[llvm] [AArch64][GlobalISel] Fold buildvector of bitcast (PR #141553)

[David Green via llvm-commits]

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@@ -127,25 +127,9 @@ define void @v4i8(ptr %px, ptr %py, ptr %pz) nounwind {
 ;
 ; CHECK-GI-LABEL: v4i8:
 ; CHECK-GI:       // %bb.0:
-; CHECK-GI-NEXT:    ldr w8, [x0]
-; CHECK-GI-NEXT:    ldr w9, [x1]
-; 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:    sqadd v0.8b, v3.8b, v5.8b
+; CHECK-GI-NEXT:    ldr s0, [x0]
----------------
davemgreen wrote:

This is one of the times where widening is better than promotion.

https://github.com/llvm/llvm-project/pull/141553