From c7be519dc004a51cbb2db1ab8c450eec9d2305eb Mon Sep 17 00:00:00 2001 From: Owen Anderson Date: Tue, 30 Jul 2013 23:53:17 +0000 Subject: Preserve fast-math flags when folding (fsub x, (fneg y)) to (fadd x, y). llvm-svn: 187462 --- llvm/lib/Transforms/InstCombine/InstCombineAddSub.cpp | 15 +++++++++++---- 1 file changed, 11 insertions(+), 4 deletions(-) (limited to 'llvm/lib/Transforms') diff --git a/llvm/lib/Transforms/InstCombine/InstCombineAddSub.cpp b/llvm/lib/Transforms/InstCombine/InstCombineAddSub.cpp index 1fa6897ddd2..534feb8fad2 100644 --- a/llvm/lib/Transforms/InstCombine/InstCombineAddSub.cpp +++ b/llvm/lib/Transforms/InstCombine/InstCombineAddSub.cpp @@ -1530,17 +1530,24 @@ Instruction *InstCombiner::visitFSub(BinaryOperator &I) { // If this is a 'B = x-(-A)', change to B = x+A, potentially looking // through FP extensions/truncations along the way. - if (Value *V = dyn_castFNegVal(Op1)) - return BinaryOperator::CreateFAdd(Op0, V); + if (Value *V = dyn_castFNegVal(Op1)) { + Instruction *NewI = BinaryOperator::CreateFAdd(Op0, V); + NewI->copyFastMathFlags(&I); + return NewI; + } if (FPTruncInst *FPTI = dyn_cast(Op1)) { if (Value *V = dyn_castFNegVal(FPTI->getOperand(0))) { Value *NewTrunc = Builder->CreateFPTrunc(V, I.getType()); - return BinaryOperator::CreateFAdd(Op0, NewTrunc); + Instruction *NewI = BinaryOperator::CreateFAdd(Op0, NewTrunc); + NewI->copyFastMathFlags(&I); + return NewI; } } else if (FPExtInst *FPEI = dyn_cast(Op1)) { if (Value *V = dyn_castFNegVal(FPEI->getOperand(0))) { Value *NewExt = Builder->CreateFPExt(V, I.getType()); - return BinaryOperator::CreateFAdd(Op0, NewExt); + Instruction *NewI = BinaryOperator::CreateFAdd(Op0, NewExt); + NewI->copyFastMathFlags(&I); + return NewI; } } -- cgit v1.2.3