test/CodeGen/Hexagon/branch-folder-hoist-kills.mir

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

# The hoisting of common instructions from successors could cause registers
# to no longer be live-in in the successor blocks. The liveness was updated
# to include potential new live-in registres, but not to remove registers
# that were no longer live-in.
# This could cause if-converter to generate incorrect code.
#
# In this testcase, the "r1 = A2_sxth r0<kill>" was hoisted, and since r0
# was killed, it was no longer live-in in either successor. The if-converter
# then created code, where the first predicated instruction has incorrect
# implicit use of r0:
#
# BB#0:
#     Live Ins: %R0
#         %R1<def> = A2_sxth %R0<kill>               ; hoisted, kills r0
#         A2_nop %P0<imp-def>
#         %R0<def> = C2_cmoveit %P0, 2, %R0<imp-use> ; predicated A2_tfrsi
#         %R0<def> = C2_cmoveif killed %P0, 1, %R0<imp-use> ; predicated A2_tfrsi
#         %R0<def> = A2_add %R0<kill>, %R1<kill>
#         J2_jumpr %R31, %PC<imp-def,dead>
#

# CHECK: %r1 = A2_sxth killed %r0
# CHECK: %r0 = C2_cmoveit %p0, 2
# CHECK-NOT: implicit-def %r0
# CHECK: %r0 = C2_cmoveif killed %p0, 1, implicit killed %r0

---
name: fred
tracksRegLiveness: true

body: |
  bb.0:
    liveins: %r0
    successors: %bb.1, %bb.2

    A2_nop implicit-def %p0
    J2_jumpt killed %p0, %bb.2, implicit-def dead %pc

  bb.1:
    successors: %bb.3
    liveins: %r0
    %r1 = A2_sxth killed %r0
    %r0 = A2_tfrsi 1
    J2_jump %bb.3, implicit-def %pc

  bb.2:
    successors: %bb.3
    liveins: %r0
    %r1 = A2_sxth killed %r0
    %r0 = A2_tfrsi 2

  bb.3:
    liveins: %r0, %r1
    %r0 = A2_add killed %r0, killed %r1
    J2_jumpr %r31, implicit-def dead %pc
...