diff --git a/llvm/lib/CodeGen/SelectionDAG/SelectionDAG.cpp b/llvm/lib/CodeGen/SelectionDAG/SelectionDAG.cpp
--- a/llvm/lib/CodeGen/SelectionDAG/SelectionDAG.cpp
+++ b/llvm/lib/CodeGen/SelectionDAG/SelectionDAG.cpp
@@ -4686,18 +4686,21 @@
 
 static bool haveNoCommonBitsSetCommutative(SDValue A, SDValue B) {
   // Match masked merge pattern (X & ~M) op (Y & M)
-  if (A->getOpcode() == ISD::AND && B->getOpcode() == ISD::AND) {
-    auto MatchNoCommonBitsPattern = [&](SDValue NotM, SDValue And) {
-      if (isBitwiseNot(NotM, true)) {
-        SDValue NotOperand = NotM->getOperand(0);
-        return NotOperand == And->getOperand(0) ||
-               NotOperand == And->getOperand(1);
-      }
-      return false;
-    };
+  // Including degenerate case (X & ~M) op M
+  auto MatchNoCommonBitsPattern = [&](SDValue NotM, SDValue Other) {
+    if (isBitwiseNot(NotM, true)) {
+      SDValue NotOperand = NotM->getOperand(0);
+      if (Other == NotOperand)
+        return true;
+      if (Other->getOpcode() == ISD::AND)
+        return NotOperand == Other->getOperand(0) ||
+               NotOperand == Other->getOperand(1);
+    }
+    return false;
+  };
+  if (A->getOpcode() == ISD::AND)
     return MatchNoCommonBitsPattern(A->getOperand(0), B) ||
            MatchNoCommonBitsPattern(A->getOperand(1), B);
-  }
   return false;
 }
 
diff --git a/llvm/test/CodeGen/X86/add-and-not.ll b/llvm/test/CodeGen/X86/add-and-not.ll
--- a/llvm/test/CodeGen/X86/add-and-not.ll
+++ b/llvm/test/CodeGen/X86/add-and-not.ll
@@ -7,9 +7,8 @@
 ; CHECK-LABEL: add_and_xor:
 ; CHECK:       # %bb.0:
 ; CHECK-NEXT:    movl %edi, %eax
-; CHECK-NEXT:    notb %al
-; CHECK-NEXT:    andb %sil, %al
-; CHECK-NEXT:    addb %dil, %al
+; CHECK-NEXT:    orl %esi, %eax
+; CHECK-NEXT:    # kill: def $al killed $al killed $eax
 ; CHECK-NEXT:    retq
   %xor = xor i8 %x, -1
   %and = and i8 %xor, %y
@@ -51,9 +50,8 @@
 ; CHECK-LABEL: add_and_xor_commuted1:
 ; CHECK:       # %bb.0:
 ; CHECK-NEXT:    movl %edi, %eax
-; CHECK-NEXT:    notb %al
-; CHECK-NEXT:    andb %sil, %al
-; CHECK-NEXT:    addb %dil, %al
+; CHECK-NEXT:    orl %esi, %eax
+; CHECK-NEXT:    # kill: def $al killed $al killed $eax
 ; CHECK-NEXT:    retq
   %xor = xor i8 %x, -1
   %and = and i8 %y, %xor
@@ -65,9 +63,8 @@
 ; CHECK-LABEL: add_and_xor_commuted2:
 ; CHECK:       # %bb.0:
 ; CHECK-NEXT:    movl %edi, %eax
-; CHECK-NEXT:    notb %al
-; CHECK-NEXT:    andb %sil, %al
-; CHECK-NEXT:    addb %dil, %al
+; CHECK-NEXT:    orl %esi, %eax
+; CHECK-NEXT:    # kill: def $al killed $al killed $eax
 ; CHECK-NEXT:    retq
   %xor = xor i8 %x, -1
   %and = and i8 %xor, %y
@@ -79,9 +76,8 @@
 ; CHECK-LABEL: add_and_xor_commuted3:
 ; CHECK:       # %bb.0:
 ; CHECK-NEXT:    movl %edi, %eax
-; CHECK-NEXT:    notb %al
-; CHECK-NEXT:    andb %sil, %al
-; CHECK-NEXT:    addb %dil, %al
+; CHECK-NEXT:    orl %esi, %eax
+; CHECK-NEXT:    # kill: def $al killed $al killed $eax
 ; CHECK-NEXT:    retq
   %xor = xor i8 %x, -1
   %and = and i8 %y, %xor
@@ -95,18 +91,17 @@
 ; CHECK-NEXT:    pushq %rbp
 ; CHECK-NEXT:    pushq %r14
 ; CHECK-NEXT:    pushq %rbx
-; CHECK-NEXT:    movl %esi, %r14d
-; CHECK-NEXT:    movl %edi, %ebp
-; CHECK-NEXT:    movl %ebp, %eax
+; CHECK-NEXT:    movl %esi, %ebx
+; CHECK-NEXT:    movl %edi, %r14d
+; CHECK-NEXT:    movl %r14d, %eax
 ; CHECK-NEXT:    notb %al
-; CHECK-NEXT:    movzbl %al, %ebx
-; CHECK-NEXT:    movl %ebx, %edi
+; CHECK-NEXT:    movzbl %al, %ebp
+; CHECK-NEXT:    movl %ebp, %edi
 ; CHECK-NEXT:    callq use@PLT
-; CHECK-NEXT:    andb %r14b, %bl
-; CHECK-NEXT:    movzbl %bl, %ebx
-; CHECK-NEXT:    movl %ebx, %edi
+; CHECK-NEXT:    andb %bl, %bpl
+; CHECK-NEXT:    movzbl %bpl, %edi
 ; CHECK-NEXT:    callq use@PLT
-; CHECK-NEXT:    addb %bpl, %bl
+; CHECK-NEXT:    orb %r14b, %bl
 ; CHECK-NEXT:    movl %ebx, %eax
 ; CHECK-NEXT:    popq %rbx
 ; CHECK-NEXT:    popq %r14