diff options
Diffstat (limited to 'llvm/lib/Transforms')
| -rw-r--r-- | llvm/lib/Transforms/InstCombine/InstCombineAddSub.cpp | 16 |
1 files changed, 13 insertions, 3 deletions
diff --git a/llvm/lib/Transforms/InstCombine/InstCombineAddSub.cpp b/llvm/lib/Transforms/InstCombine/InstCombineAddSub.cpp index 2e0d3bf..2ed616f 100644 --- a/llvm/lib/Transforms/InstCombine/InstCombineAddSub.cpp +++ b/llvm/lib/Transforms/InstCombine/InstCombineAddSub.cpp @@ -2143,9 +2143,19 @@ static Instruction *foldFNegIntoConstant(Instruction &I) { if (match(FNegOp, m_FDiv(m_Value(X), m_Constant(C)))) return BinaryOperator::CreateFDivFMF(X, ConstantExpr::getFNeg(C), &I); // -(C / X) --> (-C) / X - if (match(FNegOp, m_FDiv(m_Constant(C), m_Value(X)))) - return BinaryOperator::CreateFDivFMF(ConstantExpr::getFNeg(C), X, &I); - + if (match(FNegOp, m_FDiv(m_Constant(C), m_Value(X)))) { + Instruction *FDiv = + BinaryOperator::CreateFDivFMF(ConstantExpr::getFNeg(C), X, &I); + + // Intersect 'nsz' and 'ninf' because those special value exceptions may not + // apply to the fdiv. Everything else propagates from the fneg. + // TODO: We could propagate nsz/ninf from fdiv alone? + FastMathFlags FMF = I.getFastMathFlags(); + FastMathFlags OpFMF = FNegOp->getFastMathFlags(); + FDiv->setHasNoSignedZeros(FMF.noSignedZeros() & OpFMF.noSignedZeros()); + FDiv->setHasNoInfs(FMF.noInfs() & OpFMF.noInfs()); + return FDiv; + } // With NSZ [ counter-example with -0.0: -(-0.0 + 0.0) != 0.0 + -0.0 ]: // -(X + C) --> -X + -C --> -C - X if (I.hasNoSignedZeros() && match(FNegOp, m_FAdd(m_Value(X), m_Constant(C)))) |