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llvm-project/llvm/lib/CodeGen/GlobalISel/LegalizerHelper.cpp
Roman Tereshin 6d26638c90 [GlobalISel][Legalizer] Widening the second src op of shifts bug fix 
The second source operand of G_SHL, G_ASHR, and G_LSHR must preserve its
value as a (small) unsigned integer, therefore its incorrect to widen it
in any way but by zero extending it.

G_SHL was using G_ANYEXT and G_ASHR - G_SEXT (which is correct for their
destination and first source operands, but not the "number of bits to
shift" operand).

Generally, shifts aren't as similar to regular binary operations as it
might seem, for instance, they aren't commutative nor associative and
the second source operand usually requires a special treatment.

Reviewers: bogner, javed.absar, aivchenk, rovka

Reviewed By: bogner

Subscribers: igorb, kristof.beyls, llvm-commits

Differential Revision: https://reviews.llvm.org/D46413

llvm-svn: 331926
2018-05-09 21:43:30 +00:00

1037 lines
36 KiB
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//===-- llvm/CodeGen/GlobalISel/LegalizerHelper.cpp -----------------------===//
//
// The LLVM Compiler Infrastructure
//
// This file is distributed under the University of Illinois Open Source
// License. See LICENSE.TXT for details.
//
//===----------------------------------------------------------------------===//
//
/// \file This file implements the LegalizerHelper class to legalize
/// individual instructions and the LegalizeMachineIR wrapper pass for the
/// primary legalization.
//
//===----------------------------------------------------------------------===//
#include "llvm/CodeGen/GlobalISel/LegalizerHelper.h"
#include "llvm/CodeGen/GlobalISel/CallLowering.h"
#include "llvm/CodeGen/GlobalISel/LegalizerInfo.h"
#include "llvm/CodeGen/MachineRegisterInfo.h"
#include "llvm/CodeGen/TargetLowering.h"
#include "llvm/CodeGen/TargetSubtargetInfo.h"
#include "llvm/Support/Debug.h"
#include "llvm/Support/raw_ostream.h"
#define DEBUG_TYPE "legalizer"
using namespace llvm;
using namespace LegalizeActions;
LegalizerHelper::LegalizerHelper(MachineFunction &MF)
: MRI(MF.getRegInfo()), LI(*MF.getSubtarget().getLegalizerInfo()) {
MIRBuilder.setMF(MF);
}
LegalizerHelper::LegalizeResult
LegalizerHelper::legalizeInstrStep(MachineInstr &MI) {
DEBUG(dbgs() << "Legalizing: "; MI.print(dbgs()));
auto Step = LI.getAction(MI, MRI);
switch (Step.Action) {
case Legal:
DEBUG(dbgs() << ".. Already legal\n");
return AlreadyLegal;
case Libcall:
DEBUG(dbgs() << ".. Convert to libcall\n");
return libcall(MI);
case NarrowScalar:
DEBUG(dbgs() << ".. Narrow scalar\n");
return narrowScalar(MI, Step.TypeIdx, Step.NewType);
case WidenScalar:
DEBUG(dbgs() << ".. Widen scalar\n");
return widenScalar(MI, Step.TypeIdx, Step.NewType);
case Lower:
DEBUG(dbgs() << ".. Lower\n");
return lower(MI, Step.TypeIdx, Step.NewType);
case FewerElements:
DEBUG(dbgs() << ".. Reduce number of elements\n");
return fewerElementsVector(MI, Step.TypeIdx, Step.NewType);
case Custom:
DEBUG(dbgs() << ".. Custom legalization\n");
return LI.legalizeCustom(MI, MRI, MIRBuilder) ? Legalized
: UnableToLegalize;
default:
DEBUG(dbgs() << ".. Unable to legalize\n");
return UnableToLegalize;
}
}
void LegalizerHelper::extractParts(unsigned Reg, LLT Ty, int NumParts,
SmallVectorImpl<unsigned> &VRegs) {
for (int i = 0; i < NumParts; ++i)
VRegs.push_back(MRI.createGenericVirtualRegister(Ty));
MIRBuilder.buildUnmerge(VRegs, Reg);
}
static RTLIB::Libcall getRTLibDesc(unsigned Opcode, unsigned Size) {
switch (Opcode) {
case TargetOpcode::G_SDIV:
assert(Size == 32 && "Unsupported size");
return RTLIB::SDIV_I32;
case TargetOpcode::G_UDIV:
assert(Size == 32 && "Unsupported size");
return RTLIB::UDIV_I32;
case TargetOpcode::G_SREM:
assert(Size == 32 && "Unsupported size");
return RTLIB::SREM_I32;
case TargetOpcode::G_UREM:
assert(Size == 32 && "Unsupported size");
return RTLIB::UREM_I32;
case TargetOpcode::G_FADD:
assert((Size == 32 || Size == 64) && "Unsupported size");
return Size == 64 ? RTLIB::ADD_F64 : RTLIB::ADD_F32;
case TargetOpcode::G_FSUB:
assert((Size == 32 || Size == 64) && "Unsupported size");
return Size == 64 ? RTLIB::SUB_F64 : RTLIB::SUB_F32;
case TargetOpcode::G_FMUL:
assert((Size == 32 || Size == 64) && "Unsupported size");
return Size == 64 ? RTLIB::MUL_F64 : RTLIB::MUL_F32;
case TargetOpcode::G_FDIV:
assert((Size == 32 || Size == 64) && "Unsupported size");
return Size == 64 ? RTLIB::DIV_F64 : RTLIB::DIV_F32;
case TargetOpcode::G_FREM:
return Size == 64 ? RTLIB::REM_F64 : RTLIB::REM_F32;
case TargetOpcode::G_FPOW:
return Size == 64 ? RTLIB::POW_F64 : RTLIB::POW_F32;
case TargetOpcode::G_FMA:
assert((Size == 32 || Size == 64) && "Unsupported size");
return Size == 64 ? RTLIB::FMA_F64 : RTLIB::FMA_F32;
}
llvm_unreachable("Unknown libcall function");
}
LegalizerHelper::LegalizeResult
llvm::createLibcall(MachineIRBuilder &MIRBuilder, RTLIB::Libcall Libcall,
const CallLowering::ArgInfo &Result,
ArrayRef<CallLowering::ArgInfo> Args) {
auto &CLI = *MIRBuilder.getMF().getSubtarget().getCallLowering();
auto &TLI = *MIRBuilder.getMF().getSubtarget().getTargetLowering();
const char *Name = TLI.getLibcallName(Libcall);
MIRBuilder.getMF().getFrameInfo().setHasCalls(true);
if (!CLI.lowerCall(MIRBuilder, TLI.getLibcallCallingConv(Libcall),
MachineOperand::CreateES(Name), Result, Args))
return LegalizerHelper::UnableToLegalize;
return LegalizerHelper::Legalized;
}
// Useful for libcalls where all operands have the same type.
static LegalizerHelper::LegalizeResult
simpleLibcall(MachineInstr &MI, MachineIRBuilder &MIRBuilder, unsigned Size,
Type *OpType) {
auto Libcall = getRTLibDesc(MI.getOpcode(), Size);
SmallVector<CallLowering::ArgInfo, 3> Args;
for (unsigned i = 1; i < MI.getNumOperands(); i++)
Args.push_back({MI.getOperand(i).getReg(), OpType});
return createLibcall(MIRBuilder, Libcall, {MI.getOperand(0).getReg(), OpType},
Args);
}
static RTLIB::Libcall getConvRTLibDesc(unsigned Opcode, Type *ToType,
Type *FromType) {
auto ToMVT = MVT::getVT(ToType);
auto FromMVT = MVT::getVT(FromType);
switch (Opcode) {
case TargetOpcode::G_FPEXT:
return RTLIB::getFPEXT(FromMVT, ToMVT);
case TargetOpcode::G_FPTRUNC:
return RTLIB::getFPROUND(FromMVT, ToMVT);
case TargetOpcode::G_FPTOSI:
return RTLIB::getFPTOSINT(FromMVT, ToMVT);
case TargetOpcode::G_FPTOUI:
return RTLIB::getFPTOUINT(FromMVT, ToMVT);
case TargetOpcode::G_SITOFP:
return RTLIB::getSINTTOFP(FromMVT, ToMVT);
case TargetOpcode::G_UITOFP:
return RTLIB::getUINTTOFP(FromMVT, ToMVT);
}
llvm_unreachable("Unsupported libcall function");
}
static LegalizerHelper::LegalizeResult
conversionLibcall(MachineInstr &MI, MachineIRBuilder &MIRBuilder, Type *ToType,
Type *FromType) {
RTLIB::Libcall Libcall = getConvRTLibDesc(MI.getOpcode(), ToType, FromType);
return createLibcall(MIRBuilder, Libcall, {MI.getOperand(0).getReg(), ToType},
{{MI.getOperand(1).getReg(), FromType}});
}
LegalizerHelper::LegalizeResult
LegalizerHelper::libcall(MachineInstr &MI) {
LLT LLTy = MRI.getType(MI.getOperand(0).getReg());
unsigned Size = LLTy.getSizeInBits();
auto &Ctx = MIRBuilder.getMF().getFunction().getContext();
MIRBuilder.setInstr(MI);
switch (MI.getOpcode()) {
default:
return UnableToLegalize;
case TargetOpcode::G_SDIV:
case TargetOpcode::G_UDIV:
case TargetOpcode::G_SREM:
case TargetOpcode::G_UREM: {
Type *HLTy = Type::getInt32Ty(Ctx);
auto Status = simpleLibcall(MI, MIRBuilder, Size, HLTy);
if (Status != Legalized)
return Status;
break;
}
case TargetOpcode::G_FADD:
case TargetOpcode::G_FSUB:
case TargetOpcode::G_FMUL:
case TargetOpcode::G_FDIV:
case TargetOpcode::G_FMA:
case TargetOpcode::G_FPOW:
case TargetOpcode::G_FREM: {
Type *HLTy = Size == 64 ? Type::getDoubleTy(Ctx) : Type::getFloatTy(Ctx);
auto Status = simpleLibcall(MI, MIRBuilder, Size, HLTy);
if (Status != Legalized)
return Status;
break;
}
case TargetOpcode::G_FPEXT: {
// FIXME: Support other floating point types (half, fp128 etc)
unsigned FromSize = MRI.getType(MI.getOperand(1).getReg()).getSizeInBits();
unsigned ToSize = MRI.getType(MI.getOperand(0).getReg()).getSizeInBits();
if (ToSize != 64 || FromSize != 32)
return UnableToLegalize;
LegalizeResult Status = conversionLibcall(
MI, MIRBuilder, Type::getDoubleTy(Ctx), Type::getFloatTy(Ctx));
if (Status != Legalized)
return Status;
break;
}
case TargetOpcode::G_FPTRUNC: {
// FIXME: Support other floating point types (half, fp128 etc)
unsigned FromSize = MRI.getType(MI.getOperand(1).getReg()).getSizeInBits();
unsigned ToSize = MRI.getType(MI.getOperand(0).getReg()).getSizeInBits();
if (ToSize != 32 || FromSize != 64)
return UnableToLegalize;
LegalizeResult Status = conversionLibcall(
MI, MIRBuilder, Type::getFloatTy(Ctx), Type::getDoubleTy(Ctx));
if (Status != Legalized)
return Status;
break;
}
case TargetOpcode::G_FPTOSI:
case TargetOpcode::G_FPTOUI: {
// FIXME: Support other types
unsigned FromSize = MRI.getType(MI.getOperand(1).getReg()).getSizeInBits();
unsigned ToSize = MRI.getType(MI.getOperand(0).getReg()).getSizeInBits();
if (ToSize != 32 || (FromSize != 32 && FromSize != 64))
return UnableToLegalize;
LegalizeResult Status = conversionLibcall(
MI, MIRBuilder, Type::getInt32Ty(Ctx),
FromSize == 64 ? Type::getDoubleTy(Ctx) : Type::getFloatTy(Ctx));
if (Status != Legalized)
return Status;
break;
}
case TargetOpcode::G_SITOFP:
case TargetOpcode::G_UITOFP: {
// FIXME: Support other types
unsigned FromSize = MRI.getType(MI.getOperand(1).getReg()).getSizeInBits();
unsigned ToSize = MRI.getType(MI.getOperand(0).getReg()).getSizeInBits();
if (FromSize != 32 || (ToSize != 32 && ToSize != 64))
return UnableToLegalize;
LegalizeResult Status = conversionLibcall(
MI, MIRBuilder,
ToSize == 64 ? Type::getDoubleTy(Ctx) : Type::getFloatTy(Ctx),
Type::getInt32Ty(Ctx));
if (Status != Legalized)
return Status;
break;
}
}
MI.eraseFromParent();
return Legalized;
}
LegalizerHelper::LegalizeResult LegalizerHelper::narrowScalar(MachineInstr &MI,
unsigned TypeIdx,
LLT NarrowTy) {
// FIXME: Don't know how to handle secondary types yet.
if (TypeIdx != 0 && MI.getOpcode() != TargetOpcode::G_EXTRACT)
return UnableToLegalize;
MIRBuilder.setInstr(MI);
uint64_t SizeOp0 = MRI.getType(MI.getOperand(0).getReg()).getSizeInBits();
uint64_t NarrowSize = NarrowTy.getSizeInBits();
switch (MI.getOpcode()) {
default:
return UnableToLegalize;
case TargetOpcode::G_IMPLICIT_DEF: {
// FIXME: add support for when SizeOp0 isn't an exact multiple of
// NarrowSize.
if (SizeOp0 % NarrowSize != 0)
return UnableToLegalize;
int NumParts = SizeOp0 / NarrowSize;
SmallVector<unsigned, 2> DstRegs;
for (int i = 0; i < NumParts; ++i)
DstRegs.push_back(
MIRBuilder.buildUndef(NarrowTy)->getOperand(0).getReg());
MIRBuilder.buildMerge(MI.getOperand(0).getReg(), DstRegs);
MI.eraseFromParent();
return Legalized;
}
case TargetOpcode::G_ADD: {
// FIXME: add support for when SizeOp0 isn't an exact multiple of
// NarrowSize.
if (SizeOp0 % NarrowSize != 0)
return UnableToLegalize;
// Expand in terms of carry-setting/consuming G_ADDE instructions.
int NumParts = SizeOp0 / NarrowTy.getSizeInBits();
SmallVector<unsigned, 2> Src1Regs, Src2Regs, DstRegs;
extractParts(MI.getOperand(1).getReg(), NarrowTy, NumParts, Src1Regs);
extractParts(MI.getOperand(2).getReg(), NarrowTy, NumParts, Src2Regs);
unsigned CarryIn = MRI.createGenericVirtualRegister(LLT::scalar(1));
MIRBuilder.buildConstant(CarryIn, 0);
for (int i = 0; i < NumParts; ++i) {
unsigned DstReg = MRI.createGenericVirtualRegister(NarrowTy);
unsigned CarryOut = MRI.createGenericVirtualRegister(LLT::scalar(1));
MIRBuilder.buildUAdde(DstReg, CarryOut, Src1Regs[i],
Src2Regs[i], CarryIn);
DstRegs.push_back(DstReg);
CarryIn = CarryOut;
}
unsigned DstReg = MI.getOperand(0).getReg();
MIRBuilder.buildMerge(DstReg, DstRegs);
MI.eraseFromParent();
return Legalized;
}
case TargetOpcode::G_EXTRACT: {
if (TypeIdx != 1)
return UnableToLegalize;
int64_t SizeOp1 = MRI.getType(MI.getOperand(1).getReg()).getSizeInBits();
// FIXME: add support for when SizeOp1 isn't an exact multiple of
// NarrowSize.
if (SizeOp1 % NarrowSize != 0)
return UnableToLegalize;
int NumParts = SizeOp1 / NarrowSize;
SmallVector<unsigned, 2> SrcRegs, DstRegs;
SmallVector<uint64_t, 2> Indexes;
extractParts(MI.getOperand(1).getReg(), NarrowTy, NumParts, SrcRegs);
unsigned OpReg = MI.getOperand(0).getReg();
uint64_t OpStart = MI.getOperand(2).getImm();
uint64_t OpSize = MRI.getType(OpReg).getSizeInBits();
for (int i = 0; i < NumParts; ++i) {
unsigned SrcStart = i * NarrowSize;
if (SrcStart + NarrowSize <= OpStart || SrcStart >= OpStart + OpSize) {
// No part of the extract uses this subregister, ignore it.
continue;
} else if (SrcStart == OpStart && NarrowTy == MRI.getType(OpReg)) {
// The entire subregister is extracted, forward the value.
DstRegs.push_back(SrcRegs[i]);
continue;
}
// OpSegStart is where this destination segment would start in OpReg if it
// extended infinitely in both directions.
int64_t ExtractOffset;
uint64_t SegSize;
if (OpStart < SrcStart) {
ExtractOffset = 0;
SegSize = std::min(NarrowSize, OpStart + OpSize - SrcStart);
} else {
ExtractOffset = OpStart - SrcStart;
SegSize = std::min(SrcStart + NarrowSize - OpStart, OpSize);
}
unsigned SegReg = SrcRegs[i];
if (ExtractOffset != 0 || SegSize != NarrowSize) {
// A genuine extract is needed.
SegReg = MRI.createGenericVirtualRegister(LLT::scalar(SegSize));
MIRBuilder.buildExtract(SegReg, SrcRegs[i], ExtractOffset);
}
DstRegs.push_back(SegReg);
}
MIRBuilder.buildMerge(MI.getOperand(0).getReg(), DstRegs);
MI.eraseFromParent();
return Legalized;
}
case TargetOpcode::G_INSERT: {
// FIXME: add support for when SizeOp0 isn't an exact multiple of
// NarrowSize.
if (SizeOp0 % NarrowSize != 0)
return UnableToLegalize;
int NumParts = SizeOp0 / NarrowSize;
SmallVector<unsigned, 2> SrcRegs, DstRegs;
SmallVector<uint64_t, 2> Indexes;
extractParts(MI.getOperand(1).getReg(), NarrowTy, NumParts, SrcRegs);
unsigned OpReg = MI.getOperand(2).getReg();
uint64_t OpStart = MI.getOperand(3).getImm();
uint64_t OpSize = MRI.getType(OpReg).getSizeInBits();
for (int i = 0; i < NumParts; ++i) {
unsigned DstStart = i * NarrowSize;
if (DstStart + NarrowSize <= OpStart || DstStart >= OpStart + OpSize) {
// No part of the insert affects this subregister, forward the original.
DstRegs.push_back(SrcRegs[i]);
continue;
} else if (DstStart == OpStart && NarrowTy == MRI.getType(OpReg)) {
// The entire subregister is defined by this insert, forward the new
// value.
DstRegs.push_back(OpReg);
continue;
}
// OpSegStart is where this destination segment would start in OpReg if it
// extended infinitely in both directions.
int64_t ExtractOffset, InsertOffset;
uint64_t SegSize;
if (OpStart < DstStart) {
InsertOffset = 0;
ExtractOffset = DstStart - OpStart;
SegSize = std::min(NarrowSize, OpStart + OpSize - DstStart);
} else {
InsertOffset = OpStart - DstStart;
ExtractOffset = 0;
SegSize =
std::min(NarrowSize - InsertOffset, OpStart + OpSize - DstStart);
}
unsigned SegReg = OpReg;
if (ExtractOffset != 0 || SegSize != OpSize) {
// A genuine extract is needed.
SegReg = MRI.createGenericVirtualRegister(LLT::scalar(SegSize));
MIRBuilder.buildExtract(SegReg, OpReg, ExtractOffset);
}
unsigned DstReg = MRI.createGenericVirtualRegister(NarrowTy);
MIRBuilder.buildInsert(DstReg, SrcRegs[i], SegReg, InsertOffset);
DstRegs.push_back(DstReg);
}
assert(DstRegs.size() == (unsigned)NumParts && "not all parts covered");
MIRBuilder.buildMerge(MI.getOperand(0).getReg(), DstRegs);
MI.eraseFromParent();
return Legalized;
}
case TargetOpcode::G_LOAD: {
// FIXME: add support for when SizeOp0 isn't an exact multiple of
// NarrowSize.
if (SizeOp0 % NarrowSize != 0)
return UnableToLegalize;
const auto &MMO = **MI.memoperands_begin();
// This implementation doesn't work for atomics. Give up instead of doing
// something invalid.
if (MMO.getOrdering() != AtomicOrdering::NotAtomic ||
MMO.getFailureOrdering() != AtomicOrdering::NotAtomic)
return UnableToLegalize;
int NumParts = SizeOp0 / NarrowSize;
LLT OffsetTy = LLT::scalar(
MRI.getType(MI.getOperand(1).getReg()).getScalarSizeInBits());
SmallVector<unsigned, 2> DstRegs;
for (int i = 0; i < NumParts; ++i) {
unsigned DstReg = MRI.createGenericVirtualRegister(NarrowTy);
unsigned SrcReg = 0;
unsigned Adjustment = i * NarrowSize / 8;
MachineMemOperand *SplitMMO = MIRBuilder.getMF().getMachineMemOperand(
MMO.getPointerInfo().getWithOffset(Adjustment), MMO.getFlags(),
NarrowSize / 8, i == 0 ? MMO.getAlignment() : NarrowSize / 8,
MMO.getAAInfo(), MMO.getRanges(), MMO.getSyncScopeID(),
MMO.getOrdering(), MMO.getFailureOrdering());
MIRBuilder.materializeGEP(SrcReg, MI.getOperand(1).getReg(), OffsetTy,
Adjustment);
MIRBuilder.buildLoad(DstReg, SrcReg, *SplitMMO);
DstRegs.push_back(DstReg);
}
unsigned DstReg = MI.getOperand(0).getReg();
MIRBuilder.buildMerge(DstReg, DstRegs);
MI.eraseFromParent();
return Legalized;
}
case TargetOpcode::G_STORE: {
// FIXME: add support for when SizeOp0 isn't an exact multiple of
// NarrowSize.
if (SizeOp0 % NarrowSize != 0)
return UnableToLegalize;
const auto &MMO = **MI.memoperands_begin();
// This implementation doesn't work for atomics. Give up instead of doing
// something invalid.
if (MMO.getOrdering() != AtomicOrdering::NotAtomic ||
MMO.getFailureOrdering() != AtomicOrdering::NotAtomic)
return UnableToLegalize;
int NumParts = SizeOp0 / NarrowSize;
LLT OffsetTy = LLT::scalar(
MRI.getType(MI.getOperand(1).getReg()).getScalarSizeInBits());
SmallVector<unsigned, 2> SrcRegs;
extractParts(MI.getOperand(0).getReg(), NarrowTy, NumParts, SrcRegs);
for (int i = 0; i < NumParts; ++i) {
unsigned DstReg = 0;
unsigned Adjustment = i * NarrowSize / 8;
MachineMemOperand *SplitMMO = MIRBuilder.getMF().getMachineMemOperand(
MMO.getPointerInfo().getWithOffset(Adjustment), MMO.getFlags(),
NarrowSize / 8, i == 0 ? MMO.getAlignment() : NarrowSize / 8,
MMO.getAAInfo(), MMO.getRanges(), MMO.getSyncScopeID(),
MMO.getOrdering(), MMO.getFailureOrdering());
MIRBuilder.materializeGEP(DstReg, MI.getOperand(1).getReg(), OffsetTy,
Adjustment);
MIRBuilder.buildStore(SrcRegs[i], DstReg, *SplitMMO);
}
MI.eraseFromParent();
return Legalized;
}
case TargetOpcode::G_CONSTANT: {
// FIXME: add support for when SizeOp0 isn't an exact multiple of
// NarrowSize.
if (SizeOp0 % NarrowSize != 0)
return UnableToLegalize;
int NumParts = SizeOp0 / NarrowSize;
const APInt &Cst = MI.getOperand(1).getCImm()->getValue();
LLVMContext &Ctx = MIRBuilder.getMF().getFunction().getContext();
SmallVector<unsigned, 2> DstRegs;
for (int i = 0; i < NumParts; ++i) {
unsigned DstReg = MRI.createGenericVirtualRegister(NarrowTy);
ConstantInt *CI =
ConstantInt::get(Ctx, Cst.lshr(NarrowSize * i).trunc(NarrowSize));
MIRBuilder.buildConstant(DstReg, *CI);
DstRegs.push_back(DstReg);
}
unsigned DstReg = MI.getOperand(0).getReg();
MIRBuilder.buildMerge(DstReg, DstRegs);
MI.eraseFromParent();
return Legalized;
}
case TargetOpcode::G_OR: {
// Legalize bitwise operation:
// A = BinOp<Ty> B, C
// into:
// B1, ..., BN = G_UNMERGE_VALUES B
// C1, ..., CN = G_UNMERGE_VALUES C
// A1 = BinOp<Ty/N> B1, C2
// ...
// AN = BinOp<Ty/N> BN, CN
// A = G_MERGE_VALUES A1, ..., AN
// FIXME: add support for when SizeOp0 isn't an exact multiple of
// NarrowSize.
if (SizeOp0 % NarrowSize != 0)
return UnableToLegalize;
int NumParts = SizeOp0 / NarrowSize;
// List the registers where the destination will be scattered.
SmallVector<unsigned, 2> DstRegs;
// List the registers where the first argument will be split.
SmallVector<unsigned, 2> SrcsReg1;
// List the registers where the second argument will be split.
SmallVector<unsigned, 2> SrcsReg2;
// Create all the temporary registers.
for (int i = 0; i < NumParts; ++i) {
unsigned DstReg = MRI.createGenericVirtualRegister(NarrowTy);
unsigned SrcReg1 = MRI.createGenericVirtualRegister(NarrowTy);
unsigned SrcReg2 = MRI.createGenericVirtualRegister(NarrowTy);
DstRegs.push_back(DstReg);
SrcsReg1.push_back(SrcReg1);
SrcsReg2.push_back(SrcReg2);
}
// Explode the big arguments into smaller chunks.
MIRBuilder.buildUnmerge(SrcsReg1, MI.getOperand(1).getReg());
MIRBuilder.buildUnmerge(SrcsReg2, MI.getOperand(2).getReg());
// Do the operation on each small part.
for (int i = 0; i < NumParts; ++i)
MIRBuilder.buildOr(DstRegs[i], SrcsReg1[i], SrcsReg2[i]);
// Gather the destination registers into the final destination.
unsigned DstReg = MI.getOperand(0).getReg();
MIRBuilder.buildMerge(DstReg, DstRegs);
MI.eraseFromParent();
return Legalized;
}
}
}
void LegalizerHelper::widenScalarSrc(MachineInstr &MI, LLT WideTy,
unsigned OpIdx, unsigned ExtOpcode) {
MachineOperand &MO = MI.getOperand(OpIdx);
auto ExtB = MIRBuilder.buildInstr(ExtOpcode, WideTy, MO.getReg());
MO.setReg(ExtB->getOperand(0).getReg());
}
void LegalizerHelper::widenScalarDst(MachineInstr &MI, LLT WideTy,
unsigned OpIdx, unsigned TruncOpcode) {
MachineOperand &MO = MI.getOperand(OpIdx);
unsigned DstExt = MRI.createGenericVirtualRegister(WideTy);
MIRBuilder.setInsertPt(MIRBuilder.getMBB(), ++MIRBuilder.getInsertPt());
MIRBuilder.buildInstr(TruncOpcode, MO.getReg(), DstExt);
MO.setReg(DstExt);
}
LegalizerHelper::LegalizeResult
LegalizerHelper::widenScalar(MachineInstr &MI, unsigned TypeIdx, LLT WideTy) {
MIRBuilder.setInstr(MI);
switch (MI.getOpcode()) {
default:
return UnableToLegalize;
case TargetOpcode::G_ADD:
case TargetOpcode::G_AND:
case TargetOpcode::G_MUL:
case TargetOpcode::G_OR:
case TargetOpcode::G_XOR:
case TargetOpcode::G_SUB:
// Perform operation at larger width (any extension is fine here, high bits
// don't affect the result) and then truncate the result back to the
// original type.
widenScalarSrc(MI, WideTy, 1, TargetOpcode::G_ANYEXT);
widenScalarSrc(MI, WideTy, 2, TargetOpcode::G_ANYEXT);
widenScalarDst(MI, WideTy);
MIRBuilder.recordInsertion(&MI);
return Legalized;
case TargetOpcode::G_SHL:
widenScalarSrc(MI, WideTy, 1, TargetOpcode::G_ANYEXT);
// The "number of bits to shift" operand must preserve its value as an
// unsigned integer:
widenScalarSrc(MI, WideTy, 2, TargetOpcode::G_ZEXT);
widenScalarDst(MI, WideTy);
MIRBuilder.recordInsertion(&MI);
return Legalized;
case TargetOpcode::G_SDIV:
case TargetOpcode::G_SREM:
widenScalarSrc(MI, WideTy, 1, TargetOpcode::G_SEXT);
widenScalarSrc(MI, WideTy, 2, TargetOpcode::G_SEXT);
widenScalarDst(MI, WideTy);
MIRBuilder.recordInsertion(&MI);
return Legalized;
case TargetOpcode::G_ASHR:
widenScalarSrc(MI, WideTy, 1, TargetOpcode::G_SEXT);
// The "number of bits to shift" operand must preserve its value as an
// unsigned integer:
widenScalarSrc(MI, WideTy, 2, TargetOpcode::G_ZEXT);
widenScalarDst(MI, WideTy);
MIRBuilder.recordInsertion(&MI);
return Legalized;
case TargetOpcode::G_UDIV:
case TargetOpcode::G_UREM:
case TargetOpcode::G_LSHR:
widenScalarSrc(MI, WideTy, 1, TargetOpcode::G_ZEXT);
widenScalarSrc(MI, WideTy, 2, TargetOpcode::G_ZEXT);
widenScalarDst(MI, WideTy);
MIRBuilder.recordInsertion(&MI);
return Legalized;
case TargetOpcode::G_SELECT:
if (TypeIdx != 0)
return UnableToLegalize;
// Perform operation at larger width (any extension is fine here, high bits
// don't affect the result) and then truncate the result back to the
// original type.
widenScalarSrc(MI, WideTy, 2, TargetOpcode::G_ANYEXT);
widenScalarSrc(MI, WideTy, 3, TargetOpcode::G_ANYEXT);
widenScalarDst(MI, WideTy);
MIRBuilder.recordInsertion(&MI);
return Legalized;
case TargetOpcode::G_FPTOSI:
case TargetOpcode::G_FPTOUI:
if (TypeIdx != 0)
return UnableToLegalize;
widenScalarDst(MI, WideTy);
MIRBuilder.recordInsertion(&MI);
return Legalized;
case TargetOpcode::G_SITOFP:
if (TypeIdx != 1)
return UnableToLegalize;
widenScalarSrc(MI, WideTy, 1, TargetOpcode::G_SEXT);
MIRBuilder.recordInsertion(&MI);
return Legalized;
case TargetOpcode::G_UITOFP:
if (TypeIdx != 1)
return UnableToLegalize;
widenScalarSrc(MI, WideTy, 1, TargetOpcode::G_ZEXT);
MIRBuilder.recordInsertion(&MI);
return Legalized;
case TargetOpcode::G_INSERT:
if (TypeIdx != 0)
return UnableToLegalize;
widenScalarSrc(MI, WideTy, 1, TargetOpcode::G_ANYEXT);
widenScalarDst(MI, WideTy);
MIRBuilder.recordInsertion(&MI);
return Legalized;
case TargetOpcode::G_LOAD:
// For some types like i24, we might try to widen to i32. To properly handle
// this we should be using a dedicated extending load, until then avoid
// trying to legalize.
if (alignTo(MRI.getType(MI.getOperand(0).getReg()).getSizeInBits(), 8) !=
WideTy.getSizeInBits())
return UnableToLegalize;
LLVM_FALLTHROUGH;
case TargetOpcode::G_SEXTLOAD:
case TargetOpcode::G_ZEXTLOAD:
widenScalarDst(MI, WideTy);
MIRBuilder.recordInsertion(&MI);
return Legalized;
case TargetOpcode::G_STORE: {
if (MRI.getType(MI.getOperand(0).getReg()) != LLT::scalar(1) ||
WideTy != LLT::scalar(8))
return UnableToLegalize;
const auto &TLI = *MIRBuilder.getMF().getSubtarget().getTargetLowering();
switch (TLI.getBooleanContents(false, false)) {
case TargetLoweringBase::ZeroOrNegativeOneBooleanContent:
widenScalarSrc(MI, WideTy, 0, TargetOpcode::G_SEXT);
break;
case TargetLoweringBase::ZeroOrOneBooleanContent:
widenScalarSrc(MI, WideTy, 0, TargetOpcode::G_ZEXT);
break;
default:
widenScalarSrc(MI, WideTy, 0, TargetOpcode::G_ANYEXT);
}
MIRBuilder.recordInsertion(&MI);
return Legalized;
}
case TargetOpcode::G_CONSTANT: {
MachineOperand &SrcMO = MI.getOperand(1);
LLVMContext &Ctx = MIRBuilder.getMF().getFunction().getContext();
const APInt &Val = SrcMO.getCImm()->getValue().sext(WideTy.getSizeInBits());
SrcMO.setCImm(ConstantInt::get(Ctx, Val));
widenScalarDst(MI, WideTy);
MIRBuilder.recordInsertion(&MI);
return Legalized;
}
case TargetOpcode::G_FCONSTANT: {
MachineOperand &SrcMO = MI.getOperand(1);
LLVMContext &Ctx = MIRBuilder.getMF().getFunction().getContext();
APFloat Val = SrcMO.getFPImm()->getValueAPF();
bool LosesInfo;
switch (WideTy.getSizeInBits()) {
case 32:
Val.convert(APFloat::IEEEsingle(), APFloat::rmTowardZero, &LosesInfo);
break;
case 64:
Val.convert(APFloat::IEEEdouble(), APFloat::rmTowardZero, &LosesInfo);
break;
default:
llvm_unreachable("Unhandled fp widen type");
}
SrcMO.setFPImm(ConstantFP::get(Ctx, Val));
widenScalarDst(MI, WideTy, 0, TargetOpcode::G_FPTRUNC);
MIRBuilder.recordInsertion(&MI);
return Legalized;
}
case TargetOpcode::G_BRCOND:
widenScalarSrc(MI, WideTy, 0, TargetOpcode::G_ANYEXT);
MIRBuilder.recordInsertion(&MI);
return Legalized;
case TargetOpcode::G_FCMP:
if (TypeIdx == 0)
widenScalarDst(MI, WideTy);
else {
widenScalarSrc(MI, WideTy, 2, TargetOpcode::G_FPEXT);
widenScalarSrc(MI, WideTy, 3, TargetOpcode::G_FPEXT);
}
MIRBuilder.recordInsertion(&MI);
return Legalized;
case TargetOpcode::G_ICMP:
if (TypeIdx == 0)
widenScalarDst(MI, WideTy);
else {
unsigned ExtOpcode = CmpInst::isSigned(static_cast<CmpInst::Predicate>(
MI.getOperand(1).getPredicate()))
? TargetOpcode::G_SEXT
: TargetOpcode::G_ZEXT;
widenScalarSrc(MI, WideTy, 2, ExtOpcode);
widenScalarSrc(MI, WideTy, 3, ExtOpcode);
}
MIRBuilder.recordInsertion(&MI);
return Legalized;
case TargetOpcode::G_GEP:
assert(TypeIdx == 1 && "unable to legalize pointer of GEP");
widenScalarSrc(MI, WideTy, 2, TargetOpcode::G_SEXT);
MIRBuilder.recordInsertion(&MI);
return Legalized;
case TargetOpcode::G_PHI: {
assert(TypeIdx == 0 && "Expecting only Idx 0");
for (unsigned I = 1; I < MI.getNumOperands(); I += 2) {
MachineBasicBlock &OpMBB = *MI.getOperand(I + 1).getMBB();
MIRBuilder.setInsertPt(OpMBB, OpMBB.getFirstTerminator());
widenScalarSrc(MI, WideTy, I, TargetOpcode::G_ANYEXT);
}
MachineBasicBlock &MBB = *MI.getParent();
MIRBuilder.setInsertPt(MBB, --MBB.getFirstNonPHI());
widenScalarDst(MI, WideTy);
MIRBuilder.recordInsertion(&MI);
return Legalized;
}
}
}
LegalizerHelper::LegalizeResult
LegalizerHelper::lower(MachineInstr &MI, unsigned TypeIdx, LLT Ty) {
using namespace TargetOpcode;
MIRBuilder.setInstr(MI);
switch(MI.getOpcode()) {
default:
return UnableToLegalize;
case TargetOpcode::G_SREM:
case TargetOpcode::G_UREM: {
unsigned QuotReg = MRI.createGenericVirtualRegister(Ty);
MIRBuilder.buildInstr(MI.getOpcode() == G_SREM ? G_SDIV : G_UDIV)
.addDef(QuotReg)
.addUse(MI.getOperand(1).getReg())
.addUse(MI.getOperand(2).getReg());
unsigned ProdReg = MRI.createGenericVirtualRegister(Ty);
MIRBuilder.buildMul(ProdReg, QuotReg, MI.getOperand(2).getReg());
MIRBuilder.buildSub(MI.getOperand(0).getReg(), MI.getOperand(1).getReg(),
ProdReg);
MI.eraseFromParent();
return Legalized;
}
case TargetOpcode::G_SMULO:
case TargetOpcode::G_UMULO: {
// Generate G_UMULH/G_SMULH to check for overflow and a normal G_MUL for the
// result.
unsigned Res = MI.getOperand(0).getReg();
unsigned Overflow = MI.getOperand(1).getReg();
unsigned LHS = MI.getOperand(2).getReg();
unsigned RHS = MI.getOperand(3).getReg();
MIRBuilder.buildMul(Res, LHS, RHS);
unsigned Opcode = MI.getOpcode() == TargetOpcode::G_SMULO
? TargetOpcode::G_SMULH
: TargetOpcode::G_UMULH;
unsigned HiPart = MRI.createGenericVirtualRegister(Ty);
MIRBuilder.buildInstr(Opcode)
.addDef(HiPart)
.addUse(LHS)
.addUse(RHS);
unsigned Zero = MRI.createGenericVirtualRegister(Ty);
MIRBuilder.buildConstant(Zero, 0);
// For *signed* multiply, overflow is detected by checking:
// (hi != (lo >> bitwidth-1))
if (Opcode == TargetOpcode::G_SMULH) {
unsigned Shifted = MRI.createGenericVirtualRegister(Ty);
unsigned ShiftAmt = MRI.createGenericVirtualRegister(Ty);
MIRBuilder.buildConstant(ShiftAmt, Ty.getSizeInBits() - 1);
MIRBuilder.buildInstr(TargetOpcode::G_ASHR)
.addDef(Shifted)
.addUse(Res)
.addUse(ShiftAmt);
MIRBuilder.buildICmp(CmpInst::ICMP_NE, Overflow, HiPart, Shifted);
} else {
MIRBuilder.buildICmp(CmpInst::ICMP_NE, Overflow, HiPart, Zero);
}
MI.eraseFromParent();
return Legalized;
}
case TargetOpcode::G_FNEG: {
// TODO: Handle vector types once we are able to
// represent them.
if (Ty.isVector())
return UnableToLegalize;
unsigned Res = MI.getOperand(0).getReg();
Type *ZeroTy;
LLVMContext &Ctx = MIRBuilder.getMF().getFunction().getContext();
switch (Ty.getSizeInBits()) {
case 16:
ZeroTy = Type::getHalfTy(Ctx);
break;
case 32:
ZeroTy = Type::getFloatTy(Ctx);
break;
case 64:
ZeroTy = Type::getDoubleTy(Ctx);
break;
case 128:
ZeroTy = Type::getFP128Ty(Ctx);
break;
default:
llvm_unreachable("unexpected floating-point type");
}
ConstantFP &ZeroForNegation =
*cast<ConstantFP>(ConstantFP::getZeroValueForNegation(ZeroTy));
auto Zero = MIRBuilder.buildFConstant(Ty, ZeroForNegation);
MIRBuilder.buildInstr(TargetOpcode::G_FSUB)
.addDef(Res)
.addUse(Zero->getOperand(0).getReg())
.addUse(MI.getOperand(1).getReg());
MI.eraseFromParent();
return Legalized;
}
case TargetOpcode::G_FSUB: {
// Lower (G_FSUB LHS, RHS) to (G_FADD LHS, (G_FNEG RHS)).
// First, check if G_FNEG is marked as Lower. If so, we may
// end up with an infinite loop as G_FSUB is used to legalize G_FNEG.
if (LI.getAction({G_FNEG, {Ty}}).Action == Lower)
return UnableToLegalize;
unsigned Res = MI.getOperand(0).getReg();
unsigned LHS = MI.getOperand(1).getReg();
unsigned RHS = MI.getOperand(2).getReg();
unsigned Neg = MRI.createGenericVirtualRegister(Ty);
MIRBuilder.buildInstr(TargetOpcode::G_FNEG).addDef(Neg).addUse(RHS);
MIRBuilder.buildInstr(TargetOpcode::G_FADD)
.addDef(Res)
.addUse(LHS)
.addUse(Neg);
MI.eraseFromParent();
return Legalized;
}
case TargetOpcode::G_ATOMIC_CMPXCHG_WITH_SUCCESS: {
unsigned OldValRes = MI.getOperand(0).getReg();
unsigned SuccessRes = MI.getOperand(1).getReg();
unsigned Addr = MI.getOperand(2).getReg();
unsigned CmpVal = MI.getOperand(3).getReg();
unsigned NewVal = MI.getOperand(4).getReg();
MIRBuilder.buildAtomicCmpXchg(OldValRes, Addr, CmpVal, NewVal,
**MI.memoperands_begin());
MIRBuilder.buildICmp(CmpInst::ICMP_EQ, SuccessRes, OldValRes, CmpVal);
MI.eraseFromParent();
return Legalized;
}
case TargetOpcode::G_LOAD:
case TargetOpcode::G_SEXTLOAD:
case TargetOpcode::G_ZEXTLOAD: {
// Lower to a memory-width G_LOAD and a G_SEXT/G_ZEXT/G_ANYEXT
unsigned DstReg = MI.getOperand(0).getReg();
unsigned PtrReg = MI.getOperand(1).getReg();
LLT DstTy = MRI.getType(DstReg);
auto &MMO = **MI.memoperands_begin();
if (DstTy.getSizeInBits() == MMO.getSize() /* in bytes */ * 8) {
// In the case of G_LOAD, this was a non-extending load already and we're
// about to lower to the same instruction.
if (MI.getOpcode() == TargetOpcode::G_LOAD)
return UnableToLegalize;
MIRBuilder.buildLoad(DstReg, PtrReg, MMO);
MI.eraseFromParent();
return Legalized;
}
if (DstTy.isScalar()) {
unsigned TmpReg = MRI.createGenericVirtualRegister(
LLT::scalar(MMO.getSize() /* in bytes */ * 8));
MIRBuilder.buildLoad(TmpReg, PtrReg, MMO);
switch (MI.getOpcode()) {
default:
llvm_unreachable("Unexpected opcode");
case TargetOpcode::G_LOAD:
MIRBuilder.buildAnyExt(DstReg, TmpReg);
break;
case TargetOpcode::G_SEXTLOAD:
MIRBuilder.buildSExt(DstReg, TmpReg);
break;
case TargetOpcode::G_ZEXTLOAD:
MIRBuilder.buildZExt(DstReg, TmpReg);
break;
}
MI.eraseFromParent();
return Legalized;
}
return UnableToLegalize;
}
}
}
LegalizerHelper::LegalizeResult
LegalizerHelper::fewerElementsVector(MachineInstr &MI, unsigned TypeIdx,
LLT NarrowTy) {
// FIXME: Don't know how to handle secondary types yet.
if (TypeIdx != 0)
return UnableToLegalize;
switch (MI.getOpcode()) {
default:
return UnableToLegalize;
case TargetOpcode::G_ADD: {
unsigned NarrowSize = NarrowTy.getSizeInBits();
unsigned DstReg = MI.getOperand(0).getReg();
unsigned Size = MRI.getType(DstReg).getSizeInBits();
int NumParts = Size / NarrowSize;
// FIXME: Don't know how to handle the situation where the small vectors
// aren't all the same size yet.
if (Size % NarrowSize != 0)
return UnableToLegalize;
MIRBuilder.setInstr(MI);
SmallVector<unsigned, 2> Src1Regs, Src2Regs, DstRegs;
extractParts(MI.getOperand(1).getReg(), NarrowTy, NumParts, Src1Regs);
extractParts(MI.getOperand(2).getReg(), NarrowTy, NumParts, Src2Regs);
for (int i = 0; i < NumParts; ++i) {
unsigned DstReg = MRI.createGenericVirtualRegister(NarrowTy);
MIRBuilder.buildAdd(DstReg, Src1Regs[i], Src2Regs[i]);
DstRegs.push_back(DstReg);
}
MIRBuilder.buildMerge(DstReg, DstRegs);
MI.eraseFromParent();
return Legalized;
}
}
}
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