[llvm] [DAGCombiner] Fold subtraction if above a constant threshold to `umin` (PR #135194)

[Piotr Fusik via llvm-commits]

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@@ -12074,6 +12078,12 @@ SDValue DAGCombiner::visitSELECT(SDNode *N) {
 
     if (SDValue NewSel = SimplifySelect(DL, N0, N1, N2))
       return NewSel;
+
+    // (select (ugt x, C), (add x, ~C), x) -> (umin (add x, ~C), x)
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pfusik wrote:

Added. It stems from corresponding C code.

https://github.com/llvm/llvm-project/pull/135194