caio/clang-p2996
1
0
Fork 0
Code Issues Pull Requests Actions Packages Projects Releases Wiki Activity
Files
fc8a08765af8f32663776a42e85b28362b5658ce
clang-p2996/llvm/lib/CodeGen/GlobalISel/Utils.cpp
Petar Avramovic 29f88b93fd [GlobalISel] Rework more/fewer elements for vectors 
Artifact combiner is not able to access individual elements after using
LCMTy style merge/unmerge, extract and insert to change vector number of
elements (pad with undef or split to sub-vector instructions).
Use unmerge to individual elements instead and then merge elements into
requested types.
Change argument lowering for vectors and moreElementsVector to use
buildPadVectorWithUndefElements and buildDeleteTrailingVectorElements.
FewerElementsVector had a few helpers that had different behavior,
introduce new helper for most of the opcodes.
FewerElementsVector helper is more flexible since it can create leftover
instruction smaller then requested type (useful in case target wants to
avoid pad with undef and use fewer registers). If target does not want
leftover of different type it should call more elements first.
Some helpers were performing more elements first to have split without
leftover. Opcodes that used this helper use clampMaxNumElementsStrict
(does more elements first) in LegalizerInfo to avoid test changes.
Fixes failures caused by failing to combine artifacts created during
more/fewer elements vector.

Differential Revision: https://reviews.llvm.org/D114198
2021-12-23 14:30:02 +01:00

1235 lines
42 KiB
C++
Raw Blame History

//===- llvm/CodeGen/GlobalISel/Utils.cpp -------------------------*- C++ -*-==//
//
// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
// See https://llvm.org/LICENSE.txt for license information.
// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
//
//===----------------------------------------------------------------------===//
/// \file This file implements the utility functions used by the GlobalISel
/// pipeline.
//===----------------------------------------------------------------------===//
#include "llvm/CodeGen/GlobalISel/Utils.h"
#include "llvm/ADT/APFloat.h"
#include "llvm/ADT/APInt.h"
#include "llvm/ADT/Optional.h"
#include "llvm/CodeGen/GlobalISel/GISelChangeObserver.h"
#include "llvm/CodeGen/GlobalISel/GISelKnownBits.h"
#include "llvm/CodeGen/GlobalISel/GenericMachineInstrs.h"
#include "llvm/CodeGen/GlobalISel/MIPatternMatch.h"
#include "llvm/CodeGen/GlobalISel/MachineIRBuilder.h"
#include "llvm/CodeGen/GlobalISel/RegisterBankInfo.h"
#include "llvm/CodeGen/MachineInstr.h"
#include "llvm/CodeGen/MachineInstrBuilder.h"
#include "llvm/CodeGen/MachineOptimizationRemarkEmitter.h"
#include "llvm/CodeGen/MachineSizeOpts.h"
#include "llvm/CodeGen/MachineRegisterInfo.h"
#include "llvm/CodeGen/StackProtector.h"
#include "llvm/CodeGen/TargetInstrInfo.h"
#include "llvm/CodeGen/TargetLowering.h"
#include "llvm/CodeGen/TargetPassConfig.h"
#include "llvm/CodeGen/TargetRegisterInfo.h"
#include "llvm/IR/Constants.h"
#include "llvm/Target/TargetMachine.h"
#define DEBUG_TYPE "globalisel-utils"
using namespace llvm;
using namespace MIPatternMatch;
Register llvm::constrainRegToClass(MachineRegisterInfo &MRI,
const TargetInstrInfo &TII,
const RegisterBankInfo &RBI, Register Reg,
const TargetRegisterClass &RegClass) {
if (!RBI.constrainGenericRegister(Reg, RegClass, MRI))
return MRI.createVirtualRegister(&RegClass);
return Reg;
}
Register llvm::constrainOperandRegClass(
const MachineFunction &MF, const TargetRegisterInfo &TRI,
MachineRegisterInfo &MRI, const TargetInstrInfo &TII,
const RegisterBankInfo &RBI, MachineInstr &InsertPt,
const TargetRegisterClass &RegClass, MachineOperand &RegMO) {
Register Reg = RegMO.getReg();
// Assume physical registers are properly constrained.
assert(Register::isVirtualRegister(Reg) && "PhysReg not implemented");
Register ConstrainedReg = constrainRegToClass(MRI, TII, RBI, Reg, RegClass);
// If we created a new virtual register because the class is not compatible
// then create a copy between the new and the old register.
if (ConstrainedReg != Reg) {
MachineBasicBlock::iterator InsertIt(&InsertPt);
MachineBasicBlock &MBB = *InsertPt.getParent();
// FIXME: The copy needs to have the classes constrained for its operands.
// Use operand's regbank to get the class for old register (Reg).
if (RegMO.isUse()) {
BuildMI(MBB, InsertIt, InsertPt.getDebugLoc(),
TII.get(TargetOpcode::COPY), ConstrainedReg)
.addReg(Reg);
} else {
assert(RegMO.isDef() && "Must be a definition");
BuildMI(MBB, std::next(InsertIt), InsertPt.getDebugLoc(),
TII.get(TargetOpcode::COPY), Reg)
.addReg(ConstrainedReg);
}
if (GISelChangeObserver *Observer = MF.getObserver()) {
Observer->changingInstr(*RegMO.getParent());
}
RegMO.setReg(ConstrainedReg);
if (GISelChangeObserver *Observer = MF.getObserver()) {
Observer->changedInstr(*RegMO.getParent());
}
} else {
if (GISelChangeObserver *Observer = MF.getObserver()) {
if (!RegMO.isDef()) {
MachineInstr *RegDef = MRI.getVRegDef(Reg);
Observer->changedInstr(*RegDef);
}
Observer->changingAllUsesOfReg(MRI, Reg);
Observer->finishedChangingAllUsesOfReg();
}
}
return ConstrainedReg;
}
Register llvm::constrainOperandRegClass(
const MachineFunction &MF, const TargetRegisterInfo &TRI,
MachineRegisterInfo &MRI, const TargetInstrInfo &TII,
const RegisterBankInfo &RBI, MachineInstr &InsertPt, const MCInstrDesc &II,
MachineOperand &RegMO, unsigned OpIdx) {
Register Reg = RegMO.getReg();
// Assume physical registers are properly constrained.
assert(Register::isVirtualRegister(Reg) && "PhysReg not implemented");
const TargetRegisterClass *OpRC = TII.getRegClass(II, OpIdx, &TRI, MF);
// Some of the target independent instructions, like COPY, may not impose any
// register class constraints on some of their operands: If it's a use, we can
// skip constraining as the instruction defining the register would constrain
// it.
if (OpRC) {
// Obtain the RC from incoming regbank if it is a proper sub-class. Operands
// can have multiple regbanks for a superclass that combine different
// register types (E.g., AMDGPU's VGPR and AGPR). The regbank ambiguity
// resolved by targets during regbankselect should not be overridden.
if (const auto *SubRC = TRI.getCommonSubClass(
OpRC, TRI.getConstrainedRegClassForOperand(RegMO, MRI)))
OpRC = SubRC;
OpRC = TRI.getAllocatableClass(OpRC);
}
if (!OpRC) {
assert((!isTargetSpecificOpcode(II.getOpcode()) || RegMO.isUse()) &&
"Register class constraint is required unless either the "
"instruction is target independent or the operand is a use");
// FIXME: Just bailing out like this here could be not enough, unless we
// expect the users of this function to do the right thing for PHIs and
// COPY:
// v1 = COPY v0
// v2 = COPY v1
// v1 here may end up not being constrained at all. Please notice that to
// reproduce the issue we likely need a destination pattern of a selection
// rule producing such extra copies, not just an input GMIR with them as
// every existing target using selectImpl handles copies before calling it
// and they never reach this function.
return Reg;
}
return constrainOperandRegClass(MF, TRI, MRI, TII, RBI, InsertPt, *OpRC,
RegMO);
}
bool llvm::constrainSelectedInstRegOperands(MachineInstr &I,
const TargetInstrInfo &TII,
const TargetRegisterInfo &TRI,
const RegisterBankInfo &RBI) {
assert(!isPreISelGenericOpcode(I.getOpcode()) &&
"A selected instruction is expected");
MachineBasicBlock &MBB = *I.getParent();
MachineFunction &MF = *MBB.getParent();
MachineRegisterInfo &MRI = MF.getRegInfo();
for (unsigned OpI = 0, OpE = I.getNumExplicitOperands(); OpI != OpE; ++OpI) {
MachineOperand &MO = I.getOperand(OpI);
// There's nothing to be done on non-register operands.
if (!MO.isReg())
continue;
LLVM_DEBUG(dbgs() << "Converting operand: " << MO << '\n');
assert(MO.isReg() && "Unsupported non-reg operand");
Register Reg = MO.getReg();
// Physical registers don't need to be constrained.
if (Register::isPhysicalRegister(Reg))
continue;
// Register operands with a value of 0 (e.g. predicate operands) don't need
// to be constrained.
if (Reg == 0)
continue;
// If the operand is a vreg, we should constrain its regclass, and only
// insert COPYs if that's impossible.
// constrainOperandRegClass does that for us.
constrainOperandRegClass(MF, TRI, MRI, TII, RBI, I, I.getDesc(), MO, OpI);
// Tie uses to defs as indicated in MCInstrDesc if this hasn't already been
// done.
if (MO.isUse()) {
int DefIdx = I.getDesc().getOperandConstraint(OpI, MCOI::TIED_TO);
if (DefIdx != -1 && !I.isRegTiedToUseOperand(DefIdx))
I.tieOperands(DefIdx, OpI);
}
}
return true;
}
bool llvm::canReplaceReg(Register DstReg, Register SrcReg,
MachineRegisterInfo &MRI) {
// Give up if either DstReg or SrcReg is a physical register.
if (DstReg.isPhysical() || SrcReg.isPhysical())
return false;
// Give up if the types don't match.
if (MRI.getType(DstReg) != MRI.getType(SrcReg))
return false;
// Replace if either DstReg has no constraints or the register
// constraints match.
return !MRI.getRegClassOrRegBank(DstReg) ||
MRI.getRegClassOrRegBank(DstReg) == MRI.getRegClassOrRegBank(SrcReg);
}
bool llvm::isTriviallyDead(const MachineInstr &MI,
const MachineRegisterInfo &MRI) {
// FIXME: This logical is mostly duplicated with
// DeadMachineInstructionElim::isDead. Why is LOCAL_ESCAPE not considered in
// MachineInstr::isLabel?
// Don't delete frame allocation labels.
if (MI.getOpcode() == TargetOpcode::LOCAL_ESCAPE)
return false;
// LIFETIME markers should be preserved even if they seem dead.
if (MI.getOpcode() == TargetOpcode::LIFETIME_START ||
MI.getOpcode() == TargetOpcode::LIFETIME_END)
return false;
// If we can move an instruction, we can remove it. Otherwise, it has
// a side-effect of some sort.
bool SawStore = false;
if (!MI.isSafeToMove(/*AA=*/nullptr, SawStore) && !MI.isPHI())
return false;
// Instructions without side-effects are dead iff they only define dead vregs.
for (auto &MO : MI.operands()) {
if (!MO.isReg() || !MO.isDef())
continue;
Register Reg = MO.getReg();
if (Register::isPhysicalRegister(Reg) || !MRI.use_nodbg_empty(Reg))
return false;
}
return true;
}
static void reportGISelDiagnostic(DiagnosticSeverity Severity,
MachineFunction &MF,
const TargetPassConfig &TPC,
MachineOptimizationRemarkEmitter &MORE,
MachineOptimizationRemarkMissed &R) {
bool IsFatal = Severity == DS_Error &&
TPC.isGlobalISelAbortEnabled();
// Print the function name explicitly if we don't have a debug location (which
// makes the diagnostic less useful) or if we're going to emit a raw error.
if (!R.getLocation().isValid() || IsFatal)
R << (" (in function: " + MF.getName() + ")").str();
if (IsFatal)
report_fatal_error(Twine(R.getMsg()));
else
MORE.emit(R);
}
void llvm::reportGISelWarning(MachineFunction &MF, const TargetPassConfig &TPC,
MachineOptimizationRemarkEmitter &MORE,
MachineOptimizationRemarkMissed &R) {
reportGISelDiagnostic(DS_Warning, MF, TPC, MORE, R);
}
void llvm::reportGISelFailure(MachineFunction &MF, const TargetPassConfig &TPC,
MachineOptimizationRemarkEmitter &MORE,
MachineOptimizationRemarkMissed &R) {
MF.getProperties().set(MachineFunctionProperties::Property::FailedISel);
reportGISelDiagnostic(DS_Error, MF, TPC, MORE, R);
}
void llvm::reportGISelFailure(MachineFunction &MF, const TargetPassConfig &TPC,
MachineOptimizationRemarkEmitter &MORE,
const char *PassName, StringRef Msg,
const MachineInstr &MI) {
MachineOptimizationRemarkMissed R(PassName, "GISelFailure: ",
MI.getDebugLoc(), MI.getParent());
R << Msg;
// Printing MI is expensive; only do it if expensive remarks are enabled.
if (TPC.isGlobalISelAbortEnabled() || MORE.allowExtraAnalysis(PassName))
R << ": " << ore::MNV("Inst", MI);
reportGISelFailure(MF, TPC, MORE, R);
}
Optional<APInt> llvm::getIConstantVRegVal(Register VReg,
const MachineRegisterInfo &MRI) {
Optional<ValueAndVReg> ValAndVReg = getIConstantVRegValWithLookThrough(
VReg, MRI, /*LookThroughInstrs*/ false);
assert((!ValAndVReg || ValAndVReg->VReg == VReg) &&
"Value found while looking through instrs");
if (!ValAndVReg)
return None;
return ValAndVReg->Value;
}
Optional<int64_t>
llvm::getIConstantVRegSExtVal(Register VReg, const MachineRegisterInfo &MRI) {
Optional<APInt> Val = getIConstantVRegVal(VReg, MRI);
if (Val && Val->getBitWidth() <= 64)
return Val->getSExtValue();
return None;
}
namespace {
typedef std::function<bool(const MachineInstr *)> IsOpcodeFn;
typedef std::function<Optional<APInt>(const MachineInstr *MI)> GetAPCstFn;
Optional<ValueAndVReg> getConstantVRegValWithLookThrough(
Register VReg, const MachineRegisterInfo &MRI, IsOpcodeFn IsConstantOpcode,
GetAPCstFn getAPCstValue, bool LookThroughInstrs = true,
bool LookThroughAnyExt = false) {
SmallVector<std::pair<unsigned, unsigned>, 4> SeenOpcodes;
MachineInstr *MI;
while ((MI = MRI.getVRegDef(VReg)) && !IsConstantOpcode(MI) &&
LookThroughInstrs) {
switch (MI->getOpcode()) {
case TargetOpcode::G_ANYEXT:
if (!LookThroughAnyExt)
return None;
LLVM_FALLTHROUGH;
case TargetOpcode::G_TRUNC:
case TargetOpcode::G_SEXT:
case TargetOpcode::G_ZEXT:
SeenOpcodes.push_back(std::make_pair(
MI->getOpcode(),
MRI.getType(MI->getOperand(0).getReg()).getSizeInBits()));
VReg = MI->getOperand(1).getReg();
break;
case TargetOpcode::COPY:
VReg = MI->getOperand(1).getReg();
if (Register::isPhysicalRegister(VReg))
return None;
break;
case TargetOpcode::G_INTTOPTR:
VReg = MI->getOperand(1).getReg();
break;
default:
return None;
}
}
if (!MI || !IsConstantOpcode(MI))
return None;
Optional<APInt> MaybeVal = getAPCstValue(MI);
if (!MaybeVal)
return None;
APInt &Val = *MaybeVal;
while (!SeenOpcodes.empty()) {
std::pair<unsigned, unsigned> OpcodeAndSize = SeenOpcodes.pop_back_val();
switch (OpcodeAndSize.first) {
case TargetOpcode::G_TRUNC:
Val = Val.trunc(OpcodeAndSize.second);
break;
case TargetOpcode::G_ANYEXT:
case TargetOpcode::G_SEXT:
Val = Val.sext(OpcodeAndSize.second);
break;
case TargetOpcode::G_ZEXT:
Val = Val.zext(OpcodeAndSize.second);
break;
}
}
return ValueAndVReg{Val, VReg};
}
bool isIConstant(const MachineInstr *MI) {
if (!MI)
return false;
return MI->getOpcode() == TargetOpcode::G_CONSTANT;
}
bool isFConstant(const MachineInstr *MI) {
if (!MI)
return false;
return MI->getOpcode() == TargetOpcode::G_FCONSTANT;
}
bool isAnyConstant(const MachineInstr *MI) {
if (!MI)
return false;
unsigned Opc = MI->getOpcode();
return Opc == TargetOpcode::G_CONSTANT || Opc == TargetOpcode::G_FCONSTANT;
}
Optional<APInt> getCImmAsAPInt(const MachineInstr *MI) {
const MachineOperand &CstVal = MI->getOperand(1);
if (CstVal.isCImm())
return CstVal.getCImm()->getValue();
return None;
}
Optional<APInt> getCImmOrFPImmAsAPInt(const MachineInstr *MI) {
const MachineOperand &CstVal = MI->getOperand(1);
if (CstVal.isCImm())
return CstVal.getCImm()->getValue();
if (CstVal.isFPImm())
return CstVal.getFPImm()->getValueAPF().bitcastToAPInt();
return None;
}
} // end anonymous namespace
Optional<ValueAndVReg> llvm::getIConstantVRegValWithLookThrough(
Register VReg, const MachineRegisterInfo &MRI, bool LookThroughInstrs) {
return getConstantVRegValWithLookThrough(VReg, MRI, isIConstant,
getCImmAsAPInt, LookThroughInstrs);
}
Optional<ValueAndVReg> llvm::getAnyConstantVRegValWithLookThrough(
Register VReg, const MachineRegisterInfo &MRI, bool LookThroughInstrs,
bool LookThroughAnyExt) {
return getConstantVRegValWithLookThrough(
VReg, MRI, isAnyConstant, getCImmOrFPImmAsAPInt, LookThroughInstrs,
LookThroughAnyExt);
}
Optional<FPValueAndVReg> llvm::getFConstantVRegValWithLookThrough(
Register VReg, const MachineRegisterInfo &MRI, bool LookThroughInstrs) {
auto Reg = getConstantVRegValWithLookThrough(
VReg, MRI, isFConstant, getCImmOrFPImmAsAPInt, LookThroughInstrs);
if (!Reg)
return None;
return FPValueAndVReg{getConstantFPVRegVal(Reg->VReg, MRI)->getValueAPF(),
Reg->VReg};
}
const ConstantFP *
llvm::getConstantFPVRegVal(Register VReg, const MachineRegisterInfo &MRI) {
MachineInstr *MI = MRI.getVRegDef(VReg);
if (TargetOpcode::G_FCONSTANT != MI->getOpcode())
return nullptr;
return MI->getOperand(1).getFPImm();
}
Optional<DefinitionAndSourceRegister>
llvm::getDefSrcRegIgnoringCopies(Register Reg, const MachineRegisterInfo &MRI) {
Register DefSrcReg = Reg;
auto *DefMI = MRI.getVRegDef(Reg);
auto DstTy = MRI.getType(DefMI->getOperand(0).getReg());
if (!DstTy.isValid())
return None;
unsigned Opc = DefMI->getOpcode();
while (Opc == TargetOpcode::COPY || isPreISelGenericOptimizationHint(Opc)) {
Register SrcReg = DefMI->getOperand(1).getReg();
auto SrcTy = MRI.getType(SrcReg);
if (!SrcTy.isValid())
break;
DefMI = MRI.getVRegDef(SrcReg);
DefSrcReg = SrcReg;
Opc = DefMI->getOpcode();
}
return DefinitionAndSourceRegister{DefMI, DefSrcReg};
}
MachineInstr *llvm::getDefIgnoringCopies(Register Reg,
const MachineRegisterInfo &MRI) {
Optional<DefinitionAndSourceRegister> DefSrcReg =
getDefSrcRegIgnoringCopies(Reg, MRI);
return DefSrcReg ? DefSrcReg->MI : nullptr;
}
Register llvm::getSrcRegIgnoringCopies(Register Reg,
const MachineRegisterInfo &MRI) {
Optional<DefinitionAndSourceRegister> DefSrcReg =
getDefSrcRegIgnoringCopies(Reg, MRI);
return DefSrcReg ? DefSrcReg->Reg : Register();
}
MachineInstr *llvm::getOpcodeDef(unsigned Opcode, Register Reg,
const MachineRegisterInfo &MRI) {
MachineInstr *DefMI = getDefIgnoringCopies(Reg, MRI);
return DefMI && DefMI->getOpcode() == Opcode ? DefMI : nullptr;
}
APFloat llvm::getAPFloatFromSize(double Val, unsigned Size) {
if (Size == 32)
return APFloat(float(Val));
if (Size == 64)
return APFloat(Val);
if (Size != 16)
llvm_unreachable("Unsupported FPConstant size");
bool Ignored;
APFloat APF(Val);
APF.convert(APFloat::IEEEhalf(), APFloat::rmNearestTiesToEven, &Ignored);
return APF;
}
Optional<APInt> llvm::ConstantFoldBinOp(unsigned Opcode, const Register Op1,
const Register Op2,
const MachineRegisterInfo &MRI) {
auto MaybeOp2Cst = getAnyConstantVRegValWithLookThrough(Op2, MRI, false);
if (!MaybeOp2Cst)
return None;
auto MaybeOp1Cst = getAnyConstantVRegValWithLookThrough(Op1, MRI, false);
if (!MaybeOp1Cst)
return None;
const APInt &C1 = MaybeOp1Cst->Value;
const APInt &C2 = MaybeOp2Cst->Value;
switch (Opcode) {
default:
break;
case TargetOpcode::G_ADD:
return C1 + C2;
case TargetOpcode::G_AND:
return C1 & C2;
case TargetOpcode::G_ASHR:
return C1.ashr(C2);
case TargetOpcode::G_LSHR:
return C1.lshr(C2);
case TargetOpcode::G_MUL:
return C1 * C2;
case TargetOpcode::G_OR:
return C1 | C2;
case TargetOpcode::G_SHL:
return C1 << C2;
case TargetOpcode::G_SUB:
return C1 - C2;
case TargetOpcode::G_XOR:
return C1 ^ C2;
case TargetOpcode::G_UDIV:
if (!C2.getBoolValue())
break;
return C1.udiv(C2);
case TargetOpcode::G_SDIV:
if (!C2.getBoolValue())
break;
return C1.sdiv(C2);
case TargetOpcode::G_UREM:
if (!C2.getBoolValue())
break;
return C1.urem(C2);
case TargetOpcode::G_SREM:
if (!C2.getBoolValue())
break;
return C1.srem(C2);
}
return None;
}
Optional<APFloat> llvm::ConstantFoldFPBinOp(unsigned Opcode, const Register Op1,
const Register Op2,
const MachineRegisterInfo &MRI) {
const ConstantFP *Op2Cst = getConstantFPVRegVal(Op2, MRI);
if (!Op2Cst)
return None;
const ConstantFP *Op1Cst = getConstantFPVRegVal(Op1, MRI);
if (!Op1Cst)
return None;
APFloat C1 = Op1Cst->getValueAPF();
const APFloat &C2 = Op2Cst->getValueAPF();
switch (Opcode) {
case TargetOpcode::G_FADD:
C1.add(C2, APFloat::rmNearestTiesToEven);
return C1;
case TargetOpcode::G_FSUB:
C1.subtract(C2, APFloat::rmNearestTiesToEven);
return C1;
case TargetOpcode::G_FMUL:
C1.multiply(C2, APFloat::rmNearestTiesToEven);
return C1;
case TargetOpcode::G_FDIV:
C1.divide(C2, APFloat::rmNearestTiesToEven);
return C1;
case TargetOpcode::G_FREM:
C1.mod(C2);
return C1;
case TargetOpcode::G_FCOPYSIGN:
C1.copySign(C2);
return C1;
case TargetOpcode::G_FMINNUM:
return minnum(C1, C2);
case TargetOpcode::G_FMAXNUM:
return maxnum(C1, C2);
case TargetOpcode::G_FMINIMUM:
return minimum(C1, C2);
case TargetOpcode::G_FMAXIMUM:
return maximum(C1, C2);
case TargetOpcode::G_FMINNUM_IEEE:
case TargetOpcode::G_FMAXNUM_IEEE:
// FIXME: These operations were unfortunately named. fminnum/fmaxnum do not
// follow the IEEE behavior for signaling nans and follow libm's fmin/fmax,
// and currently there isn't a nice wrapper in APFloat for the version with
// correct snan handling.
break;
default:
break;
}
return None;
}
Optional<MachineInstr *>
llvm::ConstantFoldVectorBinop(unsigned Opcode, const Register Op1,
const Register Op2,
const MachineRegisterInfo &MRI,
MachineIRBuilder &MIB) {
auto *SrcVec1 = getOpcodeDef<GBuildVector>(Op1, MRI);
if (!SrcVec1)
return None;
auto *SrcVec2 = getOpcodeDef<GBuildVector>(Op2, MRI);
if (!SrcVec2)
return None;
const LLT EltTy = MRI.getType(SrcVec1->getSourceReg(0));
SmallVector<Register, 16> FoldedElements;
for (unsigned Idx = 0, E = SrcVec1->getNumSources(); Idx < E; ++Idx) {
auto MaybeCst = ConstantFoldBinOp(Opcode, SrcVec1->getSourceReg(Idx),
SrcVec2->getSourceReg(Idx), MRI);
if (!MaybeCst)
return None;
auto FoldedCstReg = MIB.buildConstant(EltTy, *MaybeCst).getReg(0);
FoldedElements.emplace_back(FoldedCstReg);
}
// Create the new vector constant.
auto CstVec =
MIB.buildBuildVector(MRI.getType(SrcVec1->getReg(0)), FoldedElements);
return &*CstVec;
}
bool llvm::isKnownNeverNaN(Register Val, const MachineRegisterInfo &MRI,
bool SNaN) {
const MachineInstr *DefMI = MRI.getVRegDef(Val);
if (!DefMI)
return false;
const TargetMachine& TM = DefMI->getMF()->getTarget();
if (DefMI->getFlag(MachineInstr::FmNoNans) || TM.Options.NoNaNsFPMath)
return true;
// If the value is a constant, we can obviously see if it is a NaN or not.
if (const ConstantFP *FPVal = getConstantFPVRegVal(Val, MRI)) {
return !FPVal->getValueAPF().isNaN() ||
(SNaN && !FPVal->getValueAPF().isSignaling());
}
if (DefMI->getOpcode() == TargetOpcode::G_BUILD_VECTOR) {
for (const auto &Op : DefMI->uses())
if (!isKnownNeverNaN(Op.getReg(), MRI, SNaN))
return false;
return true;
}
switch (DefMI->getOpcode()) {
default:
break;
case TargetOpcode::G_FMINNUM_IEEE:
case TargetOpcode::G_FMAXNUM_IEEE: {
if (SNaN)
return true;
// This can return a NaN if either operand is an sNaN, or if both operands
// are NaN.
return (isKnownNeverNaN(DefMI->getOperand(1).getReg(), MRI) &&
isKnownNeverSNaN(DefMI->getOperand(2).getReg(), MRI)) ||
(isKnownNeverSNaN(DefMI->getOperand(1).getReg(), MRI) &&
isKnownNeverNaN(DefMI->getOperand(2).getReg(), MRI));
}
case TargetOpcode::G_FMINNUM:
case TargetOpcode::G_FMAXNUM: {
// Only one needs to be known not-nan, since it will be returned if the
// other ends up being one.
return isKnownNeverNaN(DefMI->getOperand(1).getReg(), MRI, SNaN) ||
isKnownNeverNaN(DefMI->getOperand(2).getReg(), MRI, SNaN);
}
}
if (SNaN) {
// FP operations quiet. For now, just handle the ones inserted during
// legalization.
switch (DefMI->getOpcode()) {
case TargetOpcode::G_FPEXT:
case TargetOpcode::G_FPTRUNC:
case TargetOpcode::G_FCANONICALIZE:
return true;
default:
return false;
}
}
return false;
}
Align llvm::inferAlignFromPtrInfo(MachineFunction &MF,
const MachinePointerInfo &MPO) {
auto PSV = MPO.V.dyn_cast<const PseudoSourceValue *>();
if (auto FSPV = dyn_cast_or_null<FixedStackPseudoSourceValue>(PSV)) {
MachineFrameInfo &MFI = MF.getFrameInfo();
return commonAlignment(MFI.getObjectAlign(FSPV->getFrameIndex()),
MPO.Offset);
}
if (const Value *V = MPO.V.dyn_cast<const Value *>()) {
const Module *M = MF.getFunction().getParent();
return V->getPointerAlignment(M->getDataLayout());
}
return Align(1);
}
Register llvm::getFunctionLiveInPhysReg(MachineFunction &MF,
const TargetInstrInfo &TII,
MCRegister PhysReg,
const TargetRegisterClass &RC,
LLT RegTy) {
DebugLoc DL; // FIXME: Is no location the right choice?
MachineBasicBlock &EntryMBB = MF.front();
MachineRegisterInfo &MRI = MF.getRegInfo();
Register LiveIn = MRI.getLiveInVirtReg(PhysReg);
if (LiveIn) {
MachineInstr *Def = MRI.getVRegDef(LiveIn);
if (Def) {
// FIXME: Should the verifier check this is in the entry block?
assert(Def->getParent() == &EntryMBB && "live-in copy not in entry block");
return LiveIn;
}
// It's possible the incoming argument register and copy was added during
// lowering, but later deleted due to being/becoming dead. If this happens,
// re-insert the copy.
} else {
// The live in register was not present, so add it.
LiveIn = MF.addLiveIn(PhysReg, &RC);
if (RegTy.isValid())
MRI.setType(LiveIn, RegTy);
}
BuildMI(EntryMBB, EntryMBB.begin(), DL, TII.get(TargetOpcode::COPY), LiveIn)
.addReg(PhysReg);
if (!EntryMBB.isLiveIn(PhysReg))
EntryMBB.addLiveIn(PhysReg);
return LiveIn;
}
Optional<APInt> llvm::ConstantFoldExtOp(unsigned Opcode, const Register Op1,
uint64_t Imm,
const MachineRegisterInfo &MRI) {
auto MaybeOp1Cst = getIConstantVRegVal(Op1, MRI);
if (MaybeOp1Cst) {
switch (Opcode) {
default:
break;
case TargetOpcode::G_SEXT_INREG: {
LLT Ty = MRI.getType(Op1);
return MaybeOp1Cst->trunc(Imm).sext(Ty.getScalarSizeInBits());
}
}
}
return None;
}
Optional<APFloat> llvm::ConstantFoldIntToFloat(unsigned Opcode, LLT DstTy,
Register Src,
const MachineRegisterInfo &MRI) {
assert(Opcode == TargetOpcode::G_SITOFP || Opcode == TargetOpcode::G_UITOFP);
if (auto MaybeSrcVal = getIConstantVRegVal(Src, MRI)) {
APFloat DstVal(getFltSemanticForLLT(DstTy));
DstVal.convertFromAPInt(*MaybeSrcVal, Opcode == TargetOpcode::G_SITOFP,
APFloat::rmNearestTiesToEven);
return DstVal;
}
return None;
}
Optional<SmallVector<unsigned>>
llvm::ConstantFoldCTLZ(Register Src, const MachineRegisterInfo &MRI) {
LLT Ty = MRI.getType(Src);
SmallVector<unsigned> FoldedCTLZs;
auto tryFoldScalar = [&](Register R) -> Optional<unsigned> {
auto MaybeCst = getIConstantVRegVal(R, MRI);
if (!MaybeCst)
return None;
return MaybeCst->countLeadingZeros();
};
if (Ty.isVector()) {
// Try to constant fold each element.
auto *BV = getOpcodeDef<GBuildVector>(Src, MRI);
if (!BV)
return None;
for (unsigned SrcIdx = 0; SrcIdx < BV->getNumSources(); ++SrcIdx) {
if (auto MaybeFold = tryFoldScalar(BV->getSourceReg(SrcIdx))) {
FoldedCTLZs.emplace_back(*MaybeFold);
continue;
}
return None;
}
return FoldedCTLZs;
}
if (auto MaybeCst = tryFoldScalar(Src)) {
FoldedCTLZs.emplace_back(*MaybeCst);
return FoldedCTLZs;
}
return None;
}
bool llvm::isKnownToBeAPowerOfTwo(Register Reg, const MachineRegisterInfo &MRI,
GISelKnownBits *KB) {
Optional<DefinitionAndSourceRegister> DefSrcReg =
getDefSrcRegIgnoringCopies(Reg, MRI);
if (!DefSrcReg)
return false;
const MachineInstr &MI = *DefSrcReg->MI;
const LLT Ty = MRI.getType(Reg);
switch (MI.getOpcode()) {
case TargetOpcode::G_CONSTANT: {
unsigned BitWidth = Ty.getScalarSizeInBits();
const ConstantInt *CI = MI.getOperand(1).getCImm();
return CI->getValue().zextOrTrunc(BitWidth).isPowerOf2();
}
case TargetOpcode::G_SHL: {
// A left-shift of a constant one will have exactly one bit set because
// shifting the bit off the end is undefined.
// TODO: Constant splat
if (auto ConstLHS = getIConstantVRegVal(MI.getOperand(1).getReg(), MRI)) {
if (*ConstLHS == 1)
return true;
}
break;
}
case TargetOpcode::G_LSHR: {
if (auto ConstLHS = getIConstantVRegVal(MI.getOperand(1).getReg(), MRI)) {
if (ConstLHS->isSignMask())
return true;
}
break;
}
case TargetOpcode::G_BUILD_VECTOR: {
// TODO: Probably should have a recursion depth guard since you could have
// bitcasted vector elements.
for (const MachineOperand &MO : llvm::drop_begin(MI.operands()))
if (!isKnownToBeAPowerOfTwo(MO.getReg(), MRI, KB))
return false;
return true;
}
case TargetOpcode::G_BUILD_VECTOR_TRUNC: {
// Only handle constants since we would need to know if number of leading
// zeros is greater than the truncation amount.
const unsigned BitWidth = Ty.getScalarSizeInBits();
for (const MachineOperand &MO : llvm::drop_begin(MI.operands())) {
auto Const = getIConstantVRegVal(MO.getReg(), MRI);
if (!Const || !Const->zextOrTrunc(BitWidth).isPowerOf2())
return false;
}
return true;
}
default:
break;
}
if (!KB)
return false;
// More could be done here, though the above checks are enough
// to handle some common cases.
// Fall back to computeKnownBits to catch other known cases.
KnownBits Known = KB->getKnownBits(Reg);
return (Known.countMaxPopulation() == 1) && (Known.countMinPopulation() == 1);
}
void llvm::getSelectionDAGFallbackAnalysisUsage(AnalysisUsage &AU) {
AU.addPreserved<StackProtector>();
}
static unsigned getLCMSize(unsigned OrigSize, unsigned TargetSize) {
unsigned Mul = OrigSize * TargetSize;
unsigned GCDSize = greatestCommonDivisor(OrigSize, TargetSize);
return Mul / GCDSize;
}
LLT llvm::getLCMType(LLT OrigTy, LLT TargetTy) {
const unsigned OrigSize = OrigTy.getSizeInBits();
const unsigned TargetSize = TargetTy.getSizeInBits();
if (OrigSize == TargetSize)
return OrigTy;
if (OrigTy.isVector()) {
const LLT OrigElt = OrigTy.getElementType();
if (TargetTy.isVector()) {
const LLT TargetElt = TargetTy.getElementType();
if (OrigElt.getSizeInBits() == TargetElt.getSizeInBits()) {
int GCDElts = greatestCommonDivisor(OrigTy.getNumElements(),
TargetTy.getNumElements());
// Prefer the original element type.
ElementCount Mul = OrigTy.getElementCount() * TargetTy.getNumElements();
return LLT::vector(Mul.divideCoefficientBy(GCDElts),
OrigTy.getElementType());
}
} else {
if (OrigElt.getSizeInBits() == TargetSize)
return OrigTy;
}
unsigned LCMSize = getLCMSize(OrigSize, TargetSize);
return LLT::fixed_vector(LCMSize / OrigElt.getSizeInBits(), OrigElt);
}
if (TargetTy.isVector()) {
unsigned LCMSize = getLCMSize(OrigSize, TargetSize);
return LLT::fixed_vector(LCMSize / OrigSize, OrigTy);
}
unsigned LCMSize = getLCMSize(OrigSize, TargetSize);
// Preserve pointer types.
if (LCMSize == OrigSize)
return OrigTy;
if (LCMSize == TargetSize)
return TargetTy;
return LLT::scalar(LCMSize);
}
LLT llvm::getCoverTy(LLT OrigTy, LLT TargetTy) {
if (!OrigTy.isVector() || !TargetTy.isVector() || OrigTy == TargetTy ||
(OrigTy.getScalarSizeInBits() != TargetTy.getScalarSizeInBits()))
return getLCMType(OrigTy, TargetTy);
unsigned OrigTyNumElts = OrigTy.getNumElements();
unsigned TargetTyNumElts = TargetTy.getNumElements();
if (OrigTyNumElts % TargetTyNumElts == 0)
return OrigTy;
unsigned NumElts = alignTo(OrigTyNumElts, TargetTyNumElts);
return LLT::scalarOrVector(ElementCount::getFixed(NumElts),
OrigTy.getElementType());
}
LLT llvm::getGCDType(LLT OrigTy, LLT TargetTy) {
const unsigned OrigSize = OrigTy.getSizeInBits();
const unsigned TargetSize = TargetTy.getSizeInBits();
if (OrigSize == TargetSize)
return OrigTy;
if (OrigTy.isVector()) {
LLT OrigElt = OrigTy.getElementType();
if (TargetTy.isVector()) {
LLT TargetElt = TargetTy.getElementType();
if (OrigElt.getSizeInBits() == TargetElt.getSizeInBits()) {
int GCD = greatestCommonDivisor(OrigTy.getNumElements(),
TargetTy.getNumElements());
return LLT::scalarOrVector(ElementCount::getFixed(GCD), OrigElt);
}
} else {
// If the source is a vector of pointers, return a pointer element.
if (OrigElt.getSizeInBits() == TargetSize)
return OrigElt;
}
unsigned GCD = greatestCommonDivisor(OrigSize, TargetSize);
if (GCD == OrigElt.getSizeInBits())
return OrigElt;
// If we can't produce the original element type, we have to use a smaller
// scalar.
if (GCD < OrigElt.getSizeInBits())
return LLT::scalar(GCD);
return LLT::fixed_vector(GCD / OrigElt.getSizeInBits(), OrigElt);
}
if (TargetTy.isVector()) {
// Try to preserve the original element type.
LLT TargetElt = TargetTy.getElementType();
if (TargetElt.getSizeInBits() == OrigSize)
return OrigTy;
}
unsigned GCD = greatestCommonDivisor(OrigSize, TargetSize);
return LLT::scalar(GCD);
}
Optional<int> llvm::getSplatIndex(MachineInstr &MI) {
assert(MI.getOpcode() == TargetOpcode::G_SHUFFLE_VECTOR &&
"Only G_SHUFFLE_VECTOR can have a splat index!");
ArrayRef<int> Mask = MI.getOperand(3).getShuffleMask();
auto FirstDefinedIdx = find_if(Mask, [](int Elt) { return Elt >= 0; });
// If all elements are undefined, this shuffle can be considered a splat.
// Return 0 for better potential for callers to simplify.
if (FirstDefinedIdx == Mask.end())
return 0;
// Make sure all remaining elements are either undef or the same
// as the first non-undef value.
int SplatValue = *FirstDefinedIdx;
if (any_of(make_range(std::next(FirstDefinedIdx), Mask.end()),
[&SplatValue](int Elt) { return Elt >= 0 && Elt != SplatValue; }))
return None;
return SplatValue;
}
static bool isBuildVectorOp(unsigned Opcode) {
return Opcode == TargetOpcode::G_BUILD_VECTOR ||
Opcode == TargetOpcode::G_BUILD_VECTOR_TRUNC;
}
namespace {
Optional<ValueAndVReg> getAnyConstantSplat(Register VReg,
const MachineRegisterInfo &MRI,
bool AllowUndef) {
MachineInstr *MI = getDefIgnoringCopies(VReg, MRI);
if (!MI)
return None;
if (!isBuildVectorOp(MI->getOpcode()))
return None;
Optional<ValueAndVReg> SplatValAndReg = None;
for (MachineOperand &Op : MI->uses()) {
Register Element = Op.getReg();
auto ElementValAndReg =
getAnyConstantVRegValWithLookThrough(Element, MRI, true, true);
// If AllowUndef, treat undef as value that will result in a constant splat.
if (!ElementValAndReg) {
if (AllowUndef && isa<GImplicitDef>(MRI.getVRegDef(Element)))
continue;
return None;
}
// Record splat value
if (!SplatValAndReg)
SplatValAndReg = ElementValAndReg;
// Different constant then the one already recorded, not a constant splat.
if (SplatValAndReg->Value != ElementValAndReg->Value)
return None;
}
return SplatValAndReg;
}
} // end anonymous namespace
bool llvm::isBuildVectorConstantSplat(const Register Reg,
const MachineRegisterInfo &MRI,
int64_t SplatValue, bool AllowUndef) {
if (auto SplatValAndReg = getAnyConstantSplat(Reg, MRI, AllowUndef))
return mi_match(SplatValAndReg->VReg, MRI, m_SpecificICst(SplatValue));
return false;
}
bool llvm::isBuildVectorConstantSplat(const MachineInstr &MI,
const MachineRegisterInfo &MRI,
int64_t SplatValue, bool AllowUndef) {
return isBuildVectorConstantSplat(MI.getOperand(0).getReg(), MRI, SplatValue,
AllowUndef);
}
Optional<int64_t>
llvm::getBuildVectorConstantSplat(const MachineInstr &MI,
const MachineRegisterInfo &MRI) {
if (auto SplatValAndReg =
getAnyConstantSplat(MI.getOperand(0).getReg(), MRI, false))
return getIConstantVRegSExtVal(SplatValAndReg->VReg, MRI);
return None;
}
Optional<FPValueAndVReg> llvm::getFConstantSplat(Register VReg,
const MachineRegisterInfo &MRI,
bool AllowUndef) {
if (auto SplatValAndReg = getAnyConstantSplat(VReg, MRI, AllowUndef))
return getFConstantVRegValWithLookThrough(SplatValAndReg->VReg, MRI);
return None;
}
bool llvm::isBuildVectorAllZeros(const MachineInstr &MI,
const MachineRegisterInfo &MRI,
bool AllowUndef) {
return isBuildVectorConstantSplat(MI, MRI, 0, AllowUndef);
}
bool llvm::isBuildVectorAllOnes(const MachineInstr &MI,
const MachineRegisterInfo &MRI,
bool AllowUndef) {
return isBuildVectorConstantSplat(MI, MRI, -1, AllowUndef);
}
Optional<RegOrConstant> llvm::getVectorSplat(const MachineInstr &MI,
const MachineRegisterInfo &MRI) {
unsigned Opc = MI.getOpcode();
if (!isBuildVectorOp(Opc))
return None;
if (auto Splat = getBuildVectorConstantSplat(MI, MRI))
return RegOrConstant(*Splat);
auto Reg = MI.getOperand(1).getReg();
if (any_of(make_range(MI.operands_begin() + 2, MI.operands_end()),
[&Reg](const MachineOperand &Op) { return Op.getReg() != Reg; }))
return None;
return RegOrConstant(Reg);
}
bool llvm::isConstantOrConstantVector(MachineInstr &MI,
const MachineRegisterInfo &MRI) {
Register Def = MI.getOperand(0).getReg();
if (auto C = getIConstantVRegValWithLookThrough(Def, MRI))
return true;
GBuildVector *BV = dyn_cast<GBuildVector>(&MI);
if (!BV)
return false;
for (unsigned SrcIdx = 0; SrcIdx < BV->getNumSources(); ++SrcIdx) {
if (getIConstantVRegValWithLookThrough(BV->getSourceReg(SrcIdx), MRI) ||
getOpcodeDef<GImplicitDef>(BV->getSourceReg(SrcIdx), MRI))
continue;
return false;
}
return true;
}
Optional<APInt>
llvm::isConstantOrConstantSplatVector(MachineInstr &MI,
const MachineRegisterInfo &MRI) {
Register Def = MI.getOperand(0).getReg();
if (auto C = getIConstantVRegValWithLookThrough(Def, MRI))
return C->Value;
auto MaybeCst = getBuildVectorConstantSplat(MI, MRI);
if (!MaybeCst)
return None;
const unsigned ScalarSize = MRI.getType(Def).getScalarSizeInBits();
return APInt(ScalarSize, *MaybeCst, true);
}
bool llvm::matchUnaryPredicate(
const MachineRegisterInfo &MRI, Register Reg,
std::function<bool(const Constant *ConstVal)> Match, bool AllowUndefs) {
const MachineInstr *Def = getDefIgnoringCopies(Reg, MRI);
if (AllowUndefs && Def->getOpcode() == TargetOpcode::G_IMPLICIT_DEF)
return Match(nullptr);
// TODO: Also handle fconstant
if (Def->getOpcode() == TargetOpcode::G_CONSTANT)
return Match(Def->getOperand(1).getCImm());
if (Def->getOpcode() != TargetOpcode::G_BUILD_VECTOR)
return false;
for (unsigned I = 1, E = Def->getNumOperands(); I != E; ++I) {
Register SrcElt = Def->getOperand(I).getReg();
const MachineInstr *SrcDef = getDefIgnoringCopies(SrcElt, MRI);
if (AllowUndefs && SrcDef->getOpcode() == TargetOpcode::G_IMPLICIT_DEF) {
if (!Match(nullptr))
return false;
continue;
}
if (SrcDef->getOpcode() != TargetOpcode::G_CONSTANT ||
!Match(SrcDef->getOperand(1).getCImm()))
return false;
}
return true;
}
bool llvm::isConstTrueVal(const TargetLowering &TLI, int64_t Val, bool IsVector,
bool IsFP) {
switch (TLI.getBooleanContents(IsVector, IsFP)) {
case TargetLowering::UndefinedBooleanContent:
return Val & 0x1;
case TargetLowering::ZeroOrOneBooleanContent:
return Val == 1;
case TargetLowering::ZeroOrNegativeOneBooleanContent:
return Val == -1;
}
llvm_unreachable("Invalid boolean contents");
}
int64_t llvm::getICmpTrueVal(const TargetLowering &TLI, bool IsVector,
bool IsFP) {
switch (TLI.getBooleanContents(IsVector, IsFP)) {
case TargetLowering::UndefinedBooleanContent:
case TargetLowering::ZeroOrOneBooleanContent:
return 1;
case TargetLowering::ZeroOrNegativeOneBooleanContent:
return -1;
}
llvm_unreachable("Invalid boolean contents");
}
bool llvm::shouldOptForSize(const MachineBasicBlock &MBB,
ProfileSummaryInfo *PSI, BlockFrequencyInfo *BFI) {
const auto &F = MBB.getParent()->getFunction();
return F.hasOptSize() || F.hasMinSize() ||
llvm::shouldOptimizeForSize(MBB.getBasicBlock(), PSI, BFI);
}
void llvm::saveUsesAndErase(MachineInstr &MI, MachineRegisterInfo &MRI,
LostDebugLocObserver *LocObserver,
SmallInstListTy &DeadInstChain) {
for (MachineOperand &Op : MI.uses()) {
if (Op.isReg() && Op.getReg().isVirtual())
DeadInstChain.insert(MRI.getVRegDef(Op.getReg()));
}
LLVM_DEBUG(dbgs() << MI << "Is dead; erasing.\n");
DeadInstChain.remove(&MI);
MI.eraseFromParent();
if (LocObserver)
LocObserver->checkpoint(false);
}
void llvm::eraseInstrs(ArrayRef<MachineInstr *> DeadInstrs,
MachineRegisterInfo &MRI,
LostDebugLocObserver *LocObserver) {
SmallInstListTy DeadInstChain;
for (MachineInstr *MI : DeadInstrs)
saveUsesAndErase(*MI, MRI, LocObserver, DeadInstChain);
while (!DeadInstChain.empty()) {
MachineInstr *Inst = DeadInstChain.pop_back_val();
if (!isTriviallyDead(*Inst, MRI))
continue;
saveUsesAndErase(*Inst, MRI, LocObserver, DeadInstChain);
}
}
void llvm::eraseInstr(MachineInstr &MI, MachineRegisterInfo &MRI,
LostDebugLocObserver *LocObserver) {
return eraseInstrs({&MI}, MRI, LocObserver);
}
Reference in New Issue View Git Blame Copy Permalink