[llvm] [DAG] Enhance SDPatternMatch to match integer minimum and maximum patterns in addition to the existing ISD nodes. (PR #111774)

[Simon Pilgrim via llvm-commits]

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@@ -542,6 +542,80 @@ struct BinaryOpc_match {
   }
 };
 
+template <typename LHS_P, typename RHS_P, typename Pred_t,
+          bool Commutable = false, bool ExcludeChain = false>
+struct MaxMin_match {
+  using PredType = Pred_t;
+  LHS_P LHS;
+  RHS_P RHS;
+
+  MaxMin_match(const LHS_P &L, const RHS_P &R) : LHS(L), RHS(R) {}
+
+  template <typename MatchContext>
+  bool match(const MatchContext &Ctx, SDValue N) {
+    if (sd_context_match(N, Ctx, m_Opc(ISD::SELECT))) {
+      EffectiveOperands<ExcludeChain> EO_SELECT(N, Ctx);
+      assert(EO_SELECT.Size == 3);
+      SDValue Cond = N->getOperand(EO_SELECT.FirstIndex);
+      SDValue TrueValue = N->getOperand(EO_SELECT.FirstIndex + 1);
+      SDValue FalseValue = N->getOperand(EO_SELECT.FirstIndex + 2);
+
+      if (sd_context_match(Cond, Ctx, m_Opc(ISD::SETCC))) {
+        EffectiveOperands<ExcludeChain> EO_SETCC(Cond, Ctx);
+        assert(EO_SETCC.Size == 3);
+        SDValue L = Cond->getOperand(EO_SETCC.FirstIndex);
+        SDValue R = Cond->getOperand(EO_SETCC.FirstIndex + 1);
+        CondCodeSDNode *CondNode =
----------------
RKSimon wrote:

(style) `auto *CondNode` = 

https://github.com/llvm/llvm-project/pull/111774