[AMDGPU] Add export clustering post-RA scheduler test (NFC) (#141400)

This is a pre-commit test for #141399.

Author: perlfu

llvm/test/CodeGen/AMDGPU/export-cluster-postra.mir

@@ -0,0 +1,46 @@
+# NOTE: Assertions have been autogenerated by utils/update_mir_test_checks.py UTC_ARGS: --version 5
+# RUN: llc -mtriple=amdgcn -mcpu=gfx1100 -passes=postmisched %s -o - | FileCheck %s
+
+--- |
+  define amdgpu_ps void @export_cluster_postra() {
+    ret void
+  }
+...
+---
+
+---
+name:            export_cluster_postra
+body: |
+  bb.0:
+    liveins: $vgpr0, $vgpr1, $vgpr2, $vgpr3, $sgpr4, $vgpr5, $vgpr6, $sgpr8_sgpr9_sgpr10_sgpr11
+
+    ; CHECK-LABEL: name: export_cluster_postra
+    ; CHECK: liveins: $vgpr0, $vgpr1, $vgpr2, $vgpr3, $sgpr4, $vgpr5, $vgpr6, $sgpr8_sgpr9_sgpr10_sgpr11
+    ; CHECK-NEXT: {{  $}}
+    ; CHECK-NEXT: BUNDLE implicit-def $sgpr0, implicit-def $sgpr1, implicit killed $sgpr8_sgpr9_sgpr10_sgpr11 {
+    ; CHECK-NEXT:   $sgpr0 = S_BUFFER_LOAD_DWORD_IMM $sgpr8_sgpr9_sgpr10_sgpr11, 20, 0 :: (dereferenceable invariant load (s32))
+    ; CHECK-NEXT:   $sgpr1 = S_BUFFER_LOAD_DWORD_IMM killed $sgpr8_sgpr9_sgpr10_sgpr11, 28, 0 :: (dereferenceable invariant load (s32))
+    ; CHECK-NEXT: }
+    ; CHECK-NEXT: $vgpr6 = nofpexcept V_CVT_PKRTZ_F16_F32_e64 0, killed $vgpr6, 0, 1065353216, 0, 0, implicit $mode, implicit $exec
+    ; CHECK-NEXT: $vgpr5 = nofpexcept V_CVT_PKRTZ_F16_F32_e64 0, killed $vgpr5, 0, 1065353216, 0, 0, implicit $mode, implicit $exec
+    ; CHECK-NEXT: EXP 0, killed $vgpr0, killed $vgpr6, undef $vgpr0, undef $vgpr0, -1, 0, 3, implicit $exec
+    ; CHECK-NEXT: EXP 1, killed $vgpr1, killed $vgpr5, undef $vgpr0, undef $vgpr0, -1, 0, 3, implicit $exec
+    ; CHECK-NEXT: $vgpr7 = nnan nsz arcp contract afn reassoc nofpexcept V_MUL_F32_e32 killed $sgpr0, $vgpr2, implicit $mode, implicit $exec
+    ; CHECK-NEXT: $vgpr2 = nnan nsz arcp contract afn reassoc nofpexcept V_ADD_F32_e64 0, killed $vgpr2, 0, killed $sgpr1, 1, 0, implicit $mode, implicit $exec
+    ; CHECK-NEXT: $vgpr3 = nofpexcept V_CVT_PKRTZ_F16_F32_e32 killed $vgpr7, killed $vgpr3, implicit $mode, implicit $exec
+    ; CHECK-NEXT: $vgpr2 = nofpexcept V_CVT_PKRTZ_F16_F32_e32 killed $vgpr4, killed $vgpr2, implicit $mode, implicit $exec
+    ; CHECK-NEXT: EXP_DONE 2, killed $vgpr3, killed $vgpr2, undef $vgpr0, undef $vgpr0, -1, 0, 3, implicit $exec
+    BUNDLE implicit-def $sgpr0, implicit-def $sgpr1, implicit $sgpr8_sgpr9_sgpr10_sgpr11 {
+      $sgpr0 = S_BUFFER_LOAD_DWORD_IMM $sgpr8_sgpr9_sgpr10_sgpr11, 20, 0 :: (dereferenceable invariant load (s32))
+      $sgpr1 = S_BUFFER_LOAD_DWORD_IMM $sgpr8_sgpr9_sgpr10_sgpr11, 28, 0 :: (dereferenceable invariant load (s32))
+    }
+    $vgpr6 = nofpexcept V_CVT_PKRTZ_F16_F32_e64 0, $vgpr6, 0, 1065353216, 0, 0, implicit $mode, implicit $exec
+    $vgpr5 = nofpexcept V_CVT_PKRTZ_F16_F32_e64 0, $vgpr5, 0, 1065353216, 0, 0, implicit $mode, implicit $exec
+    $vgpr7 = nnan nsz arcp contract afn reassoc nofpexcept V_MUL_F32_e32 $sgpr0, $vgpr2, implicit $mode, implicit $exec
+    $vgpr3 = nofpexcept V_CVT_PKRTZ_F16_F32_e32 $vgpr7, $vgpr3, implicit $mode, implicit $exec
+    $vgpr2 = nnan nsz arcp contract afn reassoc nofpexcept V_ADD_F32_e64 0, $vgpr2, 0, $sgpr1, 1, 0, implicit $mode, implicit $exec
+    $vgpr2 = nofpexcept V_CVT_PKRTZ_F16_F32_e32 $vgpr4, $vgpr2, implicit $mode, implicit $exec
+    EXP 0, $vgpr0, $vgpr6, undef $vgpr0, undef $vgpr0, -1, 0, 3, implicit $exec
+    EXP 1, $vgpr1, $vgpr5, undef $vgpr0, undef $vgpr0, -1, 0, 3, implicit $exec
+    EXP_DONE 2, $vgpr3, $vgpr2, undef $vgpr0, undef $vgpr0, -1, 0, 3, implicit $exec
+...