[llvm] [GlobalISel] Combine G_UNMERGE_VALUES with anyext and build vector (PR #112370)

[Thorsten Schütt via llvm-commits]

================
@@ -498,21 +500,23 @@ define void @or_v4i8(ptr %p1, ptr %p2) {
 ; CHECK-GI-NEXT:    fmov s0, w8
 ; CHECK-GI-NEXT:    fmov s1, w9
 ; CHECK-GI-NEXT:    mov b2, v0.b[1]
-; CHECK-GI-NEXT:    mov v3.b[0], v0.b[0]
-; CHECK-GI-NEXT:    mov b4, v1.b[1]
-; CHECK-GI-NEXT:    mov v5.b[0], v1.b[0]
-; CHECK-GI-NEXT:    mov v3.b[1], v2.b[0]
-; CHECK-GI-NEXT:    mov b2, v0.b[2]
-; CHECK-GI-NEXT:    mov b0, v0.b[3]
-; CHECK-GI-NEXT:    mov v5.b[1], v4.b[0]
-; CHECK-GI-NEXT:    mov b4, v1.b[2]
-; CHECK-GI-NEXT:    mov b1, v1.b[3]
-; CHECK-GI-NEXT:    mov v3.b[2], v2.b[0]
-; CHECK-GI-NEXT:    mov v5.b[2], v4.b[0]
-; CHECK-GI-NEXT:    mov v3.b[3], v0.b[0]
-; CHECK-GI-NEXT:    mov v5.b[3], v1.b[0]
-; CHECK-GI-NEXT:    ushll v0.8h, v3.8b, #0
-; CHECK-GI-NEXT:    ushll v1.8h, v5.8b, #0
+; CHECK-GI-NEXT:    mov b3, v1.b[1]
+; CHECK-GI-NEXT:    mov b4, v0.b[2]
+; CHECK-GI-NEXT:    mov b5, v0.b[3]
+; CHECK-GI-NEXT:    fmov w8, s2
+; CHECK-GI-NEXT:    mov b2, v1.b[2]
+; CHECK-GI-NEXT:    fmov w9, s3
+; CHECK-GI-NEXT:    mov b3, v1.b[3]
+; CHECK-GI-NEXT:    mov v0.h[1], w8
+; CHECK-GI-NEXT:    mov v1.h[1], w9
+; CHECK-GI-NEXT:    fmov w8, s4
+; CHECK-GI-NEXT:    fmov w9, s2
+; CHECK-GI-NEXT:    mov v0.h[2], w8
+; CHECK-GI-NEXT:    mov v1.h[2], w9
+; CHECK-GI-NEXT:    fmov w8, s5
+; CHECK-GI-NEXT:    fmov w9, s3
+; CHECK-GI-NEXT:    mov v0.h[3], w8
+; CHECK-GI-NEXT:    mov v1.h[3], w9
----------------
tschuett wrote:

The code after the legalizer contains the unmerge(anyext(buildvector)) pattern.

There is also unmerge(trunc(buildvector)). Maybe future work.

Note that we are before the post legalizer combiner.

https://github.com/llvm/llvm-project/pull/112370