[llvm] Add target hook for automatic histogram vectorization (PR #128414)

[via llvm-commits]

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@@ -310,6 +310,22 @@ class TargetTransformInfoImplBase {
     return false;
   }
 
+  bool isLegalForHistogramVectorization(const LoadInst *LI,
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RonDahan101 wrote:

When investigating your approach, I realized that IntrinsicCostAttributes already contains the GEP pointer, which includes the address space information. By adjusting the cost (or simply marking it as invalid), I can control which histogram operations I'd like to support.
Thank you for the feedback!
I'll go ahead and close the PR.

https://github.com/llvm/llvm-project/pull/128414