[llvm] [LoopVectorize] Fix divide-by-zero bug (#80836) (PR #81721)

[Paul Walker via llvm-commits]

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@@ -2106,16 +2106,18 @@ class GeneratedRTChecks {
               BestTripCount = *EstimatedTC;
           }
 
+          BestTripCount = std::max(BestTripCount, (unsigned)1);
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paulwalker-arm wrote:

Not a strongly held view but can `(unsigned)1` become `1U`?

https://github.com/llvm/llvm-project/pull/81721