[llvm] [DAGCombiner] Fold subtraction if above threshold to `umin` (PR #134235)

[Piotr Fusik via llvm-commits]

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@@ -1479,3 +1479,215 @@ entry:
   %cmp = icmp ne i32 %popcnt, 1
   ret i1 %cmp
 }
+
+define i8 @sub_if_uge_i8(i8 %x, i8 %y) {
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pfusik wrote:

Do you mean the function name? `sub_zero_if_ult_y_otherwise_sub_y` is more verbose, but I don't think it's easier to understand.

https://github.com/llvm/llvm-project/pull/134235