[llvm] [LV] Extend FindFirstIV to unsigned case (PR #146386)

[Florian Hahn via llvm-commits]

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@@ -941,6 +941,205 @@ exit:                                             ; preds = %loop
   ret i16 %spec.select.lcssa
 }
 
+; The signed sentinel value for decreasing-IV vectorization is LONG_MAX, and since
+; the IV hits this value with smin vectorization, it needs to be vectorized with a
+; an unsigned sentinel and umin instead.
+define i64 @select_decreasing_induction_icmp_iv_unsigned(ptr %a) {
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fhahn wrote:

Just double-checking, do we have a negative test case where we hit unsigned max?

https://github.com/llvm/llvm-project/pull/146386