[llvm] [LV][EVL] Generate negative strided load/store for reversed load/store (PR #123608)

[Florian Hahn via llvm-commits]

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@@ -1776,6 +1776,10 @@ class TargetTransformInfo {
   /// otherwise scalar epilogue loop.
   bool preferEpilogueVectorization() const;
 
+  /// Return true if the loop vectorizer prefer strided load/store when
+  /// vectorizing reversed load/store.
+  bool preferStridedLoadStore() const;
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fhahn wrote:

maybe more generally, why do we need such a helper at all? Could we not query the cost of the strided & reverse versions and just select the best one when the recipe is constructed?

https://github.com/llvm/llvm-project/pull/123608