[llvm] [X86] Match SETCC_CARRY in addition of SUB when trying to reconstruct LEA (PR #126551)

[Phoebe Wang via llvm-commits]

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@@ -51985,21 +51985,30 @@ static SDValue combineOr(SDNode *N, SelectionDAG &DAG,
     return R;
 
   // (0 - SetCC) | C -> (zext (not SetCC)) * (C + 1) - 1 if we can get a LEA out of it.
-  if ((VT == MVT::i32 || VT == MVT::i64) &&
-      N0.getOpcode() == ISD::SUB && N0.hasOneUse() &&
-      isNullConstant(N0.getOperand(0))) {
-    SDValue Cond = N0.getOperand(1);
-    if (Cond.getOpcode() == ISD::ZERO_EXTEND && Cond.hasOneUse())
-      Cond = Cond.getOperand(0);
-
-    if (Cond.getOpcode() == X86ISD::SETCC && Cond.hasOneUse()) {
-      if (auto *CN = dyn_cast<ConstantSDNode>(N1)) {
-        uint64_t Val = CN->getZExtValue();
-        if (Val == 1 || Val == 2 || Val == 3 || Val == 4 || Val == 7 || Val == 8) {
-          X86::CondCode CCode = (X86::CondCode)Cond.getConstantOperandVal(0);
-          CCode = X86::GetOppositeBranchCondition(CCode);
-          SDValue NotCond = getSETCC(CCode, Cond.getOperand(1), SDLoc(Cond), DAG);
+  if (VT == MVT::i32 || VT == MVT::i64) {
+    if (auto *CN = dyn_cast<ConstantSDNode>(N1)) {
+      unsigned Val = CN->getZExtValue();
+      if (Val == 1 || Val == 2 || Val == 3 || Val == 4 || Val == 7 ||
+          Val == 8) {
+        SDValue NotCond;
+        if (N0.getOpcode() == X86ISD::SETCC_CARRY && N0.hasOneUse() &&
+            N0.getOperand(1).hasOneUse()) {
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phoebewang wrote:

`N0.hasOneUse() && N0.getOperand(1).hasOneUse()` can be hoisted out?

https://github.com/llvm/llvm-project/pull/126551