diff options
Diffstat (limited to 'lib/Analysis/InstructionSimplify.cpp')
| -rw-r--r-- | lib/Analysis/InstructionSimplify.cpp | 33 |
1 files changed, 29 insertions, 4 deletions
diff --git a/lib/Analysis/InstructionSimplify.cpp b/lib/Analysis/InstructionSimplify.cpp index b53ac13..8288e96 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. @@ -283,6 +282,32 @@ Value *llvm::SimplifyFCmpInst(unsigned Predicate, Value *LHS, Value *RHS, // True if unordered. return ConstantInt::getTrue(CFP->getContext()); } + // Check whether the constant is an infinity. + if (CFP->getValueAPF().isInfinity()) { + if (CFP->getValueAPF().isNegative()) { + switch (Pred) { + case FCmpInst::FCMP_OLT: + // No value is ordered and less than negative infinity. + return ConstantInt::getFalse(CFP->getContext()); + case FCmpInst::FCMP_UGE: + // All values are unordered with or at least negative infinity. + return ConstantInt::getTrue(CFP->getContext()); + default: + break; + } + } else { + switch (Pred) { + case FCmpInst::FCMP_OGT: + // No value is ordered and greater than infinity. + return ConstantInt::getFalse(CFP->getContext()); + case FCmpInst::FCMP_ULE: + // All values are unordered with and at most infinity. + return ConstantInt::getTrue(CFP->getContext()); + default: + break; + } + } + } } } |