[llvm] Matched some basic ISD::AVGFLOORU patterns (PR #84903)

[Simon Pilgrim via llvm-commits]

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@@ -859,6 +859,21 @@ define <4 x i32> @urhadd_v4i32(<4 x i32> %x) {
   ret <4 x i32> %r
 }
 
+define <4 x i32> @fixedwidth(<4 x i32> %a0, <4 x i32> %a1)  {
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RKSimon wrote:

Maybe rename @uhadd_fixedwidth_v4i32 ? You will be adding more fixedwidth tests in this file

https://github.com/llvm/llvm-project/pull/84903