[llvm] [LV] Fix missing MetaData for histogram instructions (PR #134241)

[Florian Hahn via llvm-commits]

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@@ -2143,20 +2143,21 @@ class LLVM_ABI_FOR_TEST VPWidenCallRecipe : public VPRecipeWithIRFlags,
 /// lanes, which is handled by the llvm.experimental.vector.histogram family
 /// of intrinsics. The only update operations currently supported are
 /// 'add' and 'sub' where the other term is loop-invariant.
-class VPHistogramRecipe : public VPRecipeBase {
+class VPHistogramRecipe : public VPRecipeBase, public VPIRMetadata {
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fhahn wrote:

I think you'll also need to update `::print` to print the metadata. Would also be good to add test coverage for printing to `llvm/test/Transforms/LoopVectorize/VPlan/AArch64/sve2-histcnt-vplan.ll`

https://github.com/llvm/llvm-project/pull/134241