llvm/test/CodeGen/AMDGPU/phi-elimination-split-critical-edge-undef-phi-source.mir

# RUN: llc -mtriple=amdgpu9.00 -passes='require<live-intervals>,phi-node-elimination,print<live-intervals>' -filetype=null %s 2>&1 | FileCheck %s

# %0 is only an undef PHI operand on the critical edge from %bb.1 to
# %bb.2, so splitting the edge must not leave %0 live through the new
# block.

# CHECK: ********** INTERVALS **********
# CHECK-NEXT: %0 [16r,[[SPLIT:[0-9]+]]B:0)
# CHECK: [[SPLIT]]B{{[[:space:]]+}}bb.5:

---
name: split_critical_edge_undef_phi_source
tracksRegLiveness: true
body: |
  bb.0:
    %0:vgpr_32 = V_MOV_B32_e32 0, implicit $exec
    %1:vgpr_32 = V_MOV_B32_e32 1, implicit $exec
    $scc = IMPLICIT_DEF
    S_CBRANCH_SCC1 %bb.1, implicit $scc
    S_BRANCH %bb.4

  bb.1:
    $scc = IMPLICIT_DEF
    S_CBRANCH_SCC1 %bb.3, implicit $scc
    S_BRANCH %bb.2

  bb.2:
    %2:vgpr_32 = PHI undef %0, %bb.1, %1, %bb.4
    S_ENDPGM 0, implicit %2

  bb.3:
    S_ENDPGM 0, implicit %0

  bb.4:
    S_BRANCH %bb.2
...