[llvm] [LV] Adjust exit recipe detection to run on early vplan (PR #183318)

[David Sherwood via llvm-commits]

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@@ -407,16 +414,23 @@ class LoopVectorizationLegality {
     return LAI->getDepChecker().getMaxSafeVectorWidthInBits();
   }
 
+  UncountableEarlyExitDetail getUncountableEarlyExitDetail() const {
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david-arm wrote:

nit: Can you leave a brief '///' comment same as other functions?

https://github.com/llvm/llvm-project/pull/183318