[llvm] [AMDGPU] Add regbankselect rules for G_ADD/SUB and variants (PR #159860)

[Petar Avramovic via llvm-commits]

================
@@ -14,16 +14,12 @@ body: |
     ; CHECK-NEXT: {{  $}}
     ; CHECK-NEXT: [[COPY:%[0-9]+]]:sgpr(<2 x s16>) = COPY $sgpr0
     ; CHECK-NEXT: [[COPY1:%[0-9]+]]:sgpr(<2 x s16>) = COPY $sgpr1
-    ; CHECK-NEXT: [[BITCAST:%[0-9]+]]:sgpr(s32) = G_BITCAST [[COPY]](<2 x s16>)
-    ; CHECK-NEXT: [[C:%[0-9]+]]:sgpr(s32) = G_CONSTANT i32 16
-    ; CHECK-NEXT: [[LSHR:%[0-9]+]]:sgpr(s32) = G_LSHR [[BITCAST]], [[C]](s32)
-    ; CHECK-NEXT: [[BITCAST1:%[0-9]+]]:sgpr(s32) = G_BITCAST [[COPY1]](<2 x s16>)
-    ; CHECK-NEXT: [[C1:%[0-9]+]]:sgpr(s32) = G_CONSTANT i32 16
-    ; CHECK-NEXT: [[LSHR1:%[0-9]+]]:sgpr(s32) = G_LSHR [[BITCAST1]], [[C1]](s32)
-    ; CHECK-NEXT: [[ADD:%[0-9]+]]:sgpr(s32) = G_ADD [[BITCAST]], [[BITCAST1]]
-    ; CHECK-NEXT: [[ADD1:%[0-9]+]]:sgpr(s32) = G_ADD [[LSHR]], [[LSHR1]]
-    ; CHECK-NEXT: [[BUILD_VECTOR_TRUNC:%[0-9]+]]:sgpr(<2 x s16>) = G_BUILD_VECTOR_TRUNC [[ADD]](s32), [[ADD1]](s32)
-    ; CHECK-NEXT: S_ENDPGM 0, implicit [[BUILD_VECTOR_TRUNC]](<2 x s16>)
----------------
petar-avramovic wrote:

this is correct

https://github.com/llvm/llvm-project/pull/159860