[Bug rtl-optimization/85673] New: ICE in create_pre_exit, at mode-switching.c:451

[asolokha at gmx dot com]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=85673

            Bug ID: 85673
           Summary: ICE in create_pre_exit, at mode-switching.c:451
           Product: gcc
           Version: unknown
            Status: UNCONFIRMED
          Keywords: ice-checking, ice-on-invalid-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-unknown-linux-gnu

gcc-9.0.0-alpha20180429 snapshot (r259749), 8.1, 7.3, 6.3 all ICE when
compiling the following snippet w/ -mavx -O2 -fgcse-sm -fschedule-insns
-fselective-scheduling -fno-dce -fno-forward-propagate
-fno-rerun-cse-after-loop -fno-tree-dse -fno-tree-ter --param
selsched-max-lookahead=34:

int fn, l0, mo;

int
kg ();

int
pm (int *i2, int a8)
{
  int v8;

  a8 += kg ();
  v8 = a8 < fn;
  v8 = mo < v8;
  v8 = v8 < i2;
  v8 = mo < v8;
  mo += v8;
  a8 += l0;
  l0 += a8;

  for (fn = 0; fn < 1; ++fn)
    {
    }

  for (mo = 0; mo < 1; ++mo)
   {
   }

  return i2;
}

% x86_64-unknown-linux-gnu-gcc-9.0.0-alpha20180429 -mavx -O2 -fgcse-sm
-fschedule-insns -fselective-scheduling -fno-dce -fno-forward-propagate
-fno-rerun-cse-after-loop -fno-tree-dse -fno-tree-ter --param
selsched-max-lookahead=34 -w -c cyrbs0xx.c
during RTL pass: vzeroupper
cyrbs0xx.c: In function 'pm':
cyrbs0xx.c:29:1: internal compiler error: in create_pre_exit, at
mode-switching.c:451
 }
 ^
0x7372b7 create_pre_exit
       
/var/tmp/portage/sys-devel/gcc-9.0.0_alpha20180429/work/gcc-9-20180429/gcc/mode-switching.c:438
0x7372b7 optimize_mode_switching
       
/var/tmp/portage/sys-devel/gcc-9.0.0_alpha20180429/work/gcc-9-20180429/gcc/mode-switching.c:534
0x7372b7 execute
       
/var/tmp/portage/sys-devel/gcc-9.0.0_alpha20180429/work/gcc-9-20180429/gcc/mode-switching.c:892
0xfbc275 rest_of_handle_insert_vzeroupper
       
/var/tmp/portage/sys-devel/gcc-9.0.0_alpha20180429/work/gcc-9-20180429/gcc/config/i386/i386.c:898
0xfbc275 execute
       
/var/tmp/portage/sys-devel/gcc-9.0.0_alpha20180429/work/gcc-9-20180429/gcc/config/i386/i386.c:2518