[llvm] AMDGPU: Delete redundant recursive copy handling code (PR #157032)

[Joe Nash via llvm-commits]

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@@ -207,3 +210,34 @@ body:             |
     $vgpr0 = COPY %4
     S_ENDPGM 0, implicit $vgpr0
 ...
+
+# Make sure the immediate materialized by the v_mov_b16 isn't
+# incorrectly folded into the bfi as 0.
+
+# FIXME: %4:vgpr_32 = COPY %3 is a direct copy from v16 to v32 and
+# should probably fail the verifier
+---
+name:            mov_v16_copy_v32_fold_b32_regression
+tracksRegLiveness: true
+body:             |
+  bb.0:
+    liveins: $vgpr0, $vgpr1
+
+    ; CHECK-LABEL: name: mov_v16_copy_v32_fold_b32_regression
+    ; CHECK: liveins: $vgpr0, $vgpr1
+    ; CHECK-NEXT: {{  $}}
+    ; CHECK-NEXT: [[COPY:%[0-9]+]]:vgpr_32 = COPY $vgpr1
+    ; CHECK-NEXT: [[COPY1:%[0-9]+]]:vgpr_32 = COPY $vgpr0
+    ; CHECK-NEXT: [[V_MOV_B16_t16_e64_:%[0-9]+]]:vgpr_16 = V_MOV_B16_t16_e64 0, 15360, 0, implicit $exec
+    ; CHECK-NEXT: [[COPY2:%[0-9]+]]:vgpr_32 = COPY [[V_MOV_B16_t16_e64_]]
+    ; CHECK-NEXT: [[V_BFI_B32_e64_:%[0-9]+]]:vgpr_32 = V_BFI_B32_e64 32767, [[COPY2]], [[COPY1]], implicit $exec
+    ; CHECK-NEXT: $vgpr0 = COPY [[V_BFI_B32_e64_]]
+    ; CHECK-NEXT: SI_RETURN implicit $vgpr0
+    %0:vgpr_32 = COPY $vgpr1
+    %1:vgpr_32 = COPY $vgpr0
+    %3:vgpr_16 = V_MOV_B16_t16_e64 0, 15360, 0, implicit $exec
+    %4:vgpr_32 = COPY %3
----------------
Sisyph wrote:

Yes this is illegal. I would consider it ill-formed input and not a suitable test. If this IR is generated, we should fix whatever is generating it.

https://github.com/llvm/llvm-project/pull/157032