# RUN: llc -march=x86-64 %s -o - -run-pass=processimpdefs -run-pass=unreachable-mbb-elimination | FileCheck %s
---
name:            f
tracksRegLiveness: true
registers:
  - { id: 0, class: gr32, preferred-register: '' }
  - { id: 1, class: gr32, preferred-register: '' }
  - { id: 2, class: gr32, preferred-register: '' }
body:             |
  bb.0:
    %0 = IMPLICIT_DEF
    JMP_1 %bb.1

  bb.1:
    %1 = PHI %0, %bb.0, %2, %bb.2
    %2 = ADD32ri8 killed %1, 1, implicit-def %eflags
    JMP_1 %bb.3

  bb.2:
    JMP_1 %bb.1

  bb.3:
...

# bb2 above is dead and should be removed and the PHI should be replaced with a
# COPY from an undef value since the bb0 value in the PHI is undef.

# CHECK:  bb.0:
# CHECK:    successors: %bb.1
# CHECK:    JMP_1 %bb.1

# CHECK:  bb.1:
# CHECK:    successors: %bb.2
# CHECK:    [[TMP1:%[0-9]+]]:gr32 = COPY undef %{{[0-9]+}}
# CHECK:    %{{[0-9]+}}:gr32 = ADD32ri8 killed [[TMP1]], 1
# CHECK:    JMP_1 %bb.2

# CHECK:  bb.2: