[llvm] r369421 - [InstCombine] add helper function for icmp+zext/sext; NFC
Sanjay Patel via llvm-commits
llvm-commits at lists.llvm.org
Tue Aug 20 11:15:17 PDT 2019
Author: spatel
Date: Tue Aug 20 11:15:17 2019
New Revision: 369421
URL: http://llvm.org/viewvc/llvm-project?rev=369421&view=rev
Log:
[InstCombine] add helper function for icmp+zext/sext; NFC
Modified:
llvm/trunk/lib/Transforms/InstCombine/InstCombineCompares.cpp
Modified: llvm/trunk/lib/Transforms/InstCombine/InstCombineCompares.cpp
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/Transforms/InstCombine/InstCombineCompares.cpp?rev=369421&r1=369420&r2=369421&view=diff
==============================================================================
--- llvm/trunk/lib/Transforms/InstCombine/InstCombineCompares.cpp (original)
+++ llvm/trunk/lib/Transforms/InstCombine/InstCombineCompares.cpp Tue Aug 20 11:15:17 2019
@@ -4026,103 +4026,66 @@ Instruction *InstCombiner::foldICmpEqual
return nullptr;
}
-/// Handle icmp (cast x), (cast or constant).
-Instruction *InstCombiner::foldICmpWithCastOp(ICmpInst &ICmp) {
- auto *CastOp0 = dyn_cast<CastInst>(ICmp.getOperand(0));
- if (!CastOp0)
- return nullptr;
- if (!isa<Constant>(ICmp.getOperand(1)) && !isa<CastInst>(ICmp.getOperand(1)))
+static Instruction *foldICmpWithZextOrSext(ICmpInst &ICmp) {
+ assert(isa<CastInst>(ICmp.getOperand(0)) && "Expected cast for operand 0");
+ auto *CastOp0 = cast<CastInst>(ICmp.getOperand(0));
+ Value *X;
+ if (!match(CastOp0, m_ZExtOrSExt(m_Value(X))))
return nullptr;
- Value *Op0Src = CastOp0->getOperand(0);
- Type *SrcTy = CastOp0->getSrcTy();
- Type *DestTy = CastOp0->getDestTy();
-
- // Turn icmp (ptrtoint x), (ptrtoint/c) into a compare of the input if the
- // integer type is the same size as the pointer type.
- auto CompatibleSizes = [&](Type *SrcTy, Type *DestTy) {
- if (isa<VectorType>(SrcTy)) {
- SrcTy = cast<VectorType>(SrcTy)->getElementType();
- DestTy = cast<VectorType>(DestTy)->getElementType();
- }
- return DL.getPointerTypeSizeInBits(SrcTy) == DestTy->getIntegerBitWidth();
- };
- if (CastOp0->getOpcode() == Instruction::PtrToInt &&
- CompatibleSizes(SrcTy, DestTy)) {
- Value *NewOp1 = nullptr;
- if (auto *PtrToIntOp1 = dyn_cast<PtrToIntOperator>(ICmp.getOperand(1))) {
- Value *PtrSrc = PtrToIntOp1->getOperand(0);
- if (PtrSrc->getType()->getPointerAddressSpace() ==
- Op0Src->getType()->getPointerAddressSpace()) {
- NewOp1 = PtrToIntOp1->getOperand(0);
- // If the pointer types don't match, insert a bitcast.
- if (Op0Src->getType() != NewOp1->getType())
- NewOp1 = Builder.CreateBitCast(NewOp1, Op0Src->getType());
- }
- } else if (auto *RHSC = dyn_cast<Constant>(ICmp.getOperand(1))) {
- NewOp1 = ConstantExpr::getIntToPtr(RHSC, SrcTy);
- }
-
- if (NewOp1)
- return new ICmpInst(ICmp.getPredicate(), Op0Src, NewOp1);
- }
-
- // The code below only handles extension cast instructions, so far.
- // Enforce this.
- if (CastOp0->getOpcode() != Instruction::ZExt &&
- CastOp0->getOpcode() != Instruction::SExt)
- return nullptr;
-
- bool isSignedExt = CastOp0->getOpcode() == Instruction::SExt;
- bool isSignedCmp = ICmp.isSigned();
-
+ bool IsSignedExt = CastOp0->getOpcode() == Instruction::SExt;
+ bool IsSignedCmp = ICmp.isSigned();
if (auto *CastOp1 = dyn_cast<CastInst>(ICmp.getOperand(1))) {
- // Not an extension from the same type?
- Value *Op1Src = CastOp1->getOperand(0);
- if (Op1Src->getType() != Op0Src->getType())
- return nullptr;
-
// If the signedness of the two casts doesn't agree (i.e. one is a sext
// and the other is a zext), then we can't handle this.
- if (CastOp1->getOpcode() != CastOp0->getOpcode())
+ if (CastOp0->getOpcode() != CastOp1->getOpcode())
return nullptr;
- // Deal with equality cases early.
+ // Not an extension from the same type?
+ // TODO: Handle this by extending the narrower operand to the type of
+ // the wider operand.
+ Value *Y = CastOp1->getOperand(0);
+ if (X->getType() != Y->getType())
+ return nullptr;
+
+ // (zext X) == (zext Y) --> X == Y
+ // (sext X) == (sext Y) --> X == Y
if (ICmp.isEquality())
- return new ICmpInst(ICmp.getPredicate(), Op0Src, Op1Src);
+ return new ICmpInst(ICmp.getPredicate(), X, Y);
// A signed comparison of sign extended values simplifies into a
// signed comparison.
- if (isSignedCmp && isSignedExt)
- return new ICmpInst(ICmp.getPredicate(), Op0Src, Op1Src);
+ if (IsSignedCmp && IsSignedExt)
+ return new ICmpInst(ICmp.getPredicate(), X, Y);
// The other three cases all fold into an unsigned comparison.
- return new ICmpInst(ICmp.getUnsignedPredicate(), Op0Src, Op1Src);
+ return new ICmpInst(ICmp.getUnsignedPredicate(), X, Y);
}
- // If we aren't dealing with a constant on the RHS, exit early.
+ // Below here, we are only folding a compare with constant.
auto *C = dyn_cast<Constant>(ICmp.getOperand(1));
if (!C)
return nullptr;
// Compute the constant that would happen if we truncated to SrcTy then
// re-extended to DestTy.
+ Type *SrcTy = CastOp0->getSrcTy();
+ Type *DestTy = CastOp0->getDestTy();
Constant *Res1 = ConstantExpr::getTrunc(C, SrcTy);
Constant *Res2 = ConstantExpr::getCast(CastOp0->getOpcode(), Res1, DestTy);
// If the re-extended constant didn't change...
if (Res2 == C) {
- // Deal with equality cases early.
if (ICmp.isEquality())
- return new ICmpInst(ICmp.getPredicate(), Op0Src, Res1);
+ return new ICmpInst(ICmp.getPredicate(), X, Res1);
// A signed comparison of sign extended values simplifies into a
// signed comparison.
- if (isSignedExt && isSignedCmp)
- return new ICmpInst(ICmp.getPredicate(), Op0Src, Res1);
+ if (IsSignedExt && IsSignedCmp)
+ return new ICmpInst(ICmp.getPredicate(), X, Res1);
// The other three cases all fold into an unsigned comparison.
- return new ICmpInst(ICmp.getUnsignedPredicate(), Op0Src, Res1);
+ return new ICmpInst(ICmp.getUnsignedPredicate(), X, Res1);
}
// The re-extended constant changed, partly changed (in the case of a vector),
@@ -4130,19 +4093,62 @@ Instruction *InstCombiner::foldICmpWithC
// expression), so the constant cannot be represented in the shorter type.
// All the cases that fold to true or false will have already been handled
// by SimplifyICmpInst, so only deal with the tricky case.
- if (isSignedCmp || !isSignedExt || !isa<ConstantInt>(C))
+ if (IsSignedCmp || !IsSignedExt || !isa<ConstantInt>(C))
return nullptr;
// Is source op positive?
// icmp ult (sext X), C --> icmp sgt X, -1
if (ICmp.getPredicate() == ICmpInst::ICMP_ULT)
- return new ICmpInst(CmpInst::ICMP_SGT, Op0Src,
- Constant::getAllOnesValue(SrcTy));
+ return new ICmpInst(CmpInst::ICMP_SGT, X, Constant::getAllOnesValue(SrcTy));
// Is source op negative?
// icmp ugt (sext X), C --> icmp slt X, 0
assert(ICmp.getPredicate() == ICmpInst::ICMP_UGT && "ICmp should be folded!");
- return new ICmpInst(CmpInst::ICMP_SLT, Op0Src, Constant::getNullValue(SrcTy));
+ return new ICmpInst(CmpInst::ICMP_SLT, X, Constant::getNullValue(SrcTy));
+}
+
+/// Handle icmp (cast x), (cast or constant).
+Instruction *InstCombiner::foldICmpWithCastOp(ICmpInst &ICmp) {
+ auto *CastOp0 = dyn_cast<CastInst>(ICmp.getOperand(0));
+ if (!CastOp0)
+ return nullptr;
+ if (!isa<Constant>(ICmp.getOperand(1)) && !isa<CastInst>(ICmp.getOperand(1)))
+ return nullptr;
+
+ Value *Op0Src = CastOp0->getOperand(0);
+ Type *SrcTy = CastOp0->getSrcTy();
+ Type *DestTy = CastOp0->getDestTy();
+
+ // Turn icmp (ptrtoint x), (ptrtoint/c) into a compare of the input if the
+ // integer type is the same size as the pointer type.
+ auto CompatibleSizes = [&](Type *SrcTy, Type *DestTy) {
+ if (isa<VectorType>(SrcTy)) {
+ SrcTy = cast<VectorType>(SrcTy)->getElementType();
+ DestTy = cast<VectorType>(DestTy)->getElementType();
+ }
+ return DL.getPointerTypeSizeInBits(SrcTy) == DestTy->getIntegerBitWidth();
+ };
+ if (CastOp0->getOpcode() == Instruction::PtrToInt &&
+ CompatibleSizes(SrcTy, DestTy)) {
+ Value *NewOp1 = nullptr;
+ if (auto *PtrToIntOp1 = dyn_cast<PtrToIntOperator>(ICmp.getOperand(1))) {
+ Value *PtrSrc = PtrToIntOp1->getOperand(0);
+ if (PtrSrc->getType()->getPointerAddressSpace() ==
+ Op0Src->getType()->getPointerAddressSpace()) {
+ NewOp1 = PtrToIntOp1->getOperand(0);
+ // If the pointer types don't match, insert a bitcast.
+ if (Op0Src->getType() != NewOp1->getType())
+ NewOp1 = Builder.CreateBitCast(NewOp1, Op0Src->getType());
+ }
+ } else if (auto *RHSC = dyn_cast<Constant>(ICmp.getOperand(1))) {
+ NewOp1 = ConstantExpr::getIntToPtr(RHSC, SrcTy);
+ }
+
+ if (NewOp1)
+ return new ICmpInst(ICmp.getPredicate(), Op0Src, NewOp1);
+ }
+
+ return foldICmpWithZextOrSext(ICmp);
}
static bool isNeutralValue(Instruction::BinaryOps BinaryOp, Value *RHS) {
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