[llvm] [RISCV] Add lowerVECTOR_SHUFFLEAsCONCAT_VECTORS. (PR #109948)

[Luke Lau via llvm-commits]

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@@ -0,0 +1,36 @@
+; NOTE: Assertions have been autogenerated by utils/update_llc_test_checks.py
+; RUN: llc -mtriple riscv64 -mattr=+v -riscv-v-vector-bits-min=512 -verify-machineinstrs < %s | FileCheck %s
+
+define <16 x float> @test1(<8 x float> %0) {
+; CHECK-LABEL: test1:
+; CHECK:       # %bb.0: # %entry
+; CHECK-NEXT:    vmv1r.v v9, v8
+; CHECK-NEXT:    vsetivli zero, 16, e32, m1, ta, ma
+; CHECK-NEXT:    vslideup.vi v9, v8, 8
+; CHECK-NEXT:    vmv.v.v v8, v9
+; CHECK-NEXT:    ret
+entry:
+  %1 = call <16 x float> @llvm.vector.insert.v16f32.v8f32(<16 x float> poison, <8 x float> poison, i64 8)
+  %2 = call <16 x float> @llvm.vector.insert.v16f32.v8f32(<16 x float> %1, <8 x float> %0, i64 0)
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lukel97 wrote:

Does inserting a poison subvector into a posion vector do anything?

https://github.com/llvm/llvm-project/pull/109948