[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

1 files changed, 8 insertions, 3 deletions

diff --git a/llvm/lib/Transforms/InstCombine/InstCombineAndOrXor.cpp b/llvm/lib/Transforms/InstCombine/InstCombineAndOrXor.cpp
index 8cf48dc5b77..a97b5a9ec0b 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);
   }