# NOTE: Assertions have been autogenerated by utils/update_mir_test_checks.py
# RUN: llc -mtriple=amdgcn-amd-amdhsa -mcpu=gfx900 -run-pass=greedy -o - %s | FileCheck %s

# This testcase is restricted to use a maximum of 24 VGPRs. It is
# therefore possible to allocate a maximum of 3 vreg_256s at a
# time. The apparent number of registers in the class is larger, but
# each one overlaps with the next. Allocating a vreg_64 will prevent a
# full vreg_256 from being live at a given point.

# The hints are trying to force allocation of overlapping vreg_256s
# which cannot be satisfied. The last S_NOP in %bb.0 with 2 vreg_256s
# and a vreg_64 use can be satisfied as long as the hints are ignored.

# With the resulting allocation order, this ends up using last chance
# recoloring for a vreg_256. We should try to recolor for completed
# virtual registers with the same class, since the existing assignment
# can only be corrected by adjusting to a non-overlapping register.

--- |
  define void @recolor_impossible_hint() #0 {
    ret void
  }

  attributes #0 = { "amdgpu-waves-per-eu"="10,10" }
---

---
name:            recolor_impossible_hint
alignment:       1
tracksRegLiveness: true
registers:
  - { id: 0, class: vreg_256, preferred-register: '$vgpr0_vgpr1_vgpr2_vgpr3_vgpr4_vgpr5_vgpr6_vgpr7' }
  - { id: 1, class: vreg_256, preferred-register: '$vgpr1_vgpr2_vgpr3_vgpr4_vgpr5_vgpr6_vgpr7_vgpr8' }
  - { id: 2, class: vreg_256, preferred-register: '$vgpr2_vgpr3_vgpr4_vgpr5_vgpr6_vgpr7_vgpr8_vgpr9' }
  - { id: 3, class: vreg_256, preferred-register: '$vgpr3_vgpr4_vgpr5_vgpr6_vgpr7_vgpr8_vgpr9_vgpr10' }
machineFunctionInfo:
  scratchRSrcReg:  '$sgpr0_sgpr1_sgpr2_sgpr3'
  stackPtrOffsetReg: '$sgpr32'
  occupancy:       10
body:             |
  ; CHECK-LABEL: name: recolor_impossible_hint
  ; CHECK: bb.0:
  ; CHECK-NEXT:   successors: %bb.2(0x40000000), %bb.1(0x40000000)
  ; CHECK-NEXT: {{  $}}
  ; CHECK-NEXT:   S_NOP 0, implicit-def %7, implicit-def %19, implicit-def %5
  ; CHECK-NEXT:   SI_SPILL_V256_SAVE %19, %stack.3, $sgpr32, 0, implicit $exec :: (store (s256) into %stack.3, align 4, addrspace 5)
  ; CHECK-NEXT:   SI_SPILL_V256_SAVE %7, %stack.1, $sgpr32, 0, implicit $exec :: (store (s256) into %stack.1, align 4, addrspace 5)
  ; CHECK-NEXT:   SI_SPILL_V256_SAVE %5, %stack.0, $sgpr32, 0, implicit $exec :: (store (s256) into %stack.0, align 4, addrspace 5)
  ; CHECK-NEXT:   S_NOP 0, implicit-def %17
  ; CHECK-NEXT:   SI_SPILL_V256_SAVE %17, %stack.2, $sgpr32, 0, implicit $exec :: (store (s256) into %stack.2, align 4, addrspace 5)
  ; CHECK-NEXT:   S_NOP 0, implicit-def %4
  ; CHECK-NEXT:   [[SI_SPILL_V256_RESTORE:%[0-9]+]]:vreg_256 = SI_SPILL_V256_RESTORE %stack.1, $sgpr32, 0, implicit $exec :: (load (s256) from %stack.1, align 4, addrspace 5)
  ; CHECK-NEXT:   [[SI_SPILL_V256_RESTORE1:%[0-9]+]]:vreg_256 = SI_SPILL_V256_RESTORE %stack.3, $sgpr32, 0, implicit $exec :: (load (s256) from %stack.3, align 4, addrspace 5)
  ; CHECK-NEXT:   S_NOP 0, implicit [[SI_SPILL_V256_RESTORE]], implicit [[SI_SPILL_V256_RESTORE1]], implicit %4
  ; CHECK-NEXT:   [[COPY:%[0-9]+]]:vreg_256 = COPY [[SI_SPILL_V256_RESTORE1]]
  ; CHECK-NEXT:   S_CBRANCH_EXECNZ %bb.2, implicit $exec
  ; CHECK-NEXT: {{  $}}
  ; CHECK-NEXT: bb.1:
  ; CHECK-NEXT:   successors: %bb.2(0x80000000)
  ; CHECK-NEXT: {{  $}}
  ; CHECK-NEXT:   S_NOP 0, implicit [[COPY]]
  ; CHECK-NEXT:   [[SI_SPILL_V256_RESTORE2:%[0-9]+]]:vreg_256 = SI_SPILL_V256_RESTORE %stack.0, $sgpr32, 0, implicit $exec :: (load (s256) from %stack.0, align 4, addrspace 5)
  ; CHECK-NEXT:   S_NOP 0, implicit [[SI_SPILL_V256_RESTORE2]]
  ; CHECK-NEXT:   [[SI_SPILL_V256_RESTORE3:%[0-9]+]]:vreg_256 = SI_SPILL_V256_RESTORE %stack.2, $sgpr32, 0, implicit $exec :: (load (s256) from %stack.2, align 4, addrspace 5)
  ; CHECK-NEXT:   S_NOP 0, implicit [[SI_SPILL_V256_RESTORE3]]
  ; CHECK-NEXT: {{  $}}
  ; CHECK-NEXT: bb.2:
  ; CHECK-NEXT:   S_ENDPGM 0
  bb.0:
    S_NOP 0, implicit-def %0:vreg_256, implicit-def %1:vreg_256, implicit-def %2:vreg_256
    S_NOP 0, implicit-def %3:vreg_256
    S_NOP 0, implicit-def %4:vreg_64
    S_NOP 0, implicit %0, implicit %1, implicit %4
    S_CBRANCH_EXECNZ %bb.3, implicit $exec

  bb.2:
    S_NOP 0, implicit %1
    S_NOP 0, implicit %2
    S_NOP 0, implicit %3

  bb.3:
    S_ENDPGM 0

...