diff options
Diffstat (limited to 'llvm/lib/Transforms/InstCombine/InstCombineAddSub.cpp')
| -rw-r--r-- | llvm/lib/Transforms/InstCombine/InstCombineAddSub.cpp | 5 |
1 files changed, 5 insertions, 0 deletions
diff --git a/llvm/lib/Transforms/InstCombine/InstCombineAddSub.cpp b/llvm/lib/Transforms/InstCombine/InstCombineAddSub.cpp index f3fe09f1cb0..8b355dcd1b2 100644 --- a/llvm/lib/Transforms/InstCombine/InstCombineAddSub.cpp +++ b/llvm/lib/Transforms/InstCombine/InstCombineAddSub.cpp @@ -1911,6 +1911,11 @@ Instruction *InstCombiner::visitFSub(BinaryOperator &I) { if (match(Op0, m_FSub(m_Specific(Op1), m_Value(X)))) return BinaryOperator::CreateFNegFMF(X, &I); + // Y - (X + Y) --> -X + // Y - (Y + X) --> -X + if (match(Op1, m_c_FAdd(m_Specific(Op0), m_Value(X)))) + return BinaryOperator::CreateFNegFMF(X, &I); + // TODO: This performs reassociative folds for FP ops. Some fraction of the // functionality has been subsumed by simple pattern matching here and in // InstSimplify. We should let a dedicated reassociation pass handle more |
