# NOTE: Assertions have been autogenerated by utils/update_mir_test_checks.py
# RUN: llc -march=amdgcn -mcpu=gfx803 -run-pass simple-register-coalescing -verify-machineinstrs -o - %s | FileCheck %s

# Register coalescer is going to eliminate %2:sgpr_32 = COPY %1.sub0 from bb.1
# by joining %2 and %1.sub0 into %0.sub0 register. Check that when this happen
# the implicit intialization of %0.sub0 in the bb.2 have undef flag
# for the MIR to be valid.

---
name: coalescing_makes_lane_undefined
tracksRegLiveness: true
body:             |
  ; CHECK-LABEL: name: coalescing_makes_lane_undefined
  ; CHECK: bb.0:
  ; CHECK:   successors: %bb.1(0x40000000), %bb.2(0x40000000)
  ; CHECK:   S_CBRANCH_SCC0 %bb.2, implicit undef $scc
  ; CHECK: bb.1:
  ; CHECK:   successors: %bb.3(0x80000000)
  ; CHECK:   undef %0.sub0:sgpr_64 = S_MOV_B32 1
  ; CHECK:   %0.sub1:sgpr_64 = S_MOV_B32 2
  ; CHECK:   S_BRANCH %bb.3
  ; CHECK: bb.2:
  ; CHECK:   successors: %bb.3(0x80000000)
  ; CHECK:   undef %0.sub0:sgpr_64 = IMPLICIT_DEF
  ; CHECK: bb.3:
  ; CHECK:   S_NOP 0, implicit %0.sub0
  ; CHECK:   S_NOP 0, implicit %0
  bb.0:
    successors: %bb.1, %bb.2
    S_CBRANCH_SCC0 %bb.2, implicit undef $scc

  bb.1:
    successors: %bb.3
    undef %1.sub0:sgpr_64 = S_MOV_B32 1
    %1.sub1:sgpr_64 = S_MOV_B32 2
    %2:sgpr_32 = COPY %1.sub0 ; copy to be joined
    S_BRANCH %bb.3

  bb.2:
    successors: %bb.3
    %2:sgpr_32 = IMPLICIT_DEF
    undef %1.sub0:sgpr_64 = IMPLICIT_DEF
    %1.sub1:sgpr_64 = IMPLICIT_DEF

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

...