diff options
Diffstat (limited to 'llvm/lib/Analysis/ValueTracking.cpp')
| -rw-r--r-- | llvm/lib/Analysis/ValueTracking.cpp | 22 |
1 files changed, 17 insertions, 5 deletions
diff --git a/llvm/lib/Analysis/ValueTracking.cpp b/llvm/lib/Analysis/ValueTracking.cpp index 352b0fbd4dc..7de719579ad 100644 --- a/llvm/lib/Analysis/ValueTracking.cpp +++ b/llvm/lib/Analysis/ValueTracking.cpp @@ -3750,14 +3750,26 @@ static SelectPatternResult matchSelectPattern(CmpInst::Predicate Pred, return {SPF_UNKNOWN, SPNB_NA, false}; } -static Constant *lookThroughCast(CmpInst *CmpI, Value *V1, Value *V2, - Instruction::CastOps *CastOp) { +static Value *lookThroughCast(CmpInst *CmpI, Value *V1, Value *V2, + Instruction::CastOps *CastOp) { CastInst *CI = dyn_cast<CastInst>(V1); Constant *C = dyn_cast<Constant>(V2); - if (!CI || !C) + CastInst *CI2 = dyn_cast<CastInst>(V2); + if (!CI) return nullptr; *CastOp = CI->getOpcode(); + if (CI2) { + // If V1 and V2 are both the same cast from the same type, we can look + // through V1. + if (CI2->getOpcode() == CI->getOpcode() && + CI2->getSrcTy() == CI->getSrcTy()) + return CI2->getOperand(0); + return nullptr; + } else if (!C) { + return nullptr; + } + if (isa<SExtInst>(CI) && CmpI->isSigned()) { Constant *T = ConstantExpr::getTrunc(C, CI->getSrcTy()); // This is only valid if the truncated value can be sign-extended @@ -3817,11 +3829,11 @@ SelectPatternResult llvm::matchSelectPattern(Value *V, // Deal with type mismatches. if (CastOp && CmpLHS->getType() != TrueVal->getType()) { - if (Constant *C = lookThroughCast(CmpI, TrueVal, FalseVal, CastOp)) + if (Value *C = lookThroughCast(CmpI, TrueVal, FalseVal, CastOp)) return ::matchSelectPattern(Pred, FMF, CmpLHS, CmpRHS, cast<CastInst>(TrueVal)->getOperand(0), C, LHS, RHS); - if (Constant *C = lookThroughCast(CmpI, FalseVal, TrueVal, CastOp)) + if (Value *C = lookThroughCast(CmpI, FalseVal, TrueVal, CastOp)) return ::matchSelectPattern(Pred, FMF, CmpLHS, CmpRHS, C, cast<CastInst>(FalseVal)->getOperand(0), LHS, RHS); |
