[Bug tree-optimization/81181] New: [7/8 Regression] ICE in compute_antic, at tree-ssa-pre.c:2410

[asolokha at gmx dot com]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=81181

            Bug ID: 81181
           Summary: [7/8 Regression] ICE in compute_antic, at
                    tree-ssa-pre.c:2410
           Product: gcc
           Version: 8.0
            Status: UNCONFIRMED
          Keywords: compile-time-hog, ice-on-valid-code
          Severity: normal
          Priority: P3
         Component: tree-optimization
          Assignee: unassigned at gcc dot gnu.org
          Reporter: asolokha at gmx dot com
  Target Milestone: ---

gcc-8.0.0-alpha20170618 snapshot ICEs, while gcc 7.1 takes inordinate time when
compiling the following snippet w/ -O2:

unsigned int lh;

void
ny (int t3, int ys, int rt, int p8)
{
  if (lh != 0)
    {
      if (0)
        {
 oo:
          do
            {
              rt = (p8 != 0) ? t3 : 0;
              rt = (rt != 0 || lh != (unsigned int)ys);
              rt += lh + ys;
            }
          while (t3 <= 0);

          lh = ys;
          ys = rt;
        }

      if (lh != 0)
        p8 = lh;
    }

  goto oo;
}

% gcc-8.0.0-alpha20170618 -O2 -c cv9l98qh.c                         
during GIMPLE pass: pre
cv9l98qh.c: In function 'ny':
cv9l98qh.c:4:1: internal compiler error: in compute_antic, at
tree-ssa-pre.c:2410
 ny (int t3, int ys, int rt, int p8)
 ^~