diff options
| -rw-r--r-- | lib/Transforms/InstCombine/InstCombineAddSub.cpp | 15 | ||||
| -rw-r--r-- | test/Transforms/InstCombine/fneg-ext.ll | 11 |
2 files changed, 22 insertions, 4 deletions
diff --git a/lib/Transforms/InstCombine/InstCombineAddSub.cpp b/lib/Transforms/InstCombine/InstCombineAddSub.cpp index 1fa6897ddd..534feb8fad 100644 --- a/lib/Transforms/InstCombine/InstCombineAddSub.cpp +++ b/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<FPTruncInst>(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<FPExtInst>(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; } } diff --git a/test/Transforms/InstCombine/fneg-ext.ll b/test/Transforms/InstCombine/fneg-ext.ll index 49ad232526..922d26a465 100644 --- a/test/Transforms/InstCombine/fneg-ext.ll +++ b/test/Transforms/InstCombine/fneg-ext.ll @@ -10,3 +10,14 @@ define double @test1(float %a, double %b) nounwind readnone ssp uwtable { %3 = fsub double %b, %2 ret double %3 } + +; CHECK: test2 +define double @test2(float %a, double %b) nounwind readnone ssp uwtable { +; CHECK-NOT: fsub +; CHECK: fpext +; CHECK: fadd fast + %1 = fsub float -0.000000e+00, %a + %2 = fpext float %1 to double + %3 = fsub fast double %b, %2 + ret double %3 +} |