[llvm] [AArch64] Remove copy instruction between uaddlv with v8i16 and dup (PR #66068)

[David Green via llvm-commits]

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@@ -194,8 +194,23 @@ entry:
   ret <8 x i8> %vrshrn_n2
 }
 
-declare <8 x i8> @llvm.aarch64.neon.rshrn.v8i8(<8 x i16>, i32)
+define dso_local <8 x i16> @uaddlv_dup_v8i16(<8 x i16> %a) {
+; CHECK-LABEL: uaddlv_dup_v8i16:
+; CHECK:       // %bb.0: // %entry
+; CHECK-NEXT:    uaddlv s0, v0.8h
+; CHECK-NEXT:    dup v1.8h, v0.h[0]
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davemgreen wrote:

I think the .8h might be incorrect here?

https://github.com/llvm/llvm-project/pull/66068