[llvm] [GlobalISel] Refactor extractParts() (PR #75223)

[Amara Emerson via llvm-commits]

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@@ -460,12 +460,14 @@ body:             |
     ; CHECK-NEXT: [[EVEC3:%[0-9]+]]:_(s32) = G_EXTRACT_VECTOR_ELT [[SHUF]](<4 x s32>), [[C3]](s64)
     ; CHECK-NEXT: [[EVEC4:%[0-9]+]]:_(s32) = G_EXTRACT_VECTOR_ELT [[SHUF1]](<4 x s32>), [[C]](s64)
     ; CHECK-NEXT: [[EVEC5:%[0-9]+]]:_(s32) = G_EXTRACT_VECTOR_ELT [[SHUF1]](<4 x s32>), [[C1]](s64)
-    ; CHECK-NEXT: [[BUILD_VECTOR2:%[0-9]+]]:_(<4 x s32>) = G_BUILD_VECTOR [[EVEC]](s32), [[EVEC1]](s32), [[EVEC2]](s32), [[EVEC3]](s32)
-    ; CHECK-NEXT: [[BUILD_VECTOR3:%[0-9]+]]:_(<2 x s32>) = G_BUILD_VECTOR [[EVEC4]](s32), [[EVEC5]](s32)
-    ; CHECK-NEXT: G_STORE [[BUILD_VECTOR2]](<4 x s32>), [[COPY8]](p0) :: (store (<4 x s32>), align 32)
+    ; CHECK-NEXT: [[BUILD_VECTOR2:%[0-9]+]]:_(<2 x s32>) = G_BUILD_VECTOR [[EVEC]](s32), [[EVEC1]](s32)
+    ; CHECK-NEXT: [[BUILD_VECTOR3:%[0-9]+]]:_(<2 x s32>) = G_BUILD_VECTOR [[EVEC2]](s32), [[EVEC3]](s32)
+    ; CHECK-NEXT: [[BUILD_VECTOR4:%[0-9]+]]:_(<2 x s32>) = G_BUILD_VECTOR [[EVEC4]](s32), [[EVEC5]](s32)
+    ; CHECK-NEXT: [[CONCAT_VECTORS:%[0-9]+]]:_(<4 x s32>) = G_CONCAT_VECTORS [[BUILD_VECTOR2]](<2 x s32>), [[BUILD_VECTOR3]](<2 x s32>)
+    ; CHECK-NEXT: G_STORE [[CONCAT_VECTORS]](<4 x s32>), [[COPY8]](p0) :: (store (<4 x s32>), align 32)
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aemerson wrote:

This seems like a regression? Unless we have a combine that simplifies the 2 x build_vector + concat_vector into a single wide build vector. What do you think?

https://github.com/llvm/llvm-project/pull/75223