[AMDGPU] Add tests for SIPreAllocateWWMRegs (#109963)

Author: optimisan

llvm/test/CodeGen/AMDGPU/si-pre-allocate-wwm-regs.mir

@@ -0,0 +1,49 @@
+# NOTE: Assertions have been autogenerated by utils/update_mir_test_checks.py UTC_ARGS: --version 5
+# RUN: llc -mtriple=amdgcn -mcpu=tahiti -verify-machineinstrs -run-pass=si-pre-allocate-wwm-regs -o - %s  | FileCheck %s
+# RUN: llc -mtriple=amdgcn -mcpu=tahiti -verify-machineinstrs -amdgpu-prealloc-sgpr-spill-vgprs -run-pass=si-pre-allocate-wwm-regs -o - %s | FileCheck %s --check-prefix=CHECK2
+
+# COM: auto-generated updates might remove checks for MachineFunctionInfo reserved registers.
+---
+
+name: pre_allocate_wwm_regs_strict
+tracksRegLiveness: true
+body: |
+  bb.0:
+    liveins: $sgpr1
+    ; CHECK-LABEL: name: pre_allocate_wwm_regs_strict
+    ; CHECK: wwmReservedRegs:
+    ; CHECK-NEXT: - '$vgpr0'
+    ; CHECK: liveins: $sgpr1
+    ; CHECK-NEXT: {{  $}}
+    ; CHECK-NEXT: [[DEF:%[0-9]+]]:vgpr_32 = IMPLICIT_DEF
+    ; CHECK-NEXT: renamable $sgpr4_sgpr5 = ENTER_STRICT_WWM -1, implicit-def $exec, implicit-def $scc, implicit $exec
+    ; CHECK-NEXT: $vgpr0 = V_MOV_B32_e32 0, implicit $exec
+    ; CHECK-NEXT: dead $vgpr0 = V_MOV_B32_dpp $vgpr0, [[DEF]], 323, 12, 15, 0, implicit $exec
+    ; CHECK-NEXT: $exec = EXIT_STRICT_WWM killed renamable $sgpr4_sgpr5
+    ; CHECK-NEXT: dead [[COPY:%[0-9]+]]:vgpr_32 = COPY [[DEF]]
+    %0:vgpr_32 = IMPLICIT_DEF
+    renamable $sgpr4_sgpr5 = ENTER_STRICT_WWM -1, implicit-def $exec, implicit-def $scc, implicit $exec
+    %1:vgpr_32 = V_MOV_B32_e32 0, implicit $exec
+    %2:vgpr_32 = V_MOV_B32_dpp %1, %0, 323, 12, 15, 0, implicit $exec
+    $exec = EXIT_STRICT_WWM killed renamable $sgpr4_sgpr5
+    %3:vgpr_32 = COPY %0
+...
+---
+
+name: pre_allocate_wwm_spill_to_vgpr
+tracksRegLiveness: true
+body: |
+  bb.0:
+    liveins: $sgpr1
+    ; CHECK2-LABEL: name: pre_allocate_wwm_spill_to_vgpr
+    ; CHECK2: wwmReservedRegs:
+    ; CHECK2-NEXT: - '$vgpr0'
+    ; CHECK2: liveins: $sgpr1
+    ; CHECK2-NEXT: {{  $}}
+    ; CHECK2-NEXT: [[DEF:%[0-9]+]]:vgpr_32 = IMPLICIT_DEF
+    ; CHECK2-NEXT: dead $vgpr0 = SI_SPILL_S32_TO_VGPR $sgpr1, 0, [[DEF]]
+    ; CHECK2-NEXT: dead [[COPY:%[0-9]+]]:vgpr_32 = COPY [[DEF]]
+    %0:vgpr_32 = IMPLICIT_DEF
+    %1:vgpr_32 = SI_SPILL_S32_TO_VGPR $sgpr1, 0, %0
+    %2:vgpr_32 = COPY %0
+...