From 228680ded8bbd04dd179e953843f86c44e982448 Mon Sep 17 00:00:00 2001 From: Benjamin Kramer Date: Sun, 14 Jun 2015 21:01:20 +0000 Subject: [PATCH] [InstSimplify] fsub nnan x, x -> 0.0 is valid without ninf Both inf - inf and (-inf) - (-inf) are NaN, so it's already covered by nnan. llvm-svn: 239702 --- llvm/lib/Analysis/InstructionSimplify.cpp | 4 ++-- llvm/test/Transforms/InstSimplify/fast-math.ll | 6 +++--- 2 files changed, 5 insertions(+), 5 deletions(-) diff --git a/llvm/lib/Analysis/InstructionSimplify.cpp b/llvm/lib/Analysis/InstructionSimplify.cpp index 5e3b415..8f7a940 100644 --- a/llvm/lib/Analysis/InstructionSimplify.cpp +++ b/llvm/lib/Analysis/InstructionSimplify.cpp @@ -854,8 +854,8 @@ static Value *SimplifyFSubInst(Value *Op0, Value *Op1, FastMathFlags FMF, return X; } - // fsub nnan ninf x, x ==> 0.0 - if (FMF.noNaNs() && FMF.noInfs() && Op0 == Op1) + // fsub nnan x, x ==> 0.0 + if (FMF.noNaNs() && Op0 == Op1) return Constant::getNullValue(Op0->getType()); return nullptr; diff --git a/llvm/test/Transforms/InstSimplify/fast-math.ll b/llvm/test/Transforms/InstSimplify/fast-math.ll index 0336301..c9ae7ef 100644 --- a/llvm/test/Transforms/InstSimplify/fast-math.ll +++ b/llvm/test/Transforms/InstSimplify/fast-math.ll @@ -70,17 +70,17 @@ define float @fadd_fsub_0(float %a) { ret float %ret } -; fsub nnan ninf x, x ==> 0.0 +; fsub nnan x, x ==> 0.0 ; CHECK-LABEL: @fsub_x_x( define float @fsub_x_x(float %a) { ; X - X ==> 0 - %zero1 = fsub nnan ninf float %a, %a + %zero1 = fsub nnan float %a, %a ; Dont fold ; CHECK: %no_zero1 = fsub %no_zero1 = fsub ninf float %a, %a ; CHECK: %no_zero2 = fsub - %no_zero2 = fsub nnan float %a, %a + %no_zero2 = fsub float %a, %a ; CHECK: %no_zero = fadd %no_zero = fadd float %no_zero1, %no_zero2 -- 2.7.4