[Bug rtl-optimization/83913] New: [8 Regression] Compile time and memory hog w/ selective scheduling

[asolokha at gmx dot com]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=83913

            Bug ID: 83913
           Summary: [8 Regression] Compile time and memory hog w/
                    selective scheduling
           Product: gcc
           Version: 8.0
            Status: UNCONFIRMED
          Keywords: compile-time-hog, memory-hog
          Severity: normal
          Priority: P3
         Component: rtl-optimization
          Assignee: unassigned at gcc dot gnu.org
          Reporter: asolokha at gmx dot com
  Target Milestone: ---

gcc-8.0.0-alpha20180114 snapshot (r256677) takes indefinite time and consumes
large amount of memory compiling the following snippet w/ -O1 (-O2, -O3)
-funroll-all-loops -fselective-scheduling -fsel-sched-pipelining
-fschedule-insns -fno-dce -fno-forward-propagate -fno-rerun-cse-after-loop
-fno-web:

int jo, z4;

int
be (long unsigned int l7, int nt)
{
  int en;

  jo = l7;
  for (en = 0; en < 24; ++en)
    {
      jo = (jo / z4) * (!!jo >= ((!!nt) & 2));
      if (jo == 0)
        nt = 0;
      else
        {
          nt = z4;
          ++z4;
          nt = (long unsigned int) nt == (l7 + 1);
        }
    }

  return nt;
}

% timeout 5 gcc-8.0.0-alpha20180114 -O1 -funroll-all-loops
-fselective-scheduling -fsel-sched-pipelining -fschedule-insns -fno-dce
-fno-forward-propagate -fno-rerun-cse-after-loop -fno-web -c e6xgtk0x.c
zsh: exit 124   timeout 5 gcc-8.0.0-alpha20180114 -O1 -funroll-all-loops  
-fschedule-insns