https://gcc.gnu.org/bugzilla/show_bug.cgi?id=70989
--- Comment #1 from Oleg Endo <olegendo at gcc dot gnu.org> ---
Another case from bzlib.c:
.L820:
bt .L823
mov.l r0,@r7
.L823:
tst r11,r11
bt/s .L824 <<< convert to zero-displacement cbranch
mov #0,r1 <<< move common insn from successor bb to this bb
mov.l r1,@r11
.L824:
tst r12,r12
bt/s .L825
mov #0,r1 <<< likewise
mov.l r1,@r12
.L825:
result (1):
.L820:
bt .L823
mov.l r0,@r7
.L823:
tst r11,r11
mov #0,r1 <<< now r1 can be propagated into successor blocks
bt .L824
mov.l r1,@r11
.L824:
mov #0,r1
tst r12,r12
bt .L825
mov.l r1,@r12
.L825:
result (2):
.L820:
bt .L823
mov.l r0,@r7
.L823:
tst r11,r11
mov #0,r1
bt .L824
mov.l r1,@r11
.L824:
tst r12,r12
bt .L825
mov.l r1,@r12
.L825:
