From eeeffbb497e7611dc8445924bfe47c54c94b8c5c Mon Sep 17 00:00:00 2001 From: Nick Lewycky Date: Sat, 25 Feb 2012 20:19:07 +0000 Subject: An argument and a local identified object (eg. a noalias call) could turn out equal if both are null. In the test, scope type %t and global @y by adding a 'gep' prefix to them. llvm-svn: 151452 --- llvm/lib/Analysis/InstructionSimplify.cpp | 25 +++++++++++++------------ 1 file changed, 13 insertions(+), 12 deletions(-) (limited to 'llvm/lib/Analysis') diff --git a/llvm/lib/Analysis/InstructionSimplify.cpp b/llvm/lib/Analysis/InstructionSimplify.cpp index 11afa851597..93f55684c24 100644 --- a/llvm/lib/Analysis/InstructionSimplify.cpp +++ b/llvm/lib/Analysis/InstructionSimplify.cpp @@ -1626,21 +1626,22 @@ static Value *SimplifyICmpInst(unsigned Predicate, Value *LHS, Value *RHS, LHSPtr = stripPointerAdjustments(LHSPtr); if (llvm::isIdentifiedObject(LHSPtr)) { RHSPtr = stripPointerAdjustments(RHSPtr); - // If both sides are different identified objects, they aren't equal unless - // they're null. - if (LHSPtr != RHSPtr && llvm::isIdentifiedObject(RHSPtr) && - (llvm::isKnownNonNull(LHSPtr) || llvm::isKnownNonNull(RHSPtr))) - return ConstantInt::get(ITy, CmpInst::isFalseWhenEqual(Pred)); + if (llvm::isKnownNonNull(LHSPtr) || llvm::isKnownNonNull(RHSPtr)) { + // If both sides are different identified objects, they aren't equal + // unless they're null. + if (LHSPtr != RHSPtr && llvm::isIdentifiedObject(RHSPtr)) + return ConstantInt::get(ITy, CmpInst::isFalseWhenEqual(Pred)); + + // A local identified object (alloca or noalias call) can't equal any + // incoming argument, unless they're both null. + if ((isa(LHSPtr) && isa(RHSPtr)) || + (isa(RHSPtr) && isa(LHSPtr))) + return ConstantInt::get(ITy, CmpInst::isFalseWhenEqual(Pred)); + } - // Assume that the null is on the right. + // Assume that the constant null is on the right. if (llvm::isKnownNonNull(LHSPtr) && isa(RHSPtr)) return ConstantInt::get(ITy, CmpInst::isFalseWhenEqual(Pred)); - - // A local instruction (alloca or noalias call) can't equal any incoming - // argument. - if ((isa(LHSPtr) && isa(RHSPtr)) || - (isa(RHSPtr) && isa(LHSPtr))) - return ConstantInt::get(ITy, CmpInst::isFalseWhenEqual(Pred)); } // If we are comparing with zero then try hard since this is a common case. -- cgit v1.2.3