[llvm] [LV]Split store-load forward distance analysis from other checks, NFC (PR #121156)

[Florian Hahn via llvm-commits]

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@@ -304,6 +310,10 @@ class MemoryDepChecker {
   /// restrictive.
   uint64_t MaxSafeVectorWidthInBits = -1U;
 
+  /// Maximum power-of-2 number of elements, which do not prevent store-load
+  /// forwarding and safe to operate simultaneously.
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fhahn wrote:

```suggestion
  /// Maximum power-of-2 number of elements, which do not prevent store-load
  /// forwarding.
```

Now just for store-load forwarding prevention?

https://github.com/llvm/llvm-project/pull/121156