[InstCombine] Implement ((B ^ C) & A) | B -> B | (A & C)

We already have this for the OR variant, but this works for XOR as well.

Author: AZero13

llvm/lib/Transforms/InstCombine/InstCombineAndOrXor.cpp

@@ -3544,6 +3544,14 @@ Instruction *InstCombinerImpl::visitOr(BinaryOperator &I) {
   if (match(Op1, m_c_And(m_c_Or(m_Specific(Op0), m_Value(C)), m_Value(A))))
     return BinaryOperator::CreateOr(Op0, Builder.CreateAnd(A, C));
 
+  // ((B ^ C) & A) | B -> B | (A & C)
+  if (match(Op0, m_c_And(m_c_Xor(m_Specific(Op1), m_Value(C)), m_Value(A))))
+    return BinaryOperator::CreateOr(Op1, Builder.CreateAnd(A, C));
+
+  // B | ((B ^ C) & A) -> B | (A & C)
+  if (match(Op1, m_c_And(m_c_Xor(m_Specific(Op0), m_Value(C)), m_Value(A))))
+    return BinaryOperator::CreateOr(Op0, Builder.CreateAnd(A, C));
+
   if (Instruction *DeMorgan = matchDeMorgansLaws(I, *this))
     return DeMorgan;
 

llvm/test/Transforms/InstCombine/or.ll

@@ -801,9 +801,8 @@ define i32 @test45_commuted3(i32 %x, i32 %y, i32 %z) {
 
 define i32 @test45a(i32 %x, i32 %y, i32 %z) {
 ; CHECK-LABEL: @test45a(
-; CHECK-NEXT:    [[XOR:%.*]] = xor i32 [[Y:%.*]], [[Z:%.*]]
-; CHECK-NEXT:    [[AND:%.*]] = and i32 [[XOR]], [[X:%.*]]
-; CHECK-NEXT:    [[OR:%.*]] = or i32 [[AND]], [[Y]]
+; CHECK-NEXT:    [[TMP1:%.*]] = and i32 [[X:%.*]], [[Z:%.*]]
+; CHECK-NEXT:    [[OR:%.*]] = or i32 [[TMP1]], [[Y:%.*]]
 ; CHECK-NEXT:    ret i32 [[OR]]
 ;
   %xor = xor i32 %y, %z
@@ -815,9 +814,8 @@ define i32 @test45a(i32 %x, i32 %y, i32 %z) {
 define i32 @test45a_commuted1(i32 %x, i32 %y, i32 %z) {
 ; CHECK-LABEL: @test45a_commuted1(
 ; CHECK-NEXT:    [[YY:%.*]] = mul i32 [[Y:%.*]], [[Y]]
-; CHECK-NEXT:    [[XOR:%.*]] = xor i32 [[YY]], [[Z:%.*]]
-; CHECK-NEXT:    [[AND:%.*]] = and i32 [[XOR]], [[X:%.*]]
-; CHECK-NEXT:    [[OR:%.*]] = or i32 [[YY]], [[AND]]
+; CHECK-NEXT:    [[TMP1:%.*]] = and i32 [[X:%.*]], [[Z:%.*]]
+; CHECK-NEXT:    [[OR:%.*]] = or i32 [[YY]], [[TMP1]]
 ; CHECK-NEXT:    ret i32 [[OR]]
 ;
   %yy = mul i32 %y, %y ; thwart complexity-based ordering
@@ -831,9 +829,8 @@ define i32 @test45a_commuted2(i32 %x, i32 %y, i32 %z) {
 ; CHECK-LABEL: @test45a_commuted2(
 ; CHECK-NEXT:    [[YY:%.*]] = mul i32 [[Y:%.*]], [[Y]]
 ; CHECK-NEXT:    [[XX:%.*]] = mul i32 [[X:%.*]], [[X]]
-; CHECK-NEXT:    [[XOR:%.*]] = xor i32 [[YY]], [[Z:%.*]]
-; CHECK-NEXT:    [[AND:%.*]] = and i32 [[XX]], [[XOR]]
-; CHECK-NEXT:    [[OR:%.*]] = or i32 [[AND]], [[YY]]
+; CHECK-NEXT:    [[TMP1:%.*]] = and i32 [[XX]], [[Z:%.*]]
+; CHECK-NEXT:    [[OR:%.*]] = or i32 [[YY]], [[TMP1]]
 ; CHECK-NEXT:    ret i32 [[OR]]
 ;
   %yy = mul i32 %y, %y ; thwart complexity-based ordering
@@ -848,9 +845,8 @@ define i32 @test45a_commuted3(i32 %x, i32 %y, i32 %z) {
 ; CHECK-LABEL: @test45a_commuted3(
 ; CHECK-NEXT:    [[YY:%.*]] = mul i32 [[Y:%.*]], [[Y]]
 ; CHECK-NEXT:    [[ZZ:%.*]] = mul i32 [[Z:%.*]], [[Z]]
-; CHECK-NEXT:    [[XOR:%.*]] = xor i32 [[ZZ]], [[YY]]
-; CHECK-NEXT:    [[AND:%.*]] = and i32 [[XOR]], [[X:%.*]]
-; CHECK-NEXT:    [[OR:%.*]] = or i32 [[AND]], [[YY]]
+; CHECK-NEXT:    [[TMP1:%.*]] = and i32 [[ZZ]], [[X:%.*]]
+; CHECK-NEXT:    [[OR:%.*]] = or i32 [[YY]], [[TMP1]]
 ; CHECK-NEXT:    ret i32 [[OR]]
 ;
   %yy = mul i32 %y, %y ; thwart complexity-based ordering