From 28b3aa3663a4c3ed0cf23625a04f5bec8ae90653 Mon Sep 17 00:00:00 2001
From: Sanjay Patel <spatel@rotateright.com>
Date: Fri, 13 Oct 2017 20:12:21 +0000
Subject: [PATCH] [InstCombine] recycle adds for better efficiency

Also, clean up unnecessary matcher capture variable initializations.

llvm-svn: 315743
---
 .../InstCombine/InstCombineAddSub.cpp         | 45 +++++++++----------
 1 file changed, 20 insertions(+), 25 deletions(-)

diff --git a/llvm/lib/Transforms/InstCombine/InstCombineAddSub.cpp b/llvm/lib/Transforms/InstCombine/InstCombineAddSub.cpp
index e07fc73f1c56..22538b402b82 100644
--- a/llvm/lib/Transforms/InstCombine/InstCombineAddSub.cpp
+++ b/llvm/lib/Transforms/InstCombine/InstCombineAddSub.cpp
@@ -1248,36 +1248,31 @@ Instruction *InstCombiner::visitAdd(BinaryOperator &I) {
     }
   }
 
+  Value *A, *B;
   // (add (xor A, B) (and A, B)) --> (or A, B)
-  {
-    Value *A = nullptr, *B = nullptr;
-    if (match(RHS, m_Xor(m_Value(A), m_Value(B))) &&
-        match(LHS, m_c_And(m_Specific(A), m_Specific(B))))
-      return BinaryOperator::CreateOr(A, B);
+  if (match(LHS, m_Xor(m_Value(A), m_Value(B))) &&
+      match(RHS, m_c_And(m_Specific(A), m_Specific(B))))
+    return BinaryOperator::CreateOr(A, B);
 
-    if (match(LHS, m_Xor(m_Value(A), m_Value(B))) &&
-        match(RHS, m_c_And(m_Specific(A), m_Specific(B))))
-      return BinaryOperator::CreateOr(A, B);
-  }
+  // (add (and A, B) (xor A, B)) --> (or A, B)
+  if (match(RHS, m_Xor(m_Value(A), m_Value(B))) &&
+      match(LHS, m_c_And(m_Specific(A), m_Specific(B))))
+    return BinaryOperator::CreateOr(A, B);
 
   // (add (or A, B) (and A, B)) --> (add A, B)
-  {
-    Value *A = nullptr, *B = nullptr;
-    if (match(RHS, m_Or(m_Value(A), m_Value(B))) &&
-        match(LHS, m_c_And(m_Specific(A), m_Specific(B)))) {
-      auto *New = BinaryOperator::CreateAdd(A, B);
-      New->setHasNoSignedWrap(I.hasNoSignedWrap());
-      New->setHasNoUnsignedWrap(I.hasNoUnsignedWrap());
-      return New;
-    }
+  if (match(LHS, m_Or(m_Value(A), m_Value(B))) &&
+      match(RHS, m_c_And(m_Specific(A), m_Specific(B)))) {
+    I.setOperand(0, A);
+    I.setOperand(1, B);
+    return &I;
+  }
 
-    if (match(LHS, m_Or(m_Value(A), m_Value(B))) &&
-        match(RHS, m_c_And(m_Specific(A), m_Specific(B)))) {
-      auto *New = BinaryOperator::CreateAdd(A, B);
-      New->setHasNoSignedWrap(I.hasNoSignedWrap());
-      New->setHasNoUnsignedWrap(I.hasNoUnsignedWrap());
-      return New;
-    }
+  // (add (and A, B) (or A, B)) --> (add A, B)
+  if (match(RHS, m_Or(m_Value(A), m_Value(B))) &&
+      match(LHS, m_c_And(m_Specific(A), m_Specific(B)))) {
+    I.setOperand(0, A);
+    I.setOperand(1, B);
+    return &I;
   }
 
   // TODO(jingyue): Consider willNotOverflowSignedAdd and