diff options
Diffstat (limited to 'contrib/llvm-project/llvm/lib/Analysis/InstructionSimplify.cpp')
| -rw-r--r-- | contrib/llvm-project/llvm/lib/Analysis/InstructionSimplify.cpp | 21 |
1 files changed, 8 insertions, 13 deletions
diff --git a/contrib/llvm-project/llvm/lib/Analysis/InstructionSimplify.cpp b/contrib/llvm-project/llvm/lib/Analysis/InstructionSimplify.cpp index 4775340b3438..60895d3ced1a 100644 --- a/contrib/llvm-project/llvm/lib/Analysis/InstructionSimplify.cpp +++ b/contrib/llvm-project/llvm/lib/Analysis/InstructionSimplify.cpp @@ -2588,8 +2588,14 @@ computePointerICmp(CmpInst::Predicate Pred, Value *LHS, Value *RHS, // numerous hazards. AliasAnalysis and its utilities rely on special rules // governing loads and stores which don't apply to icmps. Also, AliasAnalysis // doesn't need to guarantee pointer inequality when it says NoAlias. - Constant *LHSOffset = stripAndComputeConstantOffsets(DL, LHS); - Constant *RHSOffset = stripAndComputeConstantOffsets(DL, RHS); + + // Even if an non-inbounds GEP occurs along the path we can still optimize + // equality comparisons concerning the result. + bool AllowNonInbounds = ICmpInst::isEquality(Pred); + Constant *LHSOffset = + stripAndComputeConstantOffsets(DL, LHS, AllowNonInbounds); + Constant *RHSOffset = + stripAndComputeConstantOffsets(DL, RHS, AllowNonInbounds); // If LHS and RHS are related via constant offsets to the same base // value, we can replace it with an icmp which just compares the offsets. @@ -2659,17 +2665,6 @@ computePointerICmp(CmpInst::Predicate Pred, Value *LHS, Value *RHS, !CmpInst::isTrueWhenEqual(Pred)); } - // Even if an non-inbounds GEP occurs along the path we can still optimize - // equality comparisons concerning the result. We avoid walking the whole - // chain again by starting where the last calls to - // stripAndComputeConstantOffsets left off and accumulate the offsets. - Constant *LHSNoBound = stripAndComputeConstantOffsets(DL, LHS, true); - Constant *RHSNoBound = stripAndComputeConstantOffsets(DL, RHS, true); - if (LHS == RHS) - return ConstantExpr::getICmp(Pred, - ConstantExpr::getAdd(LHSOffset, LHSNoBound), - ConstantExpr::getAdd(RHSOffset, RHSNoBound)); - // If one side of the equality comparison must come from a noalias call // (meaning a system memory allocation function), and the other side must // come from a pointer that cannot overlap with dynamically-allocated |