From: Craig Topper <craig.topper@gmail.com>
Date: Tue, 25 Apr 2017 15:19:04 +0000 (+0000)
Subject: [InstCombine] Add missing commute handling to (A | B) & (B ^ (~A)) -> (A & B)
X-Git-Tag: llvmorg-5.0.0-rc1~6736
X-Git-Url: http://review.tizen.org/git/?a=commitdiff_plain;h=ba011431938ec4e1716c13a1aada4510f547c89f;p=platform%2Fupstream%2Fllvm.git

[InstCombine] Add missing commute handling to (A | B) & (B ^ (~A)) -> (A & B)

The matching here wasn't able to handle all the possible commutes. It always assumed the not would be on the left of the xor, but that's not guaranteed.

Differential Revision: https://reviews.llvm.org/D32474

llvm-svn: 301316
---

diff --git a/llvm/lib/Transforms/InstCombine/InstCombineAndOrXor.cpp b/llvm/lib/Transforms/InstCombine/InstCombineAndOrXor.cpp
index 8cf48dc..a97b5a9 100644
--- a/llvm/lib/Transforms/InstCombine/InstCombineAndOrXor.cpp
+++ b/llvm/lib/Transforms/InstCombine/InstCombineAndOrXor.cpp
@@ -1425,13 +1425,18 @@ Instruction *InstCombiner::visitAnd(BinaryOperator &I) {
           return BinaryOperator::CreateAnd(Op1, Builder->CreateNot(C));
 
     // (A | B) & ((~A) ^ B) -> (A & B)
-    if (match(Op0, m_Or(m_Value(A), m_Value(B))) &&
-        match(Op1, m_Xor(m_Not(m_Specific(A)), m_Specific(B))))
+    // (A | B) & (B ^ (~A)) -> (A & B)
+    // (B | A) & ((~A) ^ B) -> (A & B)
+    // (B | A) & (B ^ (~A)) -> (A & B)
+    if (match(Op1, m_c_Xor(m_Not(m_Value(A)), m_Value(B))) &&
+        match(Op0, m_c_Or(m_Specific(A), m_Specific(B))))
       return BinaryOperator::CreateAnd(A, B);
 
     // ((~A) ^ B) & (A | B) -> (A & B)
     // ((~A) ^ B) & (B | A) -> (A & B)
-    if (match(Op0, m_Xor(m_Not(m_Value(A)), m_Value(B))) &&
+    // (B ^ (~A)) & (A | B) -> (A & B)
+    // (B ^ (~A)) & (B | A) -> (A & B)
+    if (match(Op0, m_c_Xor(m_Not(m_Value(A)), m_Value(B))) &&
         match(Op1, m_c_Or(m_Specific(A), m_Specific(B))))
       return BinaryOperator::CreateAnd(A, B);
   }
diff --git a/llvm/test/Transforms/InstCombine/and.ll b/llvm/test/Transforms/InstCombine/and.ll
index 1816b24..a2715c1 100644
--- a/llvm/test/Transforms/InstCombine/and.ll
+++ b/llvm/test/Transforms/InstCombine/and.ll
@@ -617,10 +617,7 @@ final:
 define i32 @test42(i32 %a, i32 %c, i32 %d) {
 ; CHECK-LABEL: @test42(
 ; CHECK-NEXT:    [[FORCE:%.*]] = mul i32 [[C:%.*]], [[D:%.*]]
-; CHECK-NEXT:    [[OR:%.*]] = or i32 [[FORCE]], [[A:%.*]]
-; CHECK-NEXT:    [[NOTA:%.*]] = xor i32 [[A]], -1
-; CHECK-NEXT:    [[XOR:%.*]] = xor i32 [[FORCE]], [[NOTA]]
-; CHECK-NEXT:    [[AND:%.*]] = and i32 [[XOR]], [[OR]]
+; CHECK-NEXT:    [[AND:%.*]] = and i32 [[FORCE]], [[A:%.*]]
 ; CHECK-NEXT:    ret i32 [[AND]]
 ;
   %force = mul i32 %c, %d ; forces the complexity sorting
@@ -634,10 +631,7 @@ define i32 @test42(i32 %a, i32 %c, i32 %d) {
 define i32 @test43(i32 %a, i32 %c, i32 %d) {
 ; CHECK-LABEL: @test43(
 ; CHECK-NEXT:    [[FORCE:%.*]] = mul i32 [[C:%.*]], [[D:%.*]]
-; CHECK-NEXT:    [[OR:%.*]] = or i32 [[FORCE]], [[A:%.*]]
-; CHECK-NEXT:    [[NOTA:%.*]] = xor i32 [[A]], -1
-; CHECK-NEXT:    [[XOR:%.*]] = xor i32 [[FORCE]], [[NOTA]]
-; CHECK-NEXT:    [[AND:%.*]] = and i32 [[OR]], [[XOR]]
+; CHECK-NEXT:    [[AND:%.*]] = and i32 [[FORCE]], [[A:%.*]]
 ; CHECK-NEXT:    ret i32 [[AND]]
 ;
   %force = mul i32 %c, %d ; forces the complexity sorting