From: Benjamin Kramer <benny.kra@googlemail.com>
Date: Mon, 29 Feb 2016 12:18:25 +0000 (+0000)
Subject: [InstSimplify] Restore fsub 0.0, (fsub 0.0, X) ==> X optzn
X-Git-Tag: llvmorg-3.9.0-rc1~12933
X-Git-Url: http://review.tizen.org/git/?a=commitdiff_plain;h=6bb15021b37cd79e0fa8c361880756f90d9b5ba3;p=platform%2Fupstream%2Fllvm.git

[InstSimplify] Restore fsub 0.0, (fsub 0.0, X) ==> X optzn

I accidentally removed this in r262212 but there was no test coverage to
detect it.

llvm-svn: 262215
---

diff --git a/llvm/lib/Analysis/InstructionSimplify.cpp b/llvm/lib/Analysis/InstructionSimplify.cpp
index aca19de..bb0a275 100644
--- a/llvm/lib/Analysis/InstructionSimplify.cpp
+++ b/llvm/lib/Analysis/InstructionSimplify.cpp
@@ -839,7 +839,7 @@ static Value *SimplifyFSubInst(Value *Op0, Value *Op1, FastMathFlags FMF,
     return X;
 
   // fsub 0.0, (fsub 0.0, X) ==> X if signed zeros are ignored.
-  if (FMF.noSignedZeros() && match(Op0, m_NegZero()) &&
+  if (FMF.noSignedZeros() && match(Op0, m_AnyZero()) &&
       match(Op1, m_FSub(m_AnyZero(), m_Value(X))))
     return X;
 
diff --git a/llvm/test/Transforms/InstSimplify/fast-math.ll b/llvm/test/Transforms/InstSimplify/fast-math.ll
index 90532fa..c499af3 100644
--- a/llvm/test/Transforms/InstSimplify/fast-math.ll
+++ b/llvm/test/Transforms/InstSimplify/fast-math.ll
@@ -91,6 +91,16 @@ define float @fsub_x_x(float %a) {
   ret float %ret
 }
 
+; fsub nsz 0.0, (fsub 0.0, X) ==> X
+; CHECK-LABEL: @fsub_0_0_x(
+define float @fsub_0_0_x(float %a) {
+  %t1 = fsub float 0.0, %a
+  %ret = fsub nsz float 0.0, %t1
+
+; CHECK: ret float %a
+  ret float %ret
+}
+
 ; fadd nsz X, 0 ==> X
 ; CHECK-LABEL: @nofold_fadd_x_0(
 define float @nofold_fadd_x_0(float %a) {