[llvm] [AArch64] Improve index selection for histograms (PR #111150)

[Benjamin Maxwell via llvm-commits]

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@@ -267,5 +267,79 @@ define void @histogram_i16_8_lane(ptr %base, <vscale x 8 x i32> %indices, i16 %i
   ret void
 }
 
+define void @histogram_i32_zextend(ptr %base, <vscale x 4 x i32> %indices, <vscale x 4 x i1> %mask) #0 {
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MacDue wrote:

It might be worth testing a few more index types maybe `i8` and `i16` to check those cases are working too :thinking: 

https://github.com/llvm/llvm-project/pull/111150