https://gcc.gnu.org/bugzilla/show_bug.cgi?id=84178
--- Comment #2 from Arseny Solokha <asolokha at gmx dot com> ---
Trivial change to the testcase also makes gcc-8 ICE in mark_block_for_update():
--- tt.c~ 2018-02-05 11:46:10.616358242 +0700
+++ tt.c 2018-02-05 11:46:14.640320524 +0700
@@ -7,7 +7,7 @@ r8 (long int mu, int *jr, int *fi, short
{
int tx;
- tx = !!h4 ? (zy / h4) : 1;
+ tx = !!h4 ? (zy + h4) : 1;
mu = tx;
*jr = (((unsigned char) mu > (254 >> dv)) ? 0 : (unsigned char) tx) +
*fi;
} while (*jr == 0);
% gcc-8.0.0-alpha20180204 -O3 -fno-tree-forwprop -c tt.c
during GIMPLE pass: ifcvt
tt.c: In function 'r8':
tt.c:4:1: internal compiler error: Segmentation fault
r8 (long int mu, int *jr, int *fi, short int dv)
^~
0xc97d0f crash_signal
/var/tmp/portage/sys-devel/gcc-8.0.0_alpha20180204/work/gcc-8-20180204/gcc/toplev.c:325
0xd1d788 mark_block_for_update
/var/tmp/portage/sys-devel/gcc-8.0.0_alpha20180204/work/gcc-8-20180204/gcc/tree-into-ssa.c:449
0xd27297 mark_use_interesting
/var/tmp/portage/sys-devel/gcc-8.0.0_alpha20180204/work/gcc-8-20180204/gcc/tree-into-ssa.c:2546
0xd27297 prepare_use_sites_for
/var/tmp/portage/sys-devel/gcc-8.0.0_alpha20180204/work/gcc-8-20180204/gcc/tree-into-ssa.c:2711
0xd27297 prepare_names_to_update
/var/tmp/portage/sys-devel/gcc-8.0.0_alpha20180204/work/gcc-8-20180204/gcc/tree-into-ssa.c:2779
0xd27297 update_ssa(unsigned int)
/var/tmp/portage/sys-devel/gcc-8.0.0_alpha20180204/work/gcc-8-20180204/gcc/tree-into-ssa.c:3345
0xd028aa version_loop_for_if_conversion
/var/tmp/portage/sys-devel/gcc-8.0.0_alpha20180204/work/gcc-8-20180204/gcc/tree-if-conv.c:2594
0xd0829a tree_if_conversion(loop*)
/var/tmp/portage/sys-devel/gcc-8.0.0_alpha20180204/work/gcc-8-20180204/gcc/tree-if-conv.c:2854
0xd0a335 execute
/var/tmp/portage/sys-devel/gcc-8.0.0_alpha20180204/work/gcc-8-20180204/gcc/tree-if-conv.c:2962
