() == HexagonISD::CONST32_GP;
}
unsigned HexagonDAGToDAGISel::getUsesInFunction(const Value *V) {
if (GAUsesInFunction.count(V))
return GAUsesInFunction[V];
unsigned Result = 0;
const Function *CurF = CurDAG->getMachineFunction().getFunction();
for (const User *U : V->users()) {
if (isa<Instruction>(U) &&
cast<Instruction>(U)->getParent()->getParent() == CurF)
++Result;
}
GAUsesInFunction[V] = Result;
return Result;
}
/// Note - After calling this, N may be dead. It may have been replaced by a
/// new node, so always use the returned value in place of N.
///
/// @returns The SDValue taking the place of N (which could be N if it is
/// unchanged)
SDValue HexagonDAGToDAGISel::balanceSubTree(SDNode *N, bool TopLevel) {
assert(RootWeights.count(N) && "Cannot balance non-root node.");
assert(RootWeights[N] != -2 && "This node was RAUW'd!");
assert(!TopLevel || N->getOpcode() == ISD::ADD);
// Return early if this node was already visited
if (RootWeights[N] != -1)
return SDValue(N, 0);
assert(isOpcodeHandled(N));
SDValue Op0 = N->getOperand(0);
SDValue Op1 = N->getOperand(1);
// Return early if the operands will remain unchanged or are all roots
if ((!isOpcodeHandled(Op0.getNode()) || RootWeights.count(Op0.getNode())) &&
(!isOpcodeHandled(Op1.getNode()) || RootWeights.count(Op1.getNode()))) {
SDNode *Op0N = Op0.getNode();
int Weight;
if (isOpcodeHandled(Op0N) && RootWeights[Op0N] == -1) {
Weight = getWeight(balanceSubTree(Op0N).getNode());
// Weight = calculateWeight(Op0N);
} else
Weight = getWeight(Op0N);
SDNode *Op1N = N->getOperand(1).getNode(); // Op1 may have been RAUWd
if (isOpcodeHandled(Op1N) && RootWeights[Op1N] == -1) {
Weight += getWeight(balanceSubTree(Op1N).getNode());
// Weight += calculateWeight(Op1N);
} else
Weight += getWeight(Op1N);
RootWeights[N] = Weight;
RootHeights[N] = std::max(getHeight(N->getOperand(0).getNode()),
getHeight(N->getOperand(1).getNode())) + 1;
DEBUG(dbgs() << "--> No need to balance root (Weight=" << Weight
<< " Height=" << RootHeights[N] << "): ");
DEBUG(N->dump());
return SDValue(N, 0);
}
DEBUG(dbgs() << "** Balancing root node: ");
DEBUG(N->dump());
unsigned NOpcode = N->getOpcode();
LeafPrioQueue Leaves(NOpcode);
SmallVector<SDValue, 4> Worklist;
Worklist.push_back(SDValue(N, 0));
// SHL nodes will be converted to MUL nodes
if (NOpcode == ISD::SHL)
NOpcode = ISD::MUL;
bool CanFactorize = false;
WeightedLeaf Mul1, Mul2;
unsigned MaxPowerOf2 = 0;
WeightedLeaf GA;
// Do not try to factor out a shift if there is already a shift at the tip of
// the tree.
bool HaveTopLevelShift = false;
if (TopLevel &&
((isOpcodeHandled(Op0.getNode()) && Op0.getOpcode() == ISD::SHL &&
Op0.getConstantOperandVal(1) < 4) ||
(isOpcodeHandled(Op1.getNode()) && Op1.getOpcode() == ISD::SHL &&
Op1.getConstantOperandVal(1) < 4)))
HaveTopLevelShift = true;
// Flatten the subtree into an ordered list of leaves; at the same time
// determine whether the tree is already balanced.
int InsertionOrder = 0;
SmallDenseMap<SDValue, int> NodeHeights;
bool Imbalanced = false;
int CurrentWeight = 0;
while (!Worklist.empty()) {
SDValue Child = Worklist.pop_back_val();
if (Child.getNode() != N && RootWeights.count(Child.getNode())) {
// CASE 1: Child is a root note
int Weight = RootWeights[Child.getNode()];
if (Weight == -1) {
Child = balanceSubTree(Child.getNode());
// calculateWeight(Child.getNode());
Weight = getWeight(Child.getNode());
} else if (Weight == -2) {
// Whoops, this node was RAUWd by one of the balanceSubTree calls we
// made. Our worklist isn't up to date anymore.
// Restart the whole process.
DEBUG(dbgs() << "--> Subtree was RAUWd. Restarting...\n");
return balanceSubTree(N, TopLevel);
}
NodeHeights[Child] = 1;
CurrentWeight += Weight;
unsigned PowerOf2;
if (TopLevel && !CanFactorize && !HaveTopLevelShift &&
(Child.getOpcode() == ISD::MUL || Child.getOpcode() == ISD::SHL) &&
Child.hasOneUse() && (PowerOf2 = getPowerOf2Factor(Child))) {
// Try to identify two factorizable MUL/SHL children greedily. Leave
// them out of the priority queue for now so we can deal with them
// after.
if (!Mul1.Value.getNode()) {
Mul1 = WeightedLeaf(Child, Weight, InsertionOrder++);
MaxPowerOf2 = PowerOf2;
} else {
Mul2 = WeightedLeaf(Child, Weight, InsertionOrder++);
MaxPowerOf2 = std::min(MaxPowerOf2, PowerOf2);
// Our addressing modes can only shift by a maximum of 3
if (MaxPowerOf2 > 3)
MaxPowerOf2 = 3;
CanFactorize = true;
}
} else
Leaves.push(WeightedLeaf(Child, Weight, InsertionOrder++));
} else if (!isOpcodeHandled(Child.getNode())) {
// CASE 2: Child is an unhandled kind of node (e.g. constant)
int Weight = getWeight(Child.getNode());
NodeHeights[Child] = getHeight(Child.getNode());
CurrentWeight += Weight;
if (isTargetConstant(Child) && !GA.Value.getNode())
GA = WeightedLeaf(Child, Weight, InsertionOrder++);
else
Leaves.push(WeightedLeaf(Child, Weight, InsertionOrder++));
} else {
// CASE 3: Child is a subtree of same opcode
// Visit children first, then flatten.
unsigned ChildOpcode = Child.getOpcode();
assert(ChildOpcode == NOpcode ||
(NOpcode == ISD::MUL && ChildOpcode == ISD::SHL));
// Convert SHL to MUL
SDValue Op1;
if (ChildOpcode == ISD::SHL)
Op1 = getMultiplierForSHL(Child.getNode());
else
Op1 = Child->getOperand(1);
if (!NodeHeights.count(Op1) || !NodeHeights.count(Child->getOperand(0))) {
assert(!NodeHeights.count(Child) && "Parent visited before children?");
// Visit children first, then re-visit this node
Worklist.push_back(Child);
Worklist.push_back(Op1);
Worklist.push_back(Child->getOperand(0));
} else {
// Back at this node after visiting the children
if (std::abs(NodeHeights[Op1] - NodeHeights[Child->getOperand(0)]) > 1)
Imbalanced = true;
NodeHeights[Child] = std::max(NodeHeights[Op1],
NodeHeights[Child->getOperand(0)]) + 1;
}
}
}
DEBUG(dbgs() << "--> Current height=" << NodeHeights[SDValue(N, 0)]
<< " weight=" << CurrentWeight << " imbalanced="
<< Imbalanced << "\n");
// Transform MUL(x, C * 2^Y) + SHL(z, Y) -> SHL(ADD(MUL(x, C), z), Y)
// This factors out a shift in order to match memw(a<<Y+b).
if (CanFactorize && (willShiftRightEliminate(Mul1.Value, MaxPowerOf2) ||
willShiftRightEliminate(Mul2.Value, MaxPowerOf2))) {
DEBUG(dbgs() << "--> Found common factor for two MUL children!\n");
int Weight = Mul1.Weight + Mul2.Weight;
int Height = std::max(NodeHeights[Mul1.Value], NodeHeights[Mul2.Value]) + 1;
SDValue Mul1Factored = factorOutPowerOf2(Mul1.Value, MaxPowerOf2);
SDValue Mul2Factored = factorOutPowerOf2(Mul2.Value, MaxPowerOf2);
SDValue Sum = CurDAG->getNode(ISD::ADD, SDLoc(N), Mul1.Value.getValueType(),
Mul1Factored, Mul2Factored);
SDValue Const = CurDAG->getConstant(MaxPowerOf2, SDLoc(N),
Mul1.Value.getValueType());
SDValue New = CurDAG->getNode(ISD::SHL, SDLoc(N), Mul1.Value.getValueType(),
Sum, Const);
NodeHeights[New] = Height;
Leaves.push(WeightedLeaf(New, Weight, Mul1.InsertionOrder));
} else if (Mul1.Value.getNode()) {
// We failed to factorize two MULs, so now the Muls are left outside the
// queue... add them back.
Leaves.push(Mul1);
if (Mul2.Value.getNode())
Leaves.push(Mul2);
CanFactorize = false;
}
// Combine GA + Constant -> GA+Offset, but only if GA is not used elsewhere
// and the root node itself is not used more than twice. This reduces the
// amount of additional constant extenders introduced by this optimization.
bool CombinedGA = false;
if (NOpcode == ISD::ADD && GA.Value.getNode() && Leaves.hasConst() &&
GA.Value.hasOneUse() && N->use_size() < 3) {
GlobalAddressSDNode *GANode =
cast<GlobalAddressSDNode>(GA.Value.getOperand(0));
ConstantSDNode *Offset = cast<ConstantSDNode>(Leaves.top().Value);
if (getUsesInFunction(GANode->getGlobal()) == 1 && Offset->hasOneUse() &&
getTargetLowering()->isOffsetFoldingLegal(GANode)) {
DEBUG(dbgs() << "--> Combining GA and offset (" << Offset->getSExtValue()
<< "): ");
DEBUG(GANode->dump());
SDValue NewTGA =
CurDAG->getTargetGlobalAddress(GANode->getGlobal(), SDLoc(GA.Value),
GANode->getValueType(0),
GANode->getOffset() + (uint64_t)Offset->getSExtValue());
GA.Value = CurDAG->getNode(GA.Value.getOpcode(), SDLoc(GA.Value),
GA.Value.getValueType(), NewTGA);
GA.Weight += Leaves.top().Weight;
NodeHeights[GA.Value] = getHeight(GA.Value.getNode());
CombinedGA = true;
Leaves.pop(); // Remove the offset constant from the queue
}
}
if ((RebalanceOnlyForOptimizations && !CanFactorize && !CombinedGA) ||
(RebalanceOnlyImbalancedTrees && !Imbalanced)) {
RootWeights[N] = CurrentWeight;
RootHeights[N] = NodeHeights[SDValue(N, 0)];
return SDValue(N, 0);
}
// Combine GA + SHL(x, C<=31) so we will match Rx=add(#u8,asl(Rx,#U5))
if (NOpcode == ISD::ADD && GA.Value.getNode()) {
WeightedLeaf SHL = Leaves.findSHL(31);
if (SHL.Value.getNode()) {
int Height = std::max(NodeHeights[GA.Value], NodeHeights[SHL.Value]) + 1;
GA.Value = CurDAG->getNode(ISD::ADD, SDLoc(GA.Value),
GA.Value.getValueType(),
GA.Value, SHL.Value);
GA.Weight = SHL.Weight; // Specifically ignore the GA weight here
NodeHeights[GA.Value] = Height;
}
}
if (GA.Value.getNode())
Leaves.push(GA);
// If this is the top level and we haven't factored out a shift, we should try
// to move a constant to the bottom to match addressing modes like memw(rX+C)
if (TopLevel && !CanFactorize && Leaves.hasConst()) {
DEBUG(dbgs() << "--> Pushing constant to tip of tree.");
Leaves.pushToBottom(Leaves.pop());
}
const DataLayout &DL = CurDAG->getDataLayout();
const TargetLowering &TLI = *getTargetLowering();
// Rebuild the tree using Huffman's algorithm
while (Leaves.size() > 1) {
WeightedLeaf L0 = Leaves.pop();
// See whether we can grab a MUL to form an add(Rx,mpyi(Ry,#u6)),
// otherwise just get the next leaf
WeightedLeaf L1 = Leaves.findMULbyConst();
if (!L1.Value.getNode())
L1 = Leaves.pop();
assert(L0.Weight <= L1.Weight && "Priority queue is broken!");
SDValue V0 = L0.Value;
int V0Weight = L0.Weight;
SDValue V1 = L1.Value;
int V1Weight = L1.Weight;
// Make sure that none of these nodes have been RAUW'd
if ((RootWeights.count(V0.getNode()) && RootWeights[V0.getNode()] == -2) ||
(RootWeights.count(V1.getNode()) && RootWeights[V1.getNode()] == -2)) {
DEBUG(dbgs() << "--> Subtree was RAUWd. Restarting...\n");
return balanceSubTree(N, TopLevel);
}
ConstantSDNode *V0C = dyn_cast<ConstantSDNode>(V0);
ConstantSDNode *V1C = dyn_cast<ConstantSDNode>(V1);
EVT VT = N->getValueType(0);
SDValue NewNode;
if (V0C && !V1C) {
std::swap(V0, V1);
std::swap(V0C, V1C);
}
// Calculate height of this node
assert(NodeHeights.count(V0) && NodeHeights.count(V1) &&
"Children must have been visited before re-combining them!");
int Height = std::max(NodeHeights[V0], NodeHeights[V1]) + 1;
// Rebuild this node (and restore SHL from MUL if needed)
if (V1C && NOpcode == ISD::MUL && V1C->getAPIntValue().isPowerOf2())
NewNode = CurDAG->getNode(
ISD::SHL, SDLoc(V0), VT, V0,
CurDAG->getConstant(
V1C->getAPIntValue().logBase2(), SDLoc(N),
TLI.getScalarShiftAmountTy(DL, V0.getValueType())));
else
NewNode = CurDAG->getNode(NOpcode, SDLoc(N), VT, V0, V1);
NodeHeights[NewNode] = Height;
int Weight = V0Weight + V1Weight;
Leaves.push(WeightedLeaf(NewNode, Weight, L0.InsertionOrder));
DEBUG(dbgs() << "--> Built new node (Weight=" << Weight << ",Height="
<< Height << "):\n");
DEBUG(NewNode.dump());
}
assert(Leaves.size() == 1);
SDValue NewRoot = Leaves.top().Value;
assert(NodeHeights.count(NewRoot));
int Height = NodeHeights[NewRoot];
// Restore SHL if we earlier converted it to a MUL
if (NewRoot.getOpcode() == ISD::MUL) {
ConstantSDNode *V1C = dyn_cast<ConstantSDNode>(NewRoot.getOperand(1));
if (V1C && V1C->getAPIntValue().isPowerOf2()) {
EVT VT = NewRoot.getValueType();
SDValue V0 = NewRoot.getOperand(0);
NewRoot = CurDAG->getNode(
ISD::SHL, SDLoc(NewRoot), VT, V0,
CurDAG->getConstant(
V1C->getAPIntValue().logBase2(), SDLoc(NewRoot),
TLI.getScalarShiftAmountTy(DL, V0.getValueType())));
}
}
if (N != NewRoot.getNode()) {
DEBUG(dbgs() << "--> Root is now: ");
DEBUG(NewRoot.dump());
// Replace all uses of old root by new root
CurDAG->ReplaceAllUsesWith(N, NewRoot.getNode());
// Mark that we have RAUW'd N
RootWeights[N] = -2;
} else {
DEBUG(dbgs() << "--> Root unchanged.\n");
}
RootWeights[NewRoot.getNode()] = Leaves.top().Weight;
RootHeights[NewRoot.getNode()] = Height;
return NewRoot;
}
void HexagonDAGToDAGISel::rebalanceAddressTrees() {
for (auto I = CurDAG->allnodes_begin(), E = CurDAG->allnodes_end(); I != E;) {
SDNode *N = &*I++;
if (N->getOpcode() != ISD::LOAD && N->getOpcode() != ISD::STORE)
continue;
SDValue BasePtr = cast<MemSDNode>(N)->getBasePtr();
if (BasePtr.getOpcode() != ISD::ADD)
continue;
// We've already processed this node
if (RootWeights.count(BasePtr.getNode()))
continue;
DEBUG(dbgs() << "** Rebalancing address calculation in node: ");
DEBUG(N->dump());
// FindRoots
SmallVector<SDNode *, 4> Worklist;
Worklist.push_back(BasePtr.getOperand(0).getNode());
Worklist.push_back(BasePtr.getOperand(1).getNode());
while (!Worklist.empty()) {
SDNode *N = Worklist.pop_back_val();
unsigned Opcode = N->getOpcode();
if (!isOpcodeHandled(N))
continue;
Worklist.push_back(N->getOperand(0).getNode());
Worklist.push_back(N->getOperand(1).getNode());
// Not a root if it has only one use and same opcode as its parent
if (N->hasOneUse() && Opcode == N->use_begin()->getOpcode())
continue;
// This root node has already been processed
if (RootWeights.count(N))
continue;
RootWeights[N] = -1;
}
// Balance node itself
RootWeights[BasePtr.getNode()] = -1;
SDValue NewBasePtr = balanceSubTree(BasePtr.getNode(), /*TopLevel=*/ true);
if (N->getOpcode() == ISD::LOAD)
N = CurDAG->UpdateNodeOperands(N, N->getOperand(0),
NewBasePtr, N->getOperand(2));
else
N = CurDAG->UpdateNodeOperands(N, N->getOperand(0), N->getOperand(1),
NewBasePtr, N->getOperand(3));
DEBUG(dbgs() << "--> Final node: ");
DEBUG(N->dump());
}
CurDAG->RemoveDeadNodes();
GAUsesInFunction.clear();
RootHeights.clear();
RootWeights.clear();
}
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