# RUN: llc -march=hexagon -run-pass branch-folder %s -o - -verify-machineinstrs | FileCheck %s
# Branch folding will perform tail merging of bb.1 and bb.2, and bb.2 will
# become the common tail. The use of R0 in bb.2 is <undef> while the
# corresponding use in bb.1 is not. The common tail will have the <undef>
# flag removed, which will cause R0 to become a live-in to bb.2. The problem
# is that R0 is not live-out from all predecessors of bb.2, namely is not
# live-out from bb.0. To remedy that, the branch folder should add an
# IMPLICIT_DEF to that block.
# CHECK-LABEL: name: func0
# CHECK-LABEL: bb.0:
# CHECK: $r0 = IMPLICIT_DEF
# CHECK-LABEL: bb.1:
# CHECK-LABEL: bb.2:
# CHECK: liveins: $r0
# CHECK: PS_storerhabs 0, $r0
# CHECK: PS_jmpret
---
name: func0
tracksRegLiveness: true
body: |
bb.0:
liveins: $r31
successors: %bb.1, %bb.2
J2_jumpt undef $p0, %bb.2, implicit-def $pc
J2_jump %bb.1, implicit-def $pc
bb.1:
liveins: $r31
successors: %bb.3
$r0 = L2_loadruh_io undef $r1, 0
PS_storerhabs 0, killed $r0
J2_jump %bb.3, implicit-def $pc
bb.2:
liveins: $r31
successors: %bb.3
PS_storerhabs 0, undef $r0
J2_jump %bb.3, implicit-def $pc
bb.3:
liveins: $r31
PS_jmpret killed $r31, implicit-def $pc
...
---
# CHECK-LABEL: name: func1
# CHECK-LABEL: bb.1:
# CHECK: $r0 = IMPLICIT_DEF
# CHECK-LABEL: bb.2:
# CHECK-LABEL: bb.3:
# CHECK: liveins: $r0
# CHECK: PS_storerhabs 0, killed $r0
# CHECK: PS_jmpret
name: func1
tracksRegLiveness: true
body: |
bb.0:
liveins: $r31
successors: %bb.1, %bb.2
J2_jumpt undef $p0, %bb.2, implicit-def $pc
J2_jump %bb.1, implicit-def $pc
bb.1:
liveins: $r31
successors: %bb.3
$r1 = A2_tfrsi 1
PS_storerhabs 0, undef $r0
$r0 = A2_tfrsi 1
J2_jump %bb.3, implicit-def $pc
bb.2:
liveins: $r31
successors: %bb.3
$r0 = L2_loadruh_io undef $r1, 0
PS_storerhabs 0, killed $r0
$r0 = A2_tfrsi 1
J2_jump %bb.3, implicit-def $pc
bb.3:
liveins: $r31
PS_jmpret killed $r31, implicit undef $r0, implicit-def $pc
...
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