From 66a82b966eaf2814dca4ee643d826aebc4d1be90 Mon Sep 17 00:00:00 2001 From: Stuart Hastings Date: Sat, 14 May 2011 05:55:10 +0000 Subject: Avoid combining GEPs that might overflow at runtime. rdar://problem/9267970 Patch by Julien Lerouge! llvm-svn: 131339 --- llvm/lib/Transforms/InstCombine/InstCombineCompares.cpp | 4 +++- 1 file changed, 3 insertions(+), 1 deletion(-) (limited to 'llvm/lib/Transforms') diff --git a/llvm/lib/Transforms/InstCombine/InstCombineCompares.cpp b/llvm/lib/Transforms/InstCombine/InstCombineCompares.cpp index b6963c54999..ede659b0111 100644 --- a/llvm/lib/Transforms/InstCombine/InstCombineCompares.cpp +++ b/llvm/lib/Transforms/InstCombine/InstCombineCompares.cpp @@ -634,6 +634,7 @@ Instruction *InstCombiner::FoldGEPICmp(GEPOperator *GEPLHS, Value *RHS, if (AllZeros) return FoldGEPICmp(GEPLHS, GEPRHS->getOperand(0), Cond, I); + bool GEPsInBounds = GEPLHS->isInBounds() && GEPRHS->isInBounds(); if (GEPLHS->getNumOperands() == GEPRHS->getNumOperands()) { // If the GEPs only differ by one index, compare it. unsigned NumDifferences = 0; // Keep track of # differences. @@ -656,7 +657,7 @@ Instruction *InstCombiner::FoldGEPICmp(GEPOperator *GEPLHS, Value *RHS, ConstantInt::get(Type::getInt1Ty(I.getContext()), ICmpInst::isTrueWhenEqual(Cond))); - else if (NumDifferences == 1) { + else if (NumDifferences == 1 && GEPsInBounds) { Value *LHSV = GEPLHS->getOperand(DiffOperand); Value *RHSV = GEPRHS->getOperand(DiffOperand); // Make sure we do a signed comparison here. @@ -667,6 +668,7 @@ Instruction *InstCombiner::FoldGEPICmp(GEPOperator *GEPLHS, Value *RHS, // Only lower this if the icmp is the only user of the GEP or if we expect // the result to fold to a constant! if (TD && + GEPsInBounds && (isa(GEPLHS) || GEPLHS->hasOneUse()) && (isa(GEPRHS) || GEPRHS->hasOneUse())) { // ((gep Ptr, OFFSET1) cmp (gep Ptr, OFFSET2) ---> (OFFSET1 cmp OFFSET2) -- cgit v1.2.3