[llvm-branch-commits] [llvm] [AArch64][ISel] Select constructive SVE2 ext instruction (PR #151730)

[Sander de Smalen via llvm-branch-commits]

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@@ -4069,6 +4069,22 @@ let Predicates = [HasSVE2_or_SME] in {
   let AddedComplexity = 2 in {
     def : Pat<(nxv16i8 (AArch64ext nxv16i8:$zn1, nxv16i8:$zn2, (i32 imm0_255:$imm))),
               (EXT_ZZI_B (REG_SEQUENCE ZPR2, $zn1, zsub0, $zn2, zsub1), imm0_255:$imm)>;
+
+    foreach VT = [nxv16i8] in
+      def : Pat<(VT (vector_splice VT:$Z1, VT:$Z2, (i64 (sve_ext_imm_0_255 i32:$index)))),
+                (EXT_ZZI_B  (REG_SEQUENCE ZPR2, $Z1, zsub0, $Z2, zsub1), imm0_255:$index)>;
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sdesmalen-arm wrote:

Before I send you off on a wild goose chase, it seems I made this mistake in thinking before as in there _is_ a subtle difference between the two: https://github.com/llvm/llvm-project/pull/114411#discussion_r1824649219

https://github.com/llvm/llvm-project/pull/151730