[llvm] Match fixed width ISD::AVGFLOORS + ISD::AVGCEILS patterns (PR #86222)

[Simon Pilgrim via llvm-commits]

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@@ -341,6 +341,18 @@ define <8 x i16> @sub_fixedwidth_v4i32(<8 x i16> %a0, <8 x i16> %a1)  {
   ret <8 x i16> %res
 }
 
+define <8 x i16> @shsub_fixedwidth_v4i32(<8 x i16> %a0, <8 x i16> %a1)  {
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RKSimon wrote:

shsub_fixedwidth_v4i32 -> srhadd_fixedwidth_v8i16 (its matching the shsub instruction for v8i16 types)

https://github.com/llvm/llvm-project/pull/86222