[Bug rtl-optimization/85423] New: [8 Regression] ICE in code_motion_process_successors, at sel-sched.c:6403

[asolokha at gmx dot com]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=85423

            Bug ID: 85423
           Summary: [8 Regression] ICE in code_motion_process_successors,
                    at sel-sched.c:6403
           Product: gcc
           Version: 8.0
            Status: UNCONFIRMED
          Keywords: ice-on-valid-code
          Severity: normal
          Priority: P3
         Component: rtl-optimization
          Assignee: unassigned at gcc dot gnu.org
          Reporter: asolokha at gmx dot com
  Target Milestone: ---
            Target: x86_64-pc-linux-gnu

gcc-8.0.0-alpha20180415 snapshot (r259389) ICEs when compiling the following
snippet w/ -march=nano -O2 (-O3, -Ofast) -fselective-scheduling2
-fvar-tracking-assignments -fno-guess-branch-probability -fno-peephole2
-fno-ssa-phiopt -fno-tree-pre --param max-jump-thread-duplication-stmts=8:

int vn, xm;

void
i1 (int);

void
mb (int *ap, int ev)
{
  while (vn < 1)
    {
      i1 (vn);

      ev += *ap && ++vn;

      while (xm < 1)
        ++xm;

      if (*ap == 0)
        *ap = ev;

      ++vn;
    }
}

% x86_64-unknown-linux-gnu-gcc-8.0.0-alpha20180415 -march=nano -O2
-fselective-scheduling2 -fvar-tracking-assignments
-fno-guess-branch-probability -fno-peephole2 -fno-ssa-phiopt -fno-tree-pre
--param max-jump-thread-duplication-stmts=8 -w -c l7diilgr.c
during RTL pass: sched2
l7diilgr.c: In function 'mb':
l7diilgr.c:23:1: internal compiler error: in code_motion_process_successors, at
sel-sched.c:6403
 }
 ^
0xc6c314 code_motion_process_successors
       
/var/tmp/portage/sys-devel/gcc-8.0.0_alpha20180415/work/gcc-8-20180415/gcc/sel-sched.c:6400
0xc6c314 code_motion_path_driver
       
/var/tmp/portage/sys-devel/gcc-8.0.0_alpha20180415/work/gcc-8-20180415/gcc/sel-sched.c:6622
0xc6be6e code_motion_process_successors
       
/var/tmp/portage/sys-devel/gcc-8.0.0_alpha20180415/work/gcc-8-20180415/gcc/sel-sched.c:6356
0xc6be6e code_motion_path_driver
       
/var/tmp/portage/sys-devel/gcc-8.0.0_alpha20180415/work/gcc-8-20180415/gcc/sel-sched.c:6622
0xc6be6e code_motion_process_successors
       
/var/tmp/portage/sys-devel/gcc-8.0.0_alpha20180415/work/gcc-8-20180415/gcc/sel-sched.c:6356
0xc6be6e code_motion_path_driver
       
/var/tmp/portage/sys-devel/gcc-8.0.0_alpha20180415/work/gcc-8-20180415/gcc/sel-sched.c:6622
0xc6c512 move_op
       
/var/tmp/portage/sys-devel/gcc-8.0.0_alpha20180415/work/gcc-8-20180415/gcc/sel-sched.c:6714
0xc6c512 move_exprs_to_boundary
       
/var/tmp/portage/sys-devel/gcc-8.0.0_alpha20180415/work/gcc-8-20180415/gcc/sel-sched.c:5237
0xc6c512 schedule_expr_on_boundary
       
/var/tmp/portage/sys-devel/gcc-8.0.0_alpha20180415/work/gcc-8-20180415/gcc/sel-sched.c:5450
0xc705ac fill_insns
       
/var/tmp/portage/sys-devel/gcc-8.0.0_alpha20180415/work/gcc-8-20180415/gcc/sel-sched.c:5592
0xc705ac schedule_on_fences
       
/var/tmp/portage/sys-devel/gcc-8.0.0_alpha20180415/work/gcc-8-20180415/gcc/sel-sched.c:7366
0xc705ac sel_sched_region_2
       
/var/tmp/portage/sys-devel/gcc-8.0.0_alpha20180415/work/gcc-8-20180415/gcc/sel-sched.c:7504
0xc71d28 sel_sched_region_1
       
/var/tmp/portage/sys-devel/gcc-8.0.0_alpha20180415/work/gcc-8-20180415/gcc/sel-sched.c:7546
0xc725ae sel_sched_region(int)
       
/var/tmp/portage/sys-devel/gcc-8.0.0_alpha20180415/work/gcc-8-20180415/gcc/sel-sched.c:7647
0xc734c1 run_selective_scheduling()
       
/var/tmp/portage/sys-devel/gcc-8.0.0_alpha20180415/work/gcc-8-20180415/gcc/sel-sched.c:7733
0xc52d45 rest_of_handle_sched2
       
/var/tmp/portage/sys-devel/gcc-8.0.0_alpha20180415/work/gcc-8-20180415/gcc/sched-rgn.c:3732
0xc52d45 execute
       
/var/tmp/portage/sys-devel/gcc-8.0.0_alpha20180415/work/gcc-8-20180415/gcc/sched-rgn.c:3876