diff options
Diffstat (limited to 'llvm/lib/Transforms/InstCombine/InstCombineMulDivRem.cpp')
| -rw-r--r-- | llvm/lib/Transforms/InstCombine/InstCombineMulDivRem.cpp | 14 |
1 files changed, 12 insertions, 2 deletions
diff --git a/llvm/lib/Transforms/InstCombine/InstCombineMulDivRem.cpp b/llvm/lib/Transforms/InstCombine/InstCombineMulDivRem.cpp index 0b9128a9f5a1..2774e46151fa 100644 --- a/llvm/lib/Transforms/InstCombine/InstCombineMulDivRem.cpp +++ b/llvm/lib/Transforms/InstCombine/InstCombineMulDivRem.cpp @@ -1239,6 +1239,14 @@ Instruction *InstCombiner::visitFDiv(BinaryOperator &I) { Value *YZ = Builder.CreateFMulFMF(Y, Op0, &I); return BinaryOperator::CreateFDivFMF(YZ, X, &I); } + // Z / (1.0 / Y) => (Y * Z) + // + // This is a special case of Z / (X / Y) => (Y * Z) / X, with X = 1.0. The + // m_OneUse check is avoided because even in the case of the multiple uses + // for 1.0/Y, the number of instructions remain the same and a division is + // replaced by a multiplication. + if (match(Op1, m_FDiv(m_SpecificFP(1.0), m_Value(Y)))) + return BinaryOperator::CreateFMulFMF(Y, Op0, &I); } if (I.hasAllowReassoc() && Op0->hasOneUse() && Op1->hasOneUse()) { @@ -1368,8 +1376,10 @@ Instruction *InstCombiner::visitURem(BinaryOperator &I) { } // 1 urem X -> zext(X != 1) - if (match(Op0, m_One())) - return CastInst::CreateZExtOrBitCast(Builder.CreateICmpNE(Op1, Op0), Ty); + if (match(Op0, m_One())) { + Value *Cmp = Builder.CreateICmpNE(Op1, ConstantInt::get(Ty, 1)); + return CastInst::CreateZExtOrBitCast(Cmp, Ty); + } // X urem C -> X < C ? X : X - C, where C >= signbit. if (match(Op1, m_Negative())) { |