[InstCombine] Fold (A | B) ^ (A & C) --> A ? ~C : B

Author: dtcxzyw

llvm/lib/Transforms/InstCombine/InstCombineAndOrXor.cpp

@@ -4972,8 +4972,8 @@ Instruction *InstCombinerImpl::visitXor(BinaryOperator &I) {
 
   // (A & B) ^ (A | C) --> A ? ~B : C -- There are 4 commuted variants.
   if (I.getType()->isIntOrIntVectorTy(1) &&
-      match(Op0, m_OneUse(m_LogicalAnd(m_Value(A), m_Value(B)))) &&
-      match(Op1, m_OneUse(m_LogicalOr(m_Value(C), m_Value(D))))) {
+      match(&I, m_c_Xor(m_OneUse(m_LogicalAnd(m_Value(A), m_Value(B))),
+                        m_OneUse(m_LogicalOr(m_Value(C), m_Value(D)))))) {
     bool NeedFreeze = isa<SelectInst>(Op0) && isa<SelectInst>(Op1) && B == D;
     if (B == C || B == D)
       std::swap(A, B);

llvm/test/Transforms/InstCombine/xor-and-or.ll

@@ -27,9 +27,8 @@ define i1 @xor_logic_and_logic_or2(i1 %c, i1 %x, i1 %y) {
 
 define i1 @xor_logic_and_logic_or2_commuted(i1 %c, i1 %x, i1 %y) {
 ; CHECK-LABEL: @xor_logic_and_logic_or2_commuted(
-; CHECK-NEXT:    [[O:%.*]] = select i1 [[Y:%.*]], i1 true, i1 [[C:%.*]]
-; CHECK-NEXT:    [[A:%.*]] = select i1 [[C]], i1 [[X:%.*]], i1 false
-; CHECK-NEXT:    [[R:%.*]] = xor i1 [[O]], [[A]]
+; CHECK-NEXT:    [[TMP1:%.*]] = xor i1 [[X:%.*]], true
+; CHECK-NEXT:    [[R:%.*]] = select i1 [[C:%.*]], i1 [[TMP1]], i1 [[Y:%.*]]
 ; CHECK-NEXT:    ret i1 [[R]]
 ;
   %o = select i1 %y, i1 true, i1 %c