[Bug tree-optimization/84650] [8 Regression] [graphite] ICE: Segmentation fault (in create_new_iv)

[rguenth at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=84650

Richard Biener <rguenth at gcc dot gnu.org> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
             Status|UNCONFIRMED                 |NEW
   Last reconfirmed|                            |2018-03-01
                 CC|                            |amker.cheng at gmail dot com,
                   |                            |rguenth at gcc dot gnu.org
   Target Milestone|---                         |8.0
     Ever confirmed|0                           |1

--- Comment #1 from Richard Biener <rguenth at gcc dot gnu.org> ---
Confirmed.

Program received signal SIGSEGV, Segmentation fault.
0x00000000011c1ebe in create_new_iv (data=0x7fffffffd870, cand=0x2cd98f0)
    at /space/rguenther/src/svn/early-lto-debug/gcc/tree-ssa-loop-ivopts.c:6793
6793          group = data->vgroups[use->group_id];
Missing separate debuginfos, use: zypper install
libgmp10-debuginfo-5.1.3-5.46.x86_64 libisl15-debuginfo-0.18-31.1.x86_64
libmpc3-debuginfo-1.0.2-4.55.x86_64 libmpfr4-debuginfo-3.1.2-11.53.x86_64
(gdb) p use
$1 = (iv_use *) 0x0


The reason is _possibly_ IL that isn't fully constant propagated, but that
can of course happen and we shouldn't rely on that.  Bin, can you have a
quick look?

  <bb 2> [local count: 14598063]:
  _4 = 1;
  _5 = (unsigned int) _4;
  _15 = 1 - _5;

  <bb 3> [local count: 118111601]:
  # eu_19 = PHI <0(2), eu_13(7)>
  eu_13 = _15 + eu_19;
  if (eu_13 <= 1)
    goto <bb 7>; [87.64%]
  else
    goto <bb 6>; [12.36%]

  <bb 7> [local count: 103513538]:
  goto <bb 3>; [100.00%]