[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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@@ -609,23 +683,27 @@ inline BinaryOpc_match<LHS, RHS, true> m_Xor(const LHS &L, const RHS &R) {
 }
 
 template <typename LHS, typename RHS>
-inline BinaryOpc_match<LHS, RHS, true> m_SMin(const LHS &L, const RHS &R) {
-  return BinaryOpc_match<LHS, RHS, true>(ISD::SMIN, L, R);
+inline auto m_SMin(const LHS &L, const RHS &R) {
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RKSimon wrote:

Based off the discussion with @nikic on #108218 - we need to name these variants m_SMinLike (etc.) - these will match BOTH the ISD node and the MaxMin pattern. We then keep m_SMin (etc.) to just match the ISD node. 

You will then need to update the ABD matchers in DAGCombiner.visitSUB to use the Like variants.

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