RegAllocGreedy: Un-disable test in expensive_checks builds

This reverts a8f3eba. You need to
use -verify-regalloc to get a MachineVerifier run with LiveIntervals,
otherwise cases not covered by the basic liveness implementation
in the verifier are passed through (which covers most use of undefined
subrange errors).

llvm/test/CodeGen/AMDGPU/swdev502267-use-after-free-last-chance-recoloring-alloc-succeeds.mir

@@ -1,8 +1,5 @@
-# XFAIL: expensive_checks
-# FIXME: This fails the machine verifier after allocation
-
 # NOTE: Assertions have been autogenerated by utils/update_mir_test_checks.py UTC_ARGS: --version 5
-# RUN: llc -mtriple=amdgcn-amd-amdhsa -mcpu=gfx942 -stress-regalloc=4 -start-before=greedy,2 -stop-after=virtregrewriter,2 -o - %s | FileCheck %s
+# RUN: llc -mtriple=amdgcn-amd-amdhsa -mcpu=gfx942 -stress-regalloc=4 -verify-regalloc -start-before=greedy,2 -stop-after=virtregrewriter,2 -o - %s | FileCheck %s
 
 # This testcase hit a situation where greedy would hit a use after
 # free during last chance recoloring. This case successfully allocates
@@ -29,11 +26,12 @@ body:             |
   ; CHECK-NEXT:   renamable $vgpr5 = V_FMA_F32_e64 0, $vgpr7, 0, $vgpr7, 0, $vgpr2, 0, 0, implicit $mode, implicit $exec
   ; CHECK-NEXT:   SI_SPILL_AV128_SAVE $vgpr6_vgpr7_vgpr8_vgpr9, %stack.2, $sgpr32, 0, implicit $exec :: (store (s128) into %stack.2, align 4, addrspace 5)
   ; CHECK-NEXT:   renamable $vgpr6 = V_FMA_F32_e64 0, killed $vgpr8, 0, $vgpr8, 0, $vgpr1, 0, 0, implicit $mode, implicit $exec
+  ; CHECK-NEXT:   renamable $vgpr7 = IMPLICIT_DEF
   ; CHECK-NEXT:   S_CBRANCH_EXECZ %bb.2, implicit $exec
   ; CHECK-NEXT: {{  $}}
   ; CHECK-NEXT: bb.1:
   ; CHECK-NEXT:   successors: %bb.2(0x80000000)
-  ; CHECK-NEXT:   liveins: $vgpr0_vgpr1_vgpr2_vgpr3:0x00000000000000FF, $vgpr4_vgpr5_vgpr6_vgpr7:0x000000000000003F
+  ; CHECK-NEXT:   liveins: $vgpr0_vgpr1_vgpr2_vgpr3:0x00000000000000FF, $vgpr4_vgpr5_vgpr6_vgpr7:0x00000000000000FF
   ; CHECK-NEXT: {{  $}}
   ; CHECK-NEXT:   SI_SPILL_AV128_SAVE killed $vgpr0_vgpr1_vgpr2_vgpr3, %stack.1, $sgpr32, 0, implicit $exec :: (store (s128) into %stack.1, align 4, addrspace 5)
   ; CHECK-NEXT:   renamable $vgpr0_vgpr1_vgpr2_vgpr3 = SI_SPILL_V128_RESTORE %stack.2, $sgpr32, 0, implicit $exec :: (load (s128) from %stack.2, align 4, addrspace 5)
@@ -43,7 +41,7 @@ body:             |
   ; CHECK-NEXT:   SI_SPILL_V32_SAVE killed $vgpr0, %stack.3, $sgpr32, 0, implicit $exec :: (store (s32) into %stack.3, addrspace 5)
   ; CHECK-NEXT:   renamable $vgpr0 = IMPLICIT_DEF
   ; CHECK-NEXT:   renamable $vgpr2_vgpr3_vgpr4_vgpr5 = SI_SPILL_V128_RESTORE %stack.2, $sgpr32, 0, implicit $exec :: (load (s128) from %stack.2, align 4, addrspace 5)
-  ; CHECK-NEXT:   renamable $vgpr5 = nofpexcept V_DIV_FIXUP_F32_e64 0, killed $vgpr0, 0, undef $vgpr7, 0, killed $vgpr5, 0, 0, implicit $mode, implicit $exec
+  ; CHECK-NEXT:   renamable $vgpr5 = nofpexcept V_DIV_FIXUP_F32_e64 0, killed $vgpr0, 0, killed $vgpr7, 0, killed $vgpr5, 0, 0, implicit $mode, implicit $exec
   ; CHECK-NEXT:   renamable $vgpr0 = SI_SPILL_V32_RESTORE %stack.3, $sgpr32, 0, implicit $exec :: (load (s32) from %stack.3, addrspace 5)
   ; CHECK-NEXT:   renamable $vgpr9 = COPY killed renamable $vgpr5
   ; CHECK-NEXT:   renamable $vgpr4_vgpr5_vgpr6_vgpr7 = SI_SPILL_V128_RESTORE %stack.4, $sgpr32, 0, implicit $exec :: (load (s128) from %stack.4, align 4, addrspace 5)
@@ -76,6 +74,7 @@ body:             |
     undef %4.sub0:vreg_128_align2 = V_FMA_F32_e64 0, %3.sub0, 0, %3.sub0, 0, %0.sub3, 0, 0, implicit $mode, implicit $exec
     %4.sub1:vreg_128_align2 = V_FMA_F32_e64 0, %3.sub1, 0, %3.sub1, 0, %0.sub2, 0, 0, implicit $mode, implicit $exec
     %4.sub2:vreg_128_align2 = V_FMA_F32_e64 0, %3.sub2, 0, %3.sub2, 0, %0.sub1, 0, 0, implicit $mode, implicit $exec
+    %4.sub3:vreg_128_align2 = IMPLICIT_DEF
     S_CBRANCH_EXECZ %bb.2, implicit $exec
 
   bb.1: