diff options
| -rw-r--r-- | llvm/lib/Transforms/InstCombine/InstCombineMulDivRem.cpp | 42 |
1 files changed, 18 insertions, 24 deletions
diff --git a/llvm/lib/Transforms/InstCombine/InstCombineMulDivRem.cpp b/llvm/lib/Transforms/InstCombine/InstCombineMulDivRem.cpp index 69993ea8347..cb48b93473e 100644 --- a/llvm/lib/Transforms/InstCombine/InstCombineMulDivRem.cpp +++ b/llvm/lib/Transforms/InstCombine/InstCombineMulDivRem.cpp @@ -560,6 +560,11 @@ Instruction *InstCombiner::visitFMul(BinaryOperator &I) { if (Instruction *FoldedMul = foldOpWithConstantIntoOperand(I)) return FoldedMul; + // -X * C --> X * -C + Value *X; + if (match(Op0, m_FNeg(m_Value(X)))) + return BinaryOperator::CreateFMulFMF(X, ConstantExpr::getFNeg(C), &I); + // (fmul X, -1.0) --> (fsub -0.0, X) if (match(C, m_SpecificFP(-1.0))) { Constant *NegZero = ConstantFP::getNegativeZero(Op1->getType()); @@ -673,34 +678,23 @@ Instruction *InstCombiner::visitFMul(BinaryOperator &I) { } } + // -X * -Y --> X * Y + Value *X, *Y; + if (match(Op0, m_FNeg(m_Value(X))) && match(Op1, m_FNeg(m_Value(Y)))) + return BinaryOperator::CreateFMulFMF(X, Y, &I); + + // Sink negation: -X * Y --> -(X * Y) + if (match(Op0, m_OneUse(m_FNeg(m_Value(X))))) + return BinaryOperator::CreateFNegFMF(Builder.CreateFMulFMF(X, Op1, &I), &I); + + // Sink negation: Y * -X --> -(X * Y) + if (match(Op1, m_OneUse(m_FNeg(m_Value(X))))) + return BinaryOperator::CreateFNegFMF(Builder.CreateFMulFMF(X, Op0, &I), &I); + // Handle symmetric situation in a 2-iteration loop Value *Opnd0 = Op0; Value *Opnd1 = Op1; for (int i = 0; i < 2; i++) { - bool IgnoreZeroSign = I.hasNoSignedZeros(); - if (BinaryOperator::isFNeg(Opnd0, IgnoreZeroSign)) { - BuilderTy::FastMathFlagGuard Guard(Builder); - Builder.setFastMathFlags(I.getFastMathFlags()); - - Value *N0 = dyn_castFNegVal(Opnd0, IgnoreZeroSign); - Value *N1 = dyn_castFNegVal(Opnd1, IgnoreZeroSign); - - // -X * -Y => X*Y - if (N1) { - Value *FMul = Builder.CreateFMul(N0, N1); - FMul->takeName(&I); - return replaceInstUsesWith(I, FMul); - } - - if (Opnd0->hasOneUse()) { - // -X * Y => -(X*Y) (Promote negation as high as possible) - Value *T = Builder.CreateFMul(N0, Opnd1); - Value *Neg = Builder.CreateFNeg(T); - Neg->takeName(&I); - return replaceInstUsesWith(I, Neg); - } - } - // Handle specials cases for FMul with selects feeding the operation if (Value *V = SimplifySelectsFeedingBinaryOp(I, Op0, Op1)) return replaceInstUsesWith(I, V); |
