llvm-project/llvm/test/CodeGen/Hexagon/livephysregs-add-pristines.mir

# RUN: llc -march=hexagon -run-pass if-converter -o - %s -verify-machineinstrs | FileCheck %s

# The register r23 is live on the path bb.0->bb.2->bb.3. Make sure we add
# an implicit use of r23 to the predicated redefinition:
# CHECK: $r23 = A2_tfrt killed $p0, killed $r1, implicit killed $r23

# LivePhysRegs::addPristines could accidentally remove a callee-saved
# register, if it determined that it wasn't pristine. Doing that caused
# r23 in this testcase to be dropped from the Redefs set, and subsequently
# the necessary implicit use was not added for it.

---
name: foo
tracksRegLiveness: true
fixedStack:
  - { id: 0, offset: 0, size: 4, alignment: 4, callee-saved-register: '$r23' }
body: |
  bb.0:
    successors: %bb.1, %bb.2
    liveins: $r0, $r1, $r23
      $p0 = C2_cmpgti killed $r0, 0
      J2_jumpf killed $p0, %bb.2, implicit-def $pc

  bb.1:
    successors: %bb.3
    liveins: $r1
      $r23 = A2_tfr killed $r1
      J2_jump %bb.3, implicit-def $pc

  bb.2:
    successors: %bb.3
    liveins: $r1, $r23
      $r0 = A2_tfr $r1

  bb.3:
    liveins: $r23
...