llvm/test/CodeGen/AMDGPU/collapse-endcf.mir

# NOTE: Assertions have been autogenerated by utils/update_mir_test_checks.py
# RUN: llc -march=amdgcn -verify-machineinstrs -run-pass=si-lower-control-flow -amdgpu-remove-redundant-endcf %s -o - | FileCheck -check-prefix=GCN %s

# Make sure dbg_value doesn't change codeegn when collapsing end_cf
---
name: simple_nested_if_dbg_value
tracksRegLiveness: true
machineFunctionInfo:
  isEntryFunction: true
body:             |
  ; GCN-LABEL: name: simple_nested_if_dbg_value
  ; GCN: bb.0:
  ; GCN:   successors: %bb.1(0x40000000), %bb.4(0x40000000)
  ; GCN:   [[COPY:%[0-9]+]]:sreg_64 = COPY $exec, implicit-def $exec
  ; GCN:   [[S_AND_B64_:%[0-9]+]]:sreg_64 = S_AND_B64 [[COPY]], undef %1:sreg_64, implicit-def dead $scc
  ; GCN:   $exec = S_MOV_B64_term killed [[S_AND_B64_]]
  ; GCN:   S_CBRANCH_EXECZ %bb.4, implicit $exec
  ; GCN: bb.1:
  ; GCN:   successors: %bb.2(0x40000000), %bb.4(0x40000000)
  ; GCN:   [[COPY1:%[0-9]+]]:sreg_64 = COPY $exec, implicit-def $exec
  ; GCN:   [[S_AND_B64_1:%[0-9]+]]:sreg_64 = S_AND_B64 [[COPY1]], undef %3:sreg_64, implicit-def dead $scc
  ; GCN:   $exec = S_MOV_B64_term killed [[S_AND_B64_1]]
  ; GCN:   S_CBRANCH_EXECZ %bb.4, implicit $exec
  ; GCN: bb.2:
  ; GCN:   successors: %bb.4(0x80000000)
  ; GCN: bb.4:
  ; GCN:   $exec = S_OR_B64 $exec, [[COPY]], implicit-def $scc
  ; GCN:   DBG_VALUE
  ; GCN:   S_ENDPGM 0
  bb.0:
    successors: %bb.1, %bb.4

    %0:sreg_64 = SI_IF undef %1:sreg_64, %bb.4, implicit-def dead $exec, implicit-def dead $scc, implicit $exec

  bb.1:
    successors: %bb.2, %bb.3

    %2:sreg_64 = SI_IF undef %3:sreg_64, %bb.3, implicit-def dead $exec, implicit-def dead $scc, implicit $exec

  bb.2:

  bb.3:
    SI_END_CF %2:sreg_64, implicit-def dead $exec, implicit-def dead $scc, implicit $exec
    DBG_VALUE

  bb.4:
    DBG_VALUE
    SI_END_CF %0:sreg_64, implicit-def dead $exec, implicit-def dead $scc, implicit $exec
    S_ENDPGM 0

...

# Empty block separates the collapsable s_or_b64
---
name: simple_nested_if_empty_block_between
tracksRegLiveness: true
machineFunctionInfo:
  isEntryFunction: true
body:             |
  ; GCN-LABEL: name: simple_nested_if_empty_block_between
  ; GCN: bb.0:
  ; GCN:   successors: %bb.5(0x40000000), %bb.1(0x40000000)
  ; GCN:   [[COPY:%[0-9]+]]:sreg_64 = COPY $exec, implicit-def $exec
  ; GCN:   [[S_AND_B64_:%[0-9]+]]:sreg_64 = S_AND_B64 [[COPY]], undef %1:sreg_64, implicit-def dead $scc
  ; GCN:   $exec = S_MOV_B64_term killed [[S_AND_B64_]]
  ; GCN:   S_CBRANCH_EXECZ %bb.5, implicit $exec
  ; GCN: bb.1:
  ; GCN:   successors: %bb.2(0x40000000), %bb.4(0x40000000)
  ; GCN:   [[COPY1:%[0-9]+]]:sreg_64 = COPY $exec, implicit-def $exec
  ; GCN:   [[S_AND_B64_1:%[0-9]+]]:sreg_64 = S_AND_B64 [[COPY1]], undef %3:sreg_64, implicit-def dead $scc
  ; GCN:   $exec = S_MOV_B64_term killed [[S_AND_B64_1]]
  ; GCN:   S_CBRANCH_EXECZ %bb.4, implicit $exec
  ; GCN: bb.2:
  ; GCN:   successors: %bb.4(0x80000000)
  ; GCN: bb.4:
  ; GCN:   successors: %bb.5(0x80000000)
  ; GCN: bb.5:
  ; GCN:   $exec = S_OR_B64 $exec, [[COPY]], implicit-def $scc
  ; GCN:   S_ENDPGM 0
  bb.0:
    %0:sreg_64 = SI_IF undef %1:sreg_64, %bb.4, implicit-def dead $exec, implicit-def dead $scc, implicit $exec

  bb.1:
    successors: %bb.2, %bb.3

    %2:sreg_64 = SI_IF undef %3:sreg_64, %bb.3, implicit-def dead $exec, implicit-def dead $scc, implicit $exec

  bb.2:

  bb.3:
    SI_END_CF %2:sreg_64, implicit-def dead $exec, implicit-def dead $scc, implicit $exec

  bb.5:

  bb.4:
    SI_END_CF %0:sreg_64, implicit-def dead $exec, implicit-def dead $scc, implicit $exec
    S_ENDPGM 0

...

# Effectively empty block separates the collapsable s_or_b64
---
name: simple_nested_if_empty_block_dbg_between
tracksRegLiveness: true
machineFunctionInfo:
  isEntryFunction: true
body:             |
  ; GCN-LABEL: name: simple_nested_if_empty_block_dbg_between
  ; GCN: bb.0:
  ; GCN:   successors: %bb.1(0x40000000), %bb.5(0x40000000)
  ; GCN:   [[COPY:%[0-9]+]]:sreg_64 = COPY $exec, implicit-def $exec
  ; GCN:   [[S_AND_B64_:%[0-9]+]]:sreg_64 = S_AND_B64 [[COPY]], undef %1:sreg_64, implicit-def dead $scc
  ; GCN:   $exec = S_MOV_B64_term killed [[S_AND_B64_]]
  ; GCN:   S_CBRANCH_EXECZ %bb.5, implicit $exec
  ; GCN: bb.1:
  ; GCN:   successors: %bb.2(0x40000000), %bb.4(0x40000000)
  ; GCN:   [[COPY1:%[0-9]+]]:sreg_64 = COPY $exec, implicit-def $exec
  ; GCN:   [[S_AND_B64_1:%[0-9]+]]:sreg_64 = S_AND_B64 [[COPY1]], undef %3:sreg_64, implicit-def dead $scc
  ; GCN:   $exec = S_MOV_B64_term killed [[S_AND_B64_1]]
  ; GCN:   S_CBRANCH_EXECZ %bb.4, implicit $exec
  ; GCN: bb.2:
  ; GCN:   successors: %bb.4(0x80000000)
  ; GCN: bb.4:
  ; GCN:   successors: %bb.5(0x80000000)
  ; GCN:   DBG_VALUE
  ; GCN: bb.5:
  ; GCN:   $exec = S_OR_B64 $exec, [[COPY]], implicit-def $scc
  ; GCN:   S_ENDPGM 0
  bb.0:
    successors: %bb.1, %bb.4

    %0:sreg_64 = SI_IF undef %1:sreg_64, %bb.4, implicit-def dead $exec, implicit-def dead $scc, implicit $exec

  bb.1:
    successors: %bb.2, %bb.3

    %2:sreg_64 = SI_IF undef %3:sreg_64, %bb.3, implicit-def dead $exec, implicit-def dead $scc, implicit $exec

  bb.2:

  bb.3:
    SI_END_CF %2:sreg_64, implicit-def dead $exec, implicit-def dead $scc, implicit $exec

  bb.5:
    DBG_VALUE

  bb.4:
    SI_END_CF %0:sreg_64, implicit-def dead $exec, implicit-def dead $scc, implicit $exec
    S_ENDPGM 0

...

---
name: skip_salu_and_meta_insts_find_first
tracksRegLiveness: true
machineFunctionInfo:
  isEntryFunction: true
body:             |
  ; GCN-LABEL: name: skip_salu_and_meta_insts_find_first
  ; GCN: bb.0:
  ; GCN:   successors: %bb.1(0x40000000), %bb.4(0x40000000)
  ; GCN:   liveins: $vgpr0, $sgpr0_sgpr1
  ; GCN:   [[COPY:%[0-9]+]]:sreg_64 = COPY $exec, implicit-def $exec
  ; GCN:   [[S_AND_B64_:%[0-9]+]]:sreg_64 = S_AND_B64 [[COPY]], undef %1:sreg_64, implicit-def dead $scc
  ; GCN:   $exec = S_MOV_B64_term killed [[S_AND_B64_]]
  ; GCN:   S_CBRANCH_EXECZ %bb.4, implicit $exec
  ; GCN: bb.1:
  ; GCN:   successors: %bb.2(0x40000000), %bb.3(0x40000000)
  ; GCN:   [[COPY1:%[0-9]+]]:sreg_64 = COPY $exec, implicit-def $exec
  ; GCN:   [[S_AND_B64_1:%[0-9]+]]:sreg_64 = S_AND_B64 [[COPY1]], undef %3:sreg_64, implicit-def dead $scc
  ; GCN:   $exec = S_MOV_B64_term killed [[S_AND_B64_1]]
  ; GCN:   S_CBRANCH_EXECZ %bb.3, implicit $exec
  ; GCN: bb.2:
  ; GCN:   successors: %bb.3(0x80000000)
  ; GCN: bb.3:
  ; GCN:   successors: %bb.4(0x80000000)
  ; GCN:   [[DEF:%[0-9]+]]:sgpr_32 = IMPLICIT_DEF
  ; GCN:   [[S_BREV_B32_:%[0-9]+]]:sgpr_32 = S_BREV_B32 [[DEF]]
  ; GCN:   KILL [[DEF]]
  ; GCN: bb.4:
  ; GCN:   $exec = S_OR_B64 $exec, [[COPY]], implicit-def $scc
  ; GCN:   S_ENDPGM 0
  bb.0:
    successors: %bb.1, %bb.4
    liveins: $vgpr0, $sgpr0_sgpr1

    %0:sreg_64 = SI_IF undef %1:sreg_64, %bb.4, implicit-def dead $exec, implicit-def dead $scc, implicit $exec

  bb.1:
    successors: %bb.2, %bb.3

    %2:sreg_64 = SI_IF undef %3:sreg_64, %bb.3, implicit-def dead $exec, implicit-def dead $scc, implicit $exec

  bb.2:

  bb.3:
    %4:sgpr_32 = IMPLICIT_DEF
    %5:sgpr_32 = S_BREV_B32 %4
    KILL %4
    SI_END_CF %2:sreg_64, implicit-def dead $exec, implicit-def dead $scc, implicit $exec

  bb.4:
    SI_END_CF %0:sreg_64, implicit-def dead $exec, implicit-def dead $scc, implicit $exec
    S_ENDPGM 0

...

# Make sure SALU instructions, meta instructions, and SGPR->SGPR
# copies are skipped.
---
name: skip_salu_and_meta_insts_after
tracksRegLiveness: true
machineFunctionInfo:
  isEntryFunction: true
body:             |
  ; GCN-LABEL: name: skip_salu_and_meta_insts_after
  ; GCN: bb.0:
  ; GCN:   successors: %bb.1(0x40000000), %bb.4(0x40000000)
  ; GCN:   [[COPY:%[0-9]+]]:sreg_64 = COPY $exec, implicit-def $exec
  ; GCN:   [[S_AND_B64_:%[0-9]+]]:sreg_64 = S_AND_B64 [[COPY]], undef %1:sreg_64, implicit-def dead $scc
  ; GCN:   $exec = S_MOV_B64_term killed [[S_AND_B64_]]
  ; GCN:   S_CBRANCH_EXECZ %bb.4, implicit $exec
  ; GCN: bb.1:
  ; GCN:   successors: %bb.2(0x40000000), %bb.3(0x40000000)
  ; GCN:   [[COPY1:%[0-9]+]]:sreg_64 = COPY $exec, implicit-def $exec
  ; GCN:   [[S_AND_B64_1:%[0-9]+]]:sreg_64 = S_AND_B64 [[COPY1]], undef %3:sreg_64, implicit-def dead $scc
  ; GCN:   $exec = S_MOV_B64_term killed [[S_AND_B64_1]]
  ; GCN:   S_CBRANCH_EXECZ %bb.3, implicit $exec
  ; GCN: bb.2:
  ; GCN:   successors: %bb.3(0x80000000)
  ; GCN: bb.3:
  ; GCN:   successors: %bb.4(0x80000000)
  ; GCN:   [[DEF:%[0-9]+]]:sgpr_32 = IMPLICIT_DEF
  ; GCN:   [[S_BREV_B32_:%[0-9]+]]:sgpr_32 = S_BREV_B32 [[DEF]]
  ; GCN:   KILL [[DEF]]
  ; GCN:   [[COPY2:%[0-9]+]]:sgpr_32 = COPY [[S_BREV_B32_]]
  ; GCN: bb.4:
  ; GCN:   $exec = S_OR_B64 $exec, [[COPY]], implicit-def $scc
  ; GCN:   S_ENDPGM 0
  bb.0:
    successors: %bb.1, %bb.4

    %0:sreg_64 = SI_IF undef %1:sreg_64, %bb.4, implicit-def dead $exec, implicit-def dead $scc, implicit $exec

  bb.1:
    successors: %bb.2, %bb.3

    %2:sreg_64 = SI_IF undef %3:sreg_64, %bb.3, implicit-def dead $exec, implicit-def dead $scc, implicit $exec

  bb.2:

  bb.3:
    SI_END_CF %2:sreg_64, implicit-def dead $exec, implicit-def dead $scc, implicit $exec
    %4:sgpr_32 = IMPLICIT_DEF
    %5:sgpr_32 = S_BREV_B32 %4
    KILL %4
    %6:sgpr_32 = COPY %5

  bb.4:
    SI_END_CF %0:sreg_64, implicit-def dead $exec, implicit-def dead $scc, implicit $exec
    S_ENDPGM 0

...

# SALU instruction depends on exec through a normal operand.
---
name: salu_exec_dependency
tracksRegLiveness: true
machineFunctionInfo:
  isEntryFunction: true
body:             |
  ; GCN-LABEL: name: salu_exec_dependency
  ; GCN: bb.0:
  ; GCN:   successors: %bb.1(0x40000000), %bb.4(0x40000000)
  ; GCN:   [[COPY:%[0-9]+]]:sreg_64 = COPY $exec, implicit-def $exec
  ; GCN:   [[S_AND_B64_:%[0-9]+]]:sreg_64 = S_AND_B64 [[COPY]], undef %1:sreg_64, implicit-def dead $scc
  ; GCN:   $exec = S_MOV_B64_term killed [[S_AND_B64_]]
  ; GCN:   S_CBRANCH_EXECZ %bb.4, implicit $exec
  ; GCN: bb.1:
  ; GCN:   successors: %bb.2(0x40000000), %bb.3(0x40000000)
  ; GCN:   [[COPY1:%[0-9]+]]:sreg_64 = COPY $exec, implicit-def $exec
  ; GCN:   [[S_AND_B64_1:%[0-9]+]]:sreg_64 = S_AND_B64 [[COPY1]], undef %3:sreg_64, implicit-def dead $scc
  ; GCN:   $exec = S_MOV_B64_term killed [[S_AND_B64_1]]
  ; GCN:   S_CBRANCH_EXECZ %bb.3, implicit $exec
  ; GCN: bb.2:
  ; GCN:   successors: %bb.3(0x80000000)
  ; GCN: bb.3:
  ; GCN:   successors: %bb.4(0x80000000)
  ; GCN:   $exec = S_OR_B64 $exec, [[COPY1]], implicit-def $scc
  ; GCN:   [[S_BREV_B64_:%[0-9]+]]:sreg_64 = S_BREV_B64 $exec
  ; GCN: bb.4:
  ; GCN:   $exec = S_OR_B64 $exec, [[COPY]], implicit-def $scc
  ; GCN:   S_ENDPGM 0
  bb.0:
    successors: %bb.1, %bb.4

    %0:sreg_64 = SI_IF undef %1:sreg_64, %bb.4, implicit-def dead $exec, implicit-def dead $scc, implicit $exec

  bb.1:
    successors: %bb.2, %bb.3

    %2:sreg_64 = SI_IF undef %3:sreg_64, %bb.3, implicit-def dead $exec, implicit-def dead $scc, implicit $exec

  bb.2:

  bb.3:
    SI_END_CF %2:sreg_64, implicit-def dead $exec, implicit-def dead $scc, implicit $exec
    %4:sreg_64 = S_BREV_B64 $exec

  bb.4:
    SI_END_CF %0:sreg_64, implicit-def dead $exec, implicit-def dead $scc, implicit $exec
    S_ENDPGM 0

...

# Copy to / from VGPR should be assumed to read exec
---
name: copy_no_explicit_exec_dependency
tracksRegLiveness: true
machineFunctionInfo:
  isEntryFunction: true
body:             |
  ; GCN-LABEL: name: copy_no_explicit_exec_dependency
  ; GCN: bb.0:
  ; GCN:   successors: %bb.1(0x40000000), %bb.4(0x40000000)
  ; GCN:   [[COPY:%[0-9]+]]:sreg_64 = COPY $exec, implicit-def $exec
  ; GCN:   [[S_AND_B64_:%[0-9]+]]:sreg_64 = S_AND_B64 [[COPY]], undef %1:sreg_64, implicit-def dead $scc
  ; GCN:   $exec = S_MOV_B64_term killed [[S_AND_B64_]]
  ; GCN:   S_CBRANCH_EXECZ %bb.4, implicit $exec
  ; GCN: bb.1:
  ; GCN:   successors: %bb.2(0x40000000), %bb.3(0x40000000)
  ; GCN:   [[DEF:%[0-9]+]]:vreg_128 = IMPLICIT_DEF
  ; GCN:   [[COPY1:%[0-9]+]]:sreg_64 = COPY $exec, implicit-def $exec
  ; GCN:   [[S_AND_B64_1:%[0-9]+]]:sreg_64 = S_AND_B64 [[COPY1]], undef %4:sreg_64, implicit-def dead $scc
  ; GCN:   $exec = S_MOV_B64_term killed [[S_AND_B64_1]]
  ; GCN:   S_CBRANCH_EXECZ %bb.3, implicit $exec
  ; GCN: bb.2:
  ; GCN:   successors: %bb.3(0x80000000)
  ; GCN: bb.3:
  ; GCN:   successors: %bb.4(0x80000000)
  ; GCN:   $exec = S_OR_B64 $exec, [[COPY1]], implicit-def $scc
  ; GCN:   [[COPY2:%[0-9]+]]:vgpr_32 = COPY [[DEF]].sub2
  ; GCN: bb.4:
  ; GCN:   $exec = S_OR_B64 $exec, [[COPY]], implicit-def $scc
  ; GCN:   S_ENDPGM 0
  bb.0:
    successors: %bb.1, %bb.4

    %0:sreg_64 = SI_IF undef %1:sreg_64, %bb.4, implicit-def dead $exec, implicit-def dead $scc, implicit $exec

  bb.1:
    successors: %bb.2, %bb.3

    %2:vreg_128 = IMPLICIT_DEF
    %3:sreg_64 = SI_IF undef %4:sreg_64, %bb.3, implicit-def dead $exec, implicit-def dead $scc, implicit $exec

  bb.2:

  bb.3:
    SI_END_CF %3:sreg_64, implicit-def dead $exec, implicit-def dead $scc, implicit $exec
    %5:vgpr_32 = COPY %2.sub2

  bb.4:
    SI_END_CF %0:sreg_64, implicit-def dead $exec, implicit-def dead $scc, implicit $exec
    S_ENDPGM 0

...

---
name: simple_nested_if_not_layout_successor
tracksRegLiveness: true
machineFunctionInfo:
  isEntryFunction: true
body:             |
  ; GCN-LABEL: name: simple_nested_if_not_layout_successor
  ; GCN: bb.0:
  ; GCN:   successors: %bb.1(0x40000000), %bb.4(0x40000000)
  ; GCN:   [[COPY:%[0-9]+]]:sreg_64 = COPY $exec, implicit-def $exec
  ; GCN:   [[S_AND_B64_:%[0-9]+]]:sreg_64 = S_AND_B64 [[COPY]], undef %1:sreg_64, implicit-def dead $scc
  ; GCN:   $exec = S_MOV_B64_term killed [[S_AND_B64_]]
  ; GCN:   S_CBRANCH_EXECZ %bb.4, implicit $exec
  ; GCN: bb.1:
  ; GCN:   successors: %bb.2(0x40000000), %bb.5(0x40000000)
  ; GCN:   [[COPY1:%[0-9]+]]:sreg_64 = COPY $exec, implicit-def $exec
  ; GCN:   [[S_AND_B64_1:%[0-9]+]]:sreg_64 = S_AND_B64 [[COPY1]], undef %3:sreg_64, implicit-def dead $scc
  ; GCN:   $exec = S_MOV_B64_term killed [[S_AND_B64_1]]
  ; GCN:   S_CBRANCH_EXECZ %bb.5, implicit $exec
  ; GCN: bb.2:
  ; GCN:   successors: %bb.5(0x80000000)
  ; GCN: bb.5:
  ; GCN:   successors: %bb.4(0x80000000)
  ; GCN:   S_BRANCH %bb.4
  ; GCN: bb.4:
  ; GCN:   $exec = S_OR_B64 $exec, [[COPY]], implicit-def $scc
  ; GCN:   S_ENDPGM 0
  bb.0:
    successors: %bb.1, %bb.4

    %0:sreg_64 = SI_IF undef %1:sreg_64, %bb.4, implicit-def dead $exec, implicit-def dead $scc, implicit $exec

  bb.1:
    successors: %bb.2, %bb.3

    %2:sreg_64 = SI_IF undef %3:sreg_64, %bb.3, implicit-def dead $exec, implicit-def dead $scc, implicit $exec

  bb.2:

  bb.3:
    SI_END_CF %2:sreg_64, implicit-def dead $exec, implicit-def dead $scc, implicit $exec
    S_BRANCH %bb.5

  bb.4:
    SI_END_CF %0:sreg_64, implicit-def dead $exec, implicit-def dead $scc, implicit $exec
    S_ENDPGM 0

  bb.5:
    S_BRANCH %bb.4

...

# This should never happen, but check that we do not hang anyway

---
name: resursive_endcf
tracksRegLiveness: true
liveins:
  - { reg: '$vgpr0', virtual-reg: '%0' }
machineFunctionInfo:
  isEntryFunction: true
body:             |
  ; GCN-LABEL: name: resursive_endcf
  ; GCN: bb.0:
  ; GCN:   successors: %bb.1(0x80000000)
  ; GCN:   liveins: $vgpr0
  ; GCN:   [[COPY:%[0-9]+]]:vgpr_32 = COPY $vgpr0
  ; GCN:   [[V_CMP_LT_U32_e64_:%[0-9]+]]:sreg_64 = V_CMP_LT_U32_e64 1, [[COPY]], implicit $exec
  ; GCN: bb.1:
  ; GCN:   successors: %bb.1(0x80000000)
  ; GCN:   $exec = S_OR_B64 $exec, [[V_CMP_LT_U32_e64_]], implicit-def $scc
  ; GCN:   S_BRANCH %bb.1
  bb.0:
    successors: %bb.1
    liveins: $vgpr0

    %0:vgpr_32 = COPY $vgpr0
    %2:sreg_64 = V_CMP_LT_U32_e64 1, %0, implicit $exec

  bb.1:
    successors: %bb.1

    SI_END_CF %2:sreg_64, implicit-def dead $exec, implicit-def dead $scc, implicit $exec
    S_BRANCH %bb.1

...

# Both s_or_b64 shall be preserved since the outer SI_END_CF belongs to SI_ELSE.

---
name: simple_outer_if_else
tracksRegLiveness: true
machineFunctionInfo:
  isEntryFunction: true
body:             |
  ; GCN-LABEL: name: simple_outer_if_else
  ; GCN: bb.0:
  ; GCN:   successors: %bb.1(0x40000000), %bb.2(0x40000000)
  ; GCN:   [[COPY:%[0-9]+]]:sreg_64 = COPY $exec, implicit-def $exec
  ; GCN:   [[S_AND_B64_:%[0-9]+]]:sreg_64 = S_AND_B64 [[COPY]], undef %1:sreg_64, implicit-def dead $scc
  ; GCN:   [[S_XOR_B64_:%[0-9]+]]:sreg_64 = S_XOR_B64 [[S_AND_B64_]], [[COPY]], implicit-def dead $scc
  ; GCN:   $exec = S_MOV_B64_term killed [[S_AND_B64_]]
  ; GCN:   S_CBRANCH_EXECZ %bb.2, implicit $exec
  ; GCN: bb.1:
  ; GCN:   successors: %bb.2(0x80000000)
  ; GCN:   S_BRANCH %bb.2
  ; GCN: bb.2:
  ; GCN:   successors: %bb.3(0x40000000), %bb.6(0x40000000)
  ; GCN:   [[S_OR_SAVEEXEC_B64_:%[0-9]+]]:sreg_64 = S_OR_SAVEEXEC_B64 [[S_XOR_B64_]], implicit-def $exec, implicit-def $scc, implicit $exec
  ; GCN:   [[S_AND_B64_1:%[0-9]+]]:sreg_64 = S_AND_B64 $exec, [[S_OR_SAVEEXEC_B64_]], implicit-def $scc
  ; GCN:   $exec = S_XOR_B64_term $exec, [[S_AND_B64_1]], implicit-def $scc
  ; GCN:   S_CBRANCH_EXECZ %bb.6, implicit $exec
  ; GCN: bb.3:
  ; GCN:   successors: %bb.3(0x40000000), %bb.4(0x40000000)
  ; GCN:   [[COPY1:%[0-9]+]]:sreg_64 = COPY $exec, implicit-def $exec
  ; GCN:   [[S_AND_B64_2:%[0-9]+]]:sreg_64 = S_AND_B64 [[COPY1]], undef %4:sreg_64, implicit-def dead $scc
  ; GCN:   $exec = S_MOV_B64_term killed [[S_AND_B64_2]]
  ; GCN:   S_CBRANCH_EXECZ %bb.3, implicit $exec
  ; GCN: bb.4:
  ; GCN:   successors: %bb.5(0x80000000)
  ; GCN: bb.5:
  ; GCN:   successors: %bb.6(0x80000000)
  ; GCN:   $exec = S_OR_B64 $exec, [[COPY1]], implicit-def $scc
  ; GCN: bb.6:
  ; GCN:   $exec = S_OR_B64 $exec, [[S_AND_B64_1]], implicit-def $scc
  ; GCN:   S_ENDPGM 0
  bb.0:
    successors: %bb.1, %bb.2

    %0:sreg_64 = SI_IF undef %1:sreg_64, %bb.2, implicit-def dead $exec, implicit-def dead $scc, implicit $exec

  bb.1:
    successors: %bb.2
    S_BRANCH %bb.2

  bb.2:
    successors: %bb.3, %bb.6
    %2:sreg_64 = SI_ELSE %0:sreg_64, %bb.6, implicit-def dead $exec, implicit-def dead $scc, implicit $exec

  bb.3:
    successors: %bb.3, %bb.4

    %3:sreg_64 = SI_IF undef %4:sreg_64, %bb.3, implicit-def dead $exec, implicit-def dead $scc, implicit $exec

  bb.4:
    successors: %bb.5

  bb.5:
    successors: %bb.6

    SI_END_CF %3:sreg_64, implicit-def dead $exec, implicit-def dead $scc, implicit $exec

  bb.6:
    SI_END_CF %2:sreg_64, implicit-def dead $exec, implicit-def dead $scc, implicit $exec
    S_ENDPGM 0

...

---
name: if_inside_loop
tracksRegLiveness: true
machineFunctionInfo:
  isEntryFunction: true
body:             |
  ; GCN-LABEL: name: if_inside_loop
  ; GCN: bb.0:
  ; GCN:   successors: %bb.6(0x80000000)
  ; GCN:   S_BRANCH %bb.6
  ; GCN: bb.1:
  ; GCN:   successors: %bb.3(0x40000000), %bb.2(0x40000000)
  ; GCN:   [[COPY:%[0-9]+]]:sreg_64 = COPY $exec, implicit-def $exec
  ; GCN:   [[S_AND_B64_:%[0-9]+]]:sreg_64 = S_AND_B64 [[COPY]], undef %1:sreg_64, implicit-def dead $scc
  ; GCN:   $exec = S_MOV_B64_term killed [[S_AND_B64_]]
  ; GCN:   S_CBRANCH_EXECZ %bb.3, implicit $exec
  ; GCN: bb.2:
  ; GCN:   successors: %bb.6(0x80000000)
  ; GCN:   S_BRANCH %bb.6
  ; GCN: bb.3:
  ; GCN:   successors: %bb.4(0x80000000)
  ; GCN:   $exec = S_OR_B64 $exec, [[COPY]], implicit-def $scc
  ; GCN: bb.4:
  ; GCN:   successors: %bb.5(0x80000000)
  ; GCN:   $exec = S_OR_B64 $exec, %2, implicit-def $scc
  ; GCN: bb.5:
  ; GCN:   successors: %bb.6(0x80000000)
  ; GCN: bb.6:
  ; GCN:   successors: %bb.4(0x40000000), %bb.0(0x40000000)
  ; GCN:   [[COPY1:%[0-9]+]]:sreg_64 = COPY $exec, implicit-def $exec
  ; GCN:   [[S_AND_B64_1:%[0-9]+]]:sreg_64 = S_AND_B64 [[COPY1]], undef %3:sreg_64, implicit-def dead $scc
  ; GCN:   [[S_XOR_B64_:%[0-9]+]]:sreg_64 = S_XOR_B64 [[S_AND_B64_1]], [[COPY1]], implicit-def dead $scc
  ; GCN:   $exec = S_MOV_B64_term killed [[S_AND_B64_1]]
  ; GCN:   S_CBRANCH_EXECZ %bb.4, implicit $exec
  ; GCN:   S_BRANCH %bb.0
  ; GCN:   S_ENDPGM 0
  bb.0:
    S_BRANCH %bb.6

  bb.1:
    %0:sreg_64 = SI_IF undef %1:sreg_64, %bb.3, implicit-def dead $exec, implicit-def dead $scc, implicit $exec

  bb.2:
    S_BRANCH %bb.6

  bb.3:
    SI_END_CF %0:sreg_64, implicit-def dead $exec, implicit-def dead $scc, implicit $exec

  bb.4:
    SI_END_CF %2:sreg_64, implicit-def dead $exec, implicit-def dead $scc, implicit $exec

  bb.5:

  bb.6:
    %2:sreg_64 = SI_IF undef %3:sreg_64, %bb.4, implicit-def dead $exec, implicit-def dead $scc, implicit $exec
    S_BRANCH %bb.0
    S_ENDPGM 0

...

---
# redundant MBB removal correctness test:
# we can keep bb.2 fallthrough to the  new succ because after bb.3 gets removed
# new succ (bb.4) becomes bb.2's layout successor
name: removed_succ_fallthrough_but_layout_successor
tracksRegLiveness: true
machineFunctionInfo:
  isEntryFunction: true
body:             |
  ; GCN-LABEL: name: removed_succ_fallthrough_but_layout_successor
  ; GCN: bb.0:
  ; GCN:   successors: %bb.1(0x40000000), %bb.4(0x40000000)
  ; GCN:   [[COPY:%[0-9]+]]:sreg_64 = COPY $exec, implicit-def $exec
  ; GCN:   [[S_AND_B64_:%[0-9]+]]:sreg_64 = S_AND_B64 [[COPY]], undef %1:sreg_64, implicit-def dead $scc
  ; GCN:   $exec = S_MOV_B64_term killed [[S_AND_B64_]]
  ; GCN:   S_CBRANCH_EXECZ %bb.4, implicit $exec
  ; GCN: bb.1:
  ; GCN:   successors: %bb.2(0x40000000), %bb.4(0x40000000)
  ; GCN:   [[COPY1:%[0-9]+]]:sreg_64 = COPY $exec, implicit-def $exec
  ; GCN:   [[S_AND_B64_1:%[0-9]+]]:sreg_64 = S_AND_B64 [[COPY1]], undef %3:sreg_64, implicit-def dead $scc
  ; GCN:   $exec = S_MOV_B64_term killed [[S_AND_B64_1]]
  ; GCN:   S_CBRANCH_EXECZ %bb.4, implicit $exec
  ; GCN: bb.2:
  ; GCN:   successors: %bb.4(0x80000000)
  ; GCN: bb.4:
  ; GCN:   successors: %bb.5(0x80000000)
  ; GCN:   $exec = S_OR_B64 $exec, [[COPY]], implicit-def $scc
  ; GCN: bb.5:
  ; GCN:   S_ENDPGM 0
  bb.0:
    successors: %bb.1, %bb.4

    %0:sreg_64 = SI_IF undef %1:sreg_64, %bb.4, implicit-def dead $exec, implicit-def dead $scc, implicit $exec

  bb.1:
    successors: %bb.2, %bb.3

    %2:sreg_64 = SI_IF undef %3:sreg_64, %bb.3, implicit-def dead $exec, implicit-def dead $scc, implicit $exec

  bb.2:

  bb.3:
    SI_END_CF %2:sreg_64, implicit-def dead $exec, implicit-def dead $scc, implicit $exec


  bb.4:
    SI_END_CF %0:sreg_64, implicit-def dead $exec, implicit-def dead $scc, implicit $exec

  bb.5:
    S_ENDPGM 0

...

---
# redundant MBB removal correctness test:
# If one of the remdundant block preds has a fallthrough path, but the only redundant block succ is not
# going to be a layout successor to that pred after redundant block removal, we should not rearrange
# blocks to keep pred's fallthrough path, if the succ has fallthrough path to one of it's succ too.

name: deleted_succ_fallthrough_not_layout_successor
tracksRegLiveness: true
machineFunctionInfo:
  isEntryFunction: true
body:             |
  ; GCN-LABEL: name: deleted_succ_fallthrough_not_layout_successor
  ; GCN: bb.0:
  ; GCN:   successors: %bb.1(0x40000000), %bb.4(0x40000000)
  ; GCN:   [[COPY:%[0-9]+]]:sreg_64 = COPY $exec, implicit-def $exec
  ; GCN:   [[S_AND_B64_:%[0-9]+]]:sreg_64 = S_AND_B64 [[COPY]], undef %1:sreg_64, implicit-def dead $scc
  ; GCN:   $exec = S_MOV_B64_term killed [[S_AND_B64_]]
  ; GCN:   S_CBRANCH_EXECZ %bb.4, implicit $exec
  ; GCN: bb.1:
  ; GCN:   successors: %bb.2(0x40000000), %bb.5(0x40000000)
  ; GCN:   [[COPY1:%[0-9]+]]:sreg_64 = COPY $exec, implicit-def $exec
  ; GCN:   [[S_AND_B64_1:%[0-9]+]]:sreg_64 = S_AND_B64 [[COPY1]], undef %3:sreg_64, implicit-def dead $scc
  ; GCN:   $exec = S_MOV_B64_term killed [[S_AND_B64_1]]
  ; GCN:   S_CBRANCH_EXECZ %bb.5, implicit $exec
  ; GCN: bb.2:
  ; GCN:   successors: %bb.5(0x80000000)
  ; GCN:   S_BRANCH %bb.5
  ; GCN: bb.4:
  ; GCN:   S_ENDPGM 0
  ; GCN: bb.5:
  ; GCN:   successors: %bb.6(0x80000000)
  ; GCN:   $exec = S_OR_B64 $exec, [[COPY]], implicit-def $scc
  ; GCN: bb.6:
  ; GCN:   successors: %bb.4(0x80000000)
  ; GCN:   S_BRANCH %bb.4
  bb.0:
    successors: %bb.1, %bb.4

    %0:sreg_64 = SI_IF undef %1:sreg_64, %bb.4, implicit-def dead $exec, implicit-def dead $scc, implicit $exec

  bb.1:
    successors: %bb.2, %bb.3

    %2:sreg_64 = SI_IF undef %3:sreg_64, %bb.3, implicit-def dead $exec, implicit-def dead $scc, implicit $exec

  bb.2:

  bb.3:
    SI_END_CF %2:sreg_64, implicit-def dead $exec, implicit-def dead $scc, implicit $exec
    S_BRANCH %bb.5

  bb.4:
    S_ENDPGM 0


  bb.5:
    SI_END_CF %0:sreg_64, implicit-def dead $exec, implicit-def dead $scc, implicit $exec

  bb.6:
    S_BRANCH %bb.4

...