diff options
Diffstat (limited to 'llvm/lib')
| -rw-r--r-- | llvm/lib/Transforms/InstCombine/InstCombineCompares.cpp | 9 |
1 files changed, 9 insertions, 0 deletions
diff --git a/llvm/lib/Transforms/InstCombine/InstCombineCompares.cpp b/llvm/lib/Transforms/InstCombine/InstCombineCompares.cpp index 12894b7833b..61e1d928a99 100644 --- a/llvm/lib/Transforms/InstCombine/InstCombineCompares.cpp +++ b/llvm/lib/Transforms/InstCombine/InstCombineCompares.cpp @@ -4506,7 +4506,16 @@ Instruction *InstCombiner::visitICmpInst(ICmpInst &I) { return New; } + // Sign-bit checks are preserved through signed floating-point casts: + // icmp slt (bitcast (sitofp X)), 0 --> icmp slt X, 0 + // icmp sgt (bitcast (sitofp X)), -1 --> icmp sgt X, -1 Value *X; + if (match(Op0, m_BitCast(m_SIToFP(m_Value(X))))) { + if (Pred == ICmpInst::ICMP_SLT && match(Op1, m_Zero())) + return new ICmpInst(Pred, X, ConstantInt::getNullValue(X->getType())); + if (Pred == ICmpInst::ICMP_SGT && match(Op1, m_AllOnes())) + return new ICmpInst(Pred, X, ConstantInt::getAllOnesValue(X->getType())); + } // Zero-equality checks are preserved through unsigned floating-point casts: // icmp eq (bitcast (uitofp X)), 0 --> icmp eq X, 0 |
