diff options
Diffstat (limited to 'llvm/lib/Analysis')
| -rw-r--r-- | llvm/lib/Analysis/InstructionSimplify.cpp | 9 |
1 files changed, 7 insertions, 2 deletions
diff --git a/llvm/lib/Analysis/InstructionSimplify.cpp b/llvm/lib/Analysis/InstructionSimplify.cpp index 0cb0982d311..d90f14a13fa 100644 --- a/llvm/lib/Analysis/InstructionSimplify.cpp +++ b/llvm/lib/Analysis/InstructionSimplify.cpp @@ -3054,8 +3054,13 @@ static Value *SimplifyFCmpInst(unsigned Predicate, Value *LHS, Value *RHS, if (Pred == FCmpInst::FCMP_TRUE) return ConstantInt::get(GetCompareTy(LHS), 1); - if (isa<UndefValue>(RHS)) // fcmp pred X, undef -> undef - return UndefValue::get(GetCompareTy(LHS)); + // fcmp pred x, undef and fcmp pred undef, x + // fold to true if unordered, false if ordered + if (isa<UndefValue>(LHS) || isa<UndefValue>(RHS)) { + // Choosing NaN for the undef will always make unordered comparison succeed + // and ordered comparison fail. + return ConstantInt::get(GetCompareTy(LHS), CmpInst::isUnordered(Pred)); + } // fcmp x,x -> true/false. Not all compares are foldable. if (LHS == RHS) { |
