1 files changed, 8 insertions, 0 deletions
diff --git a/llvm/lib/Analysis/InstructionSimplify.cpp b/llvm/lib/Analysis/InstructionSimplify.cpp
index 22ced5a8665..13805437b54 100644
--- a/llvm/lib/Analysis/InstructionSimplify.cpp
+++ b/llvm/lib/Analysis/InstructionSimplify.cpp
@@ -4359,6 +4359,14 @@ static Value *SimplifyFAddInst(Value *Op0, Value *Op1, FastMathFlags FMF,
                        match(Op1, m_FSub(m_AnyZeroFP(), m_Specific(Op0)))))
     return ConstantFP::getNullValue(Op0->getType());
 
+  // (X - Y) + Y --> X
+  // Y + (X - Y) --> X
+  Value *X;
+  if (FMF.noSignedZeros() && FMF.allowReassoc() &&
+      (match(Op0, m_FSub(m_Value(X), m_Specific(Op1))) ||
+       match(Op1, m_FSub(m_Value(X), m_Specific(Op0)))))
+    return X;
+
   return nullptr;
 }