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merged 2 commits into from
Jul 3, 2024
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[CVP][LVI] Add support for vectors #97428

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[CVP][LVI] Add support for vectors
nikic Jul 2, 2024
0ecfcc6
add scalable vector support
nikic Jul 3, 2024
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28 changes: 24 additions & 4 deletions llvm/lib/Analysis/LazyValueInfo.cpp
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Original file line number Diff line number Diff line change
Expand Up @@ -650,7 +650,7 @@ LazyValueInfoImpl::solveBlockValueImpl(Value *Val, BasicBlock *BB) {
if (PT && isKnownNonZero(BBI, DL))
return ValueLatticeElement::getNot(ConstantPointerNull::get(PT));

if (BBI->getType()->isIntegerTy()) {
if (BBI->getType()->isIntOrIntVectorTy()) {
if (auto *CI = dyn_cast<CastInst>(BBI))
return solveBlockValueCast(CI, BB);

Expand Down Expand Up @@ -836,6 +836,24 @@ void LazyValueInfoImpl::intersectAssumeOrGuardBlockValueConstantRange(
}
}

static ConstantRange getConstantRangeFromVector(Constant *C,
FixedVectorType *Ty) {
unsigned BW = Ty->getScalarSizeInBits();
ConstantRange CR = ConstantRange::getEmpty(BW);
for (unsigned I = 0; I < Ty->getNumElements(); ++I) {
Constant *Elem = C->getAggregateElement(I);
if (!Elem)
return ConstantRange::getFull(BW);
if (isa<PoisonValue>(Elem))
continue;
auto *CI = dyn_cast<ConstantInt>(Elem);
if (!CI)
return ConstantRange::getFull(BW);
CR = CR.unionWith(CI->getValue());
}
return CR;
}

static ConstantRange toConstantRange(const ValueLatticeElement &Val,
Type *Ty, bool UndefAllowed = false) {
assert(Ty->isIntOrIntVectorTy() && "Must be integer type");
Expand All @@ -844,6 +862,9 @@ static ConstantRange toConstantRange(const ValueLatticeElement &Val,
unsigned BW = Ty->getScalarSizeInBits();
if (Val.isUnknown())
return ConstantRange::getEmpty(BW);
if (Val.isConstant())
if (auto *VTy = dyn_cast<FixedVectorType>(Ty))
return getConstantRangeFromVector(Val.getConstant(), VTy);
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Suggested change
if (Val.isConstant())
if (auto *VTy = dyn_cast<FixedVectorType>(Ty))
return getConstantRangeFromVector(Val.getConstant(), VTy);
if (Val.isConstant()) {
if (auto *CI = dyn_cast_or_null<ConstantInt>(Val.getConstant()->getSplatValue(/*AllowPoison=*/true)))
return ConstantRange(CI->getValue());
if (auto *VTy = dyn_cast<FixedVectorType>(Ty))
return getConstantRangeFromVector(Val.getConstant(), VTy);
}

Do you have plan to support constant scalable vector splats?

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Good point. I've added scalable vectors support.

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What about just using computeConstantRange to do it?
AFAICT the only case they handle differently is poison elements.

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I don't want to use computeConstantRange() here, but extracting a common helper would make sense as a followup, as part of making computeConstantRange() handle poison elements.

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Ah looks like you beat me too it

return ConstantRange::getFull(BW);
}

Expand Down Expand Up @@ -968,7 +989,7 @@ LazyValueInfoImpl::solveBlockValueCast(CastInst *CI, BasicBlock *BB) {
return std::nullopt;
const ConstantRange &LHSRange = *LHSRes;

const unsigned ResultBitWidth = CI->getType()->getIntegerBitWidth();
const unsigned ResultBitWidth = CI->getType()->getScalarSizeInBits();

// NOTE: We're currently limited by the set of operations that ConstantRange
// can evaluate symbolically. Enhancing that set will allows us to analyze
Expand Down Expand Up @@ -1108,7 +1129,7 @@ LazyValueInfoImpl::getValueFromSimpleICmpCondition(CmpInst::Predicate Pred,
const APInt &Offset,
Instruction *CxtI,
bool UseBlockValue) {
ConstantRange RHSRange(RHS->getType()->getIntegerBitWidth(),
ConstantRange RHSRange(RHS->getType()->getScalarSizeInBits(),
/*isFullSet=*/true);
if (ConstantInt *CI = dyn_cast<ConstantInt>(RHS)) {
RHSRange = ConstantRange(CI->getValue());
Expand Down Expand Up @@ -1728,7 +1749,6 @@ Constant *LazyValueInfo::getConstant(Value *V, Instruction *CxtI) {

ConstantRange LazyValueInfo::getConstantRange(Value *V, Instruction *CxtI,
bool UndefAllowed) {
assert(V->getType()->isIntegerTy());
BasicBlock *BB = CxtI->getParent();
ValueLatticeElement Result =
getOrCreateImpl(BB->getModule()).getValueInBlock(V, BB, CxtI);
Expand Down
53 changes: 10 additions & 43 deletions llvm/lib/Transforms/Scalar/CorrelatedValuePropagation.cpp
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Original file line number Diff line number Diff line change
Expand Up @@ -288,9 +288,8 @@ static bool processPHI(PHINode *P, LazyValueInfo *LVI, DominatorTree *DT,
}

static bool processICmp(ICmpInst *Cmp, LazyValueInfo *LVI) {
// Only for signed relational comparisons of scalar integers.
if (Cmp->getType()->isVectorTy() ||
!Cmp->getOperand(0)->getType()->isIntegerTy())
// Only for signed relational comparisons of integers.
if (!Cmp->getOperand(0)->getType()->isIntOrIntVectorTy())
return false;

if (!Cmp->isSigned())
Expand Down Expand Up @@ -505,12 +504,8 @@ static bool processBinOp(BinaryOperator *BinOp, LazyValueInfo *LVI);
// because it is negation-invariant.
static bool processAbsIntrinsic(IntrinsicInst *II, LazyValueInfo *LVI) {
Value *X = II->getArgOperand(0);
Type *Ty = X->getType();
if (!Ty->isIntegerTy())
return false;

bool IsIntMinPoison = cast<ConstantInt>(II->getArgOperand(1))->isOne();
APInt IntMin = APInt::getSignedMinValue(Ty->getScalarSizeInBits());
APInt IntMin = APInt::getSignedMinValue(X->getType()->getScalarSizeInBits());
ConstantRange Range = LVI->getConstantRangeAtUse(
II->getOperandUse(0), /*UndefAllowed*/ IsIntMinPoison);

Expand Down Expand Up @@ -679,15 +674,13 @@ static bool processCallSite(CallBase &CB, LazyValueInfo *LVI) {
}

if (auto *WO = dyn_cast<WithOverflowInst>(&CB)) {
if (WO->getLHS()->getType()->isIntegerTy() && willNotOverflow(WO, LVI)) {
if (willNotOverflow(WO, LVI))
return processOverflowIntrinsic(WO, LVI);
}
}

if (auto *SI = dyn_cast<SaturatingInst>(&CB)) {
if (SI->getType()->isIntegerTy() && willNotOverflow(SI, LVI)) {
if (willNotOverflow(SI, LVI))
return processSaturatingInst(SI, LVI);
}
}

bool Changed = false;
Expand Down Expand Up @@ -761,11 +754,10 @@ static bool narrowSDivOrSRem(BinaryOperator *Instr, const ConstantRange &LCR,
const ConstantRange &RCR) {
assert(Instr->getOpcode() == Instruction::SDiv ||
Instr->getOpcode() == Instruction::SRem);
assert(!Instr->getType()->isVectorTy());

// Find the smallest power of two bitwidth that's sufficient to hold Instr's
// operands.
unsigned OrigWidth = Instr->getType()->getIntegerBitWidth();
unsigned OrigWidth = Instr->getType()->getScalarSizeInBits();

// What is the smallest bit width that can accommodate the entire value ranges
// of both of the operands?
Expand All @@ -788,7 +780,7 @@ static bool narrowSDivOrSRem(BinaryOperator *Instr, const ConstantRange &LCR,

++NumSDivSRemsNarrowed;
IRBuilder<> B{Instr};
auto *TruncTy = Type::getIntNTy(Instr->getContext(), NewWidth);
auto *TruncTy = Instr->getType()->getWithNewBitWidth(NewWidth);
auto *LHS = B.CreateTruncOrBitCast(Instr->getOperand(0), TruncTy,
Instr->getName() + ".lhs.trunc");
auto *RHS = B.CreateTruncOrBitCast(Instr->getOperand(1), TruncTy,
Expand All @@ -809,7 +801,6 @@ static bool expandUDivOrURem(BinaryOperator *Instr, const ConstantRange &XCR,
Type *Ty = Instr->getType();
assert(Instr->getOpcode() == Instruction::UDiv ||
Instr->getOpcode() == Instruction::URem);
assert(!Ty->isVectorTy());
bool IsRem = Instr->getOpcode() == Instruction::URem;

Value *X = Instr->getOperand(0);
Expand Down Expand Up @@ -892,7 +883,6 @@ static bool narrowUDivOrURem(BinaryOperator *Instr, const ConstantRange &XCR,
const ConstantRange &YCR) {
assert(Instr->getOpcode() == Instruction::UDiv ||
Instr->getOpcode() == Instruction::URem);
assert(!Instr->getType()->isVectorTy());

// Find the smallest power of two bitwidth that's sufficient to hold Instr's
// operands.
Expand All @@ -905,12 +895,12 @@ static bool narrowUDivOrURem(BinaryOperator *Instr, const ConstantRange &XCR,

// NewWidth might be greater than OrigWidth if OrigWidth is not a power of
// two.
if (NewWidth >= Instr->getType()->getIntegerBitWidth())
if (NewWidth >= Instr->getType()->getScalarSizeInBits())
return false;

++NumUDivURemsNarrowed;
IRBuilder<> B{Instr};
auto *TruncTy = Type::getIntNTy(Instr->getContext(), NewWidth);
auto *TruncTy = Instr->getType()->getWithNewBitWidth(NewWidth);
auto *LHS = B.CreateTruncOrBitCast(Instr->getOperand(0), TruncTy,
Instr->getName() + ".lhs.trunc");
auto *RHS = B.CreateTruncOrBitCast(Instr->getOperand(1), TruncTy,
Expand All @@ -929,9 +919,6 @@ static bool narrowUDivOrURem(BinaryOperator *Instr, const ConstantRange &XCR,
static bool processUDivOrURem(BinaryOperator *Instr, LazyValueInfo *LVI) {
assert(Instr->getOpcode() == Instruction::UDiv ||
Instr->getOpcode() == Instruction::URem);
if (Instr->getType()->isVectorTy())
return false;

ConstantRange XCR = LVI->getConstantRangeAtUse(Instr->getOperandUse(0),
/*UndefAllowed*/ false);
// Allow undef for RHS, as we can assume it is division by zero UB.
Expand All @@ -946,7 +933,6 @@ static bool processUDivOrURem(BinaryOperator *Instr, LazyValueInfo *LVI) {
static bool processSRem(BinaryOperator *SDI, const ConstantRange &LCR,
const ConstantRange &RCR, LazyValueInfo *LVI) {
assert(SDI->getOpcode() == Instruction::SRem);
assert(!SDI->getType()->isVectorTy());

if (LCR.abs().icmp(CmpInst::ICMP_ULT, RCR.abs())) {
SDI->replaceAllUsesWith(SDI->getOperand(0));
Expand Down Expand Up @@ -1006,7 +992,6 @@ static bool processSRem(BinaryOperator *SDI, const ConstantRange &LCR,
static bool processSDiv(BinaryOperator *SDI, const ConstantRange &LCR,
const ConstantRange &RCR, LazyValueInfo *LVI) {
assert(SDI->getOpcode() == Instruction::SDiv);
assert(!SDI->getType()->isVectorTy());

// Check whether the division folds to a constant.
ConstantRange DivCR = LCR.sdiv(RCR);
Expand Down Expand Up @@ -1064,9 +1049,6 @@ static bool processSDiv(BinaryOperator *SDI, const ConstantRange &LCR,
static bool processSDivOrSRem(BinaryOperator *Instr, LazyValueInfo *LVI) {
assert(Instr->getOpcode() == Instruction::SDiv ||
Instr->getOpcode() == Instruction::SRem);
if (Instr->getType()->isVectorTy())
return false;

ConstantRange LCR =
LVI->getConstantRangeAtUse(Instr->getOperandUse(0), /*AllowUndef*/ false);
// Allow undef for RHS, as we can assume it is division by zero UB.
Expand All @@ -1085,12 +1067,9 @@ static bool processSDivOrSRem(BinaryOperator *Instr, LazyValueInfo *LVI) {
}

static bool processAShr(BinaryOperator *SDI, LazyValueInfo *LVI) {
if (SDI->getType()->isVectorTy())
return false;

ConstantRange LRange =
LVI->getConstantRangeAtUse(SDI->getOperandUse(0), /*UndefAllowed*/ false);
unsigned OrigWidth = SDI->getType()->getIntegerBitWidth();
unsigned OrigWidth = SDI->getType()->getScalarSizeInBits();
ConstantRange NegOneOrZero =
ConstantRange(APInt(OrigWidth, (uint64_t)-1, true), APInt(OrigWidth, 1));
if (NegOneOrZero.contains(LRange)) {
Expand All @@ -1117,9 +1096,6 @@ static bool processAShr(BinaryOperator *SDI, LazyValueInfo *LVI) {
}

static bool processSExt(SExtInst *SDI, LazyValueInfo *LVI) {
if (SDI->getType()->isVectorTy())
return false;

const Use &Base = SDI->getOperandUse(0);
if (!LVI->getConstantRangeAtUse(Base, /*UndefAllowed*/ false)
.isAllNonNegative())
Expand All @@ -1138,9 +1114,6 @@ static bool processSExt(SExtInst *SDI, LazyValueInfo *LVI) {
}

static bool processPossibleNonNeg(PossiblyNonNegInst *I, LazyValueInfo *LVI) {
if (I->getType()->isVectorTy())
return false;

if (I->hasNonNeg())
return false;

Expand All @@ -1164,9 +1137,6 @@ static bool processUIToFP(UIToFPInst *UIToFP, LazyValueInfo *LVI) {
}

static bool processSIToFP(SIToFPInst *SIToFP, LazyValueInfo *LVI) {
if (SIToFP->getType()->isVectorTy())
return false;

const Use &Base = SIToFP->getOperandUse(0);
if (!LVI->getConstantRangeAtUse(Base, /*UndefAllowed*/ false)
.isAllNonNegative())
Expand All @@ -1187,9 +1157,6 @@ static bool processSIToFP(SIToFPInst *SIToFP, LazyValueInfo *LVI) {
static bool processBinOp(BinaryOperator *BinOp, LazyValueInfo *LVI) {
using OBO = OverflowingBinaryOperator;

if (BinOp->getType()->isVectorTy())
return false;

bool NSW = BinOp->hasNoSignedWrap();
bool NUW = BinOp->hasNoUnsignedWrap();
if (NSW && NUW)
Expand Down
4 changes: 1 addition & 3 deletions llvm/test/Transforms/CorrelatedValuePropagation/icmp.ll
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Expand Up @@ -1246,13 +1246,11 @@ define i1 @non_const_range_minmax(i8 %a, i8 %b) {
ret i1 %cmp1
}

; FIXME: Also support vectors.
define <2 x i1> @non_const_range_minmax_vec(<2 x i8> %a, <2 x i8> %b) {
; CHECK-LABEL: @non_const_range_minmax_vec(
; CHECK-NEXT: [[A2:%.*]] = call <2 x i8> @llvm.umin.v2i8(<2 x i8> [[A:%.*]], <2 x i8> <i8 10, i8 10>)
; CHECK-NEXT: [[B2:%.*]] = call <2 x i8> @llvm.umax.v2i8(<2 x i8> [[B:%.*]], <2 x i8> <i8 11, i8 11>)
; CHECK-NEXT: [[CMP1:%.*]] = icmp ult <2 x i8> [[A2]], [[B2]]
; CHECK-NEXT: ret <2 x i1> [[CMP1]]
; CHECK-NEXT: ret <2 x i1> <i1 true, i1 true>
;
%a2 = call <2 x i8> @llvm.umin.v2i8(<2 x i8> %a, <2 x i8> <i8 10, i8 10>)
%b2 = call <2 x i8> @llvm.umax.v2i8(<2 x i8> %b, <2 x i8> <i8 11, i8 11>)
Expand Down
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