From: Suyog Sarda <suyog.sarda@samsung.com>
Date: Fri, 1 Aug 2014 04:41:43 +0000 (+0000)
Subject: This patch implements transform for pattern "(A & B) | ((~A) ^ B) -> (~A ^ B)".
X-Git-Url: http://plrg.eecs.uci.edu/git/?p=oota-llvm.git;a=commitdiff_plain;h=87569413b074f9b2a2a67b279ec1e254179fcfcc

This patch implements transform for pattern "(A & B) | ((~A) ^ B) -> (~A ^ B)".
Patch Credit to Ankit Jain !

Differential Revision: http://reviews.llvm.org/D4655



git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@214476 91177308-0d34-0410-b5e6-96231b3b80d8
---

diff --git a/lib/Transforms/InstCombine/InstCombineAndOrXor.cpp b/lib/Transforms/InstCombine/InstCombineAndOrXor.cpp
index 51564088e67..60e81ebfd0c 100644
--- a/lib/Transforms/InstCombine/InstCombineAndOrXor.cpp
+++ b/lib/Transforms/InstCombine/InstCombineAndOrXor.cpp
@@ -2167,6 +2167,16 @@ Instruction *InstCombiner::visitOr(BinaryOperator &I) {
         return BinaryOperator::CreateOr(Not, Op0);
       }
 
+  // (A & B) | ((~A) ^ B) -> (~A ^ B)
+  if (match(Op0, m_And(m_Value(A), m_Value(B))) &&
+      match(Op1, m_Xor(m_Not(m_Specific(A)), m_Specific(B))))
+    return BinaryOperator::CreateXor(Builder->CreateNot(A), B);
+
+  // ((~A) ^ B) | (A & B) -> (~A ^ B)
+  if (match(Op0, m_Xor(m_Not(m_Value(A)), m_Value(B))) &&
+      match(Op1, m_And(m_Specific(A), m_Specific(B))))
+    return BinaryOperator::CreateXor(Builder->CreateNot(A), B);
+
   if (SwappedForXor)
     std::swap(Op0, Op1);
 
diff --git a/test/Transforms/InstCombine/or.ll b/test/Transforms/InstCombine/or.ll
index 1a493df6153..8e2e6ad9677 100644
--- a/test/Transforms/InstCombine/or.ll
+++ b/test/Transforms/InstCombine/or.ll
@@ -427,3 +427,25 @@ define i32 @test40(i32 %a, i32 %b) {
  %or = or i32 %and, %xor
  ret i32 %or
 }
+
+define i32 @test41(i32 %a, i32 %b) {
+; CHECK-LABEL: test41(
+; CHECK-NEXT: %1 = xor i32 %a, -1
+; CHECK-NEXT: %or = xor i32 %1, %b
+ %and = and i32 %a, %b
+ %nega = xor i32 %a, -1
+ %xor = xor i32 %nega, %b
+ %or = or i32 %and, %xor
+ ret i32 %or
+}
+
+define i32 @test42(i32 %a, i32 %b) {
+; CHECK-LABEL: test42(
+; CHECK-NEXT: %1 = xor i32 %a, -1
+; CHECK-NEXT: %or = xor i32 %1, %b
+ %nega = xor i32 %a, -1
+ %xor = xor i32 %nega, %b
+ %and = and i32 %a, %b
+ %or = or i32 %xor, %and
+ ret i32 %or
+}