[llvm] [LV] Also clamp MaxVF by trip count when maximizing vector bandwidth. (PR #149794)

[David Sherwood via llvm-commits]

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@@ -3940,6 +3951,8 @@ ElementCount LoopVectorizationCostModel::getMaximizedVFForTarget(
       }
     }
 
+    MaxVF = clampVFByMaxTripCount(MaxVF, MaxTripCount, FoldTailByMasking);
+
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david-arm wrote:

Should we be invalidating cost modelling decisions if we clamp back to MaxVectorElementCount, since nothing will have changed?

https://github.com/llvm/llvm-project/pull/149794