diff options
| author | Chris Lattner <sabre@nondot.org> | 2010-03-03 19:46:03 +0000 |
|---|---|---|
| committer | Chris Lattner <sabre@nondot.org> | 2010-03-03 19:46:03 +0000 |
| commit | c8e14b3d37b80abb6adb4b831af0452d9ecbf2b2 (patch) | |
| tree | 82f5c1caf2f2072cfb903e28fbde8df7b103e0c7 /lib/Analysis/InstructionSimplify.cpp | |
| parent | fec8657351346966e48f9248079e85602dc1f85d (diff) | |
fix incorrect folding of icmp with undef, PR6481.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@97659 91177308-0d34-0410-b5e6-96231b3b80d8
Diffstat (limited to 'lib/Analysis/InstructionSimplify.cpp')
| -rw-r--r-- | lib/Analysis/InstructionSimplify.cpp | 7 |
1 files changed, 3 insertions, 4 deletions
diff --git a/lib/Analysis/InstructionSimplify.cpp b/lib/Analysis/InstructionSimplify.cpp index 1f8053afe9..8288e96eb7 100644 --- a/lib/Analysis/InstructionSimplify.cpp +++ b/lib/Analysis/InstructionSimplify.cpp @@ -194,11 +194,10 @@ Value *llvm::SimplifyICmpInst(unsigned Predicate, Value *LHS, Value *RHS, const Type *ITy = GetCompareTy(LHS); // icmp X, X -> true/false - if (LHS == RHS) + // X icmp undef -> true/false. For example, icmp ugt %X, undef -> false + // because X could be 0. + if (LHS == RHS || isa<UndefValue>(RHS)) return ConstantInt::get(ITy, CmpInst::isTrueWhenEqual(Pred)); - - if (isa<UndefValue>(RHS)) // X icmp undef -> undef - return UndefValue::get(ITy); // icmp <global/alloca*/null>, <global/alloca*/null> - Global/Stack value // addresses never equal each other! We already know that Op0 != Op1. |