1# RUN: llc -march=hexagon -run-pass branch-folder -run-pass if-converter -verify-machineinstrs %s -o - | FileCheck %s
2
3# The hoisting of common instructions from successors could cause registers
4# to no longer be live-in in the successor blocks. The liveness was updated
5# to include potential new live-in registres, but not to remove registers
6# that were no longer live-in.
7# This could cause if-converter to generate incorrect code.
8#
9# In this testcase, the "r1 = A2_sxth killed r0" was hoisted, and since r0
10# was killed, it was no longer live-in in either successor. The if-converter
11# then created code, where the first predicated instruction has incorrect
12# implicit use of r0:
13#
14# %bb.0:
15#     liveins: %r0
16#         %r1 = A2_sxth killed %r0               ; hoisted, kills r0
17#         A2_nop implicit-def %P0
18#         %r0 = C2_cmoveit %P0, 2, implicit %r0 ; predicated A2_tfrsi
19#         %r0 = C2_cmoveif killed %P0, 1, implicit %r0 ; predicated A2_tfrsi
20#         %r0 = A2_add killed %r0, killed %r1
21#         J2_jumpr %r31, implicit dead %PC
22#
23
24# CHECK: $r1 = A2_sxth killed $r0
25# CHECK: $r0 = C2_cmoveit $p0, 2
26# CHECK-NOT: implicit-def $r0
27# CHECK: $r0 = C2_cmoveif killed $p0, 1, implicit killed $r0
28
29---
30name: fred
31tracksRegLiveness: true
32
33body: |
34  bb.0:
35    liveins: $r0
36    successors: %bb.1, %bb.2
37
38    A2_nop implicit-def $p0
39    J2_jumpt killed $p0, %bb.2, implicit-def dead $pc
40
41  bb.1:
42    successors: %bb.3
43    liveins: $r0
44    $r1 = A2_sxth killed $r0
45    $r0 = A2_tfrsi 1
46    J2_jump %bb.3, implicit-def $pc
47
48  bb.2:
49    successors: %bb.3
50    liveins: $r0
51    $r1 = A2_sxth killed $r0
52    $r0 = A2_tfrsi 2
53
54  bb.3:
55    liveins: $r0, $r1
56    $r0 = A2_add killed $r0, killed $r1
57    J2_jumpr $r31, implicit-def dead $pc
58...
59
60