[llvm] [LV] Support strided load with a stride of -1 (PR #128718)

[Alexey Bataev via llvm-commits]

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@@ -1718,6 +1737,9 @@ class LoopVectorizationCostModel {
         Ops, [this, VF](Value *V) { return this->needsExtract(V, VF); }));
   }
 
+  /// The mapping of memory access instructions to their stride values.
+  DenseMap<Instruction *, int64_t> StrideInfo;
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alexey-bataev wrote:

1. SmallDenseMap
2. Better to map to a value (or SCEV) to support runtime strides, no?

https://github.com/llvm/llvm-project/pull/128718