[Bug tree-optimization/71351] [7 Regression] ICE: Segmentation fault (graphite)

rguenth at gcc dot gnu.org gcc-bugzilla@gcc.gnu.org
Thu Feb 9 12:26:00 GMT 2017


https://gcc.gnu.org/bugzilla/show_bug.cgi?id=71351

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

           What    |Removed                     |Added
----------------------------------------------------------------------------
                 CC|                            |spop at gcc dot gnu.org

--- Comment #8 from Richard Biener <rguenth at gcc dot gnu.org> ---
Also ICEs with -fgraphite-identity.

The issue seems to be that ISL creates a new loop guard but the loop has a
loop-close PHI node and we fail to generate/know the value to use on the
edge that skips the loop.  The condition we try to insert is _19 > 0
(that's trivially true by means of a dominating condition).

Not sure how this is supposed to work for reductions when the orginal loops
guard is not in the SESE region.  That guard looks like

  _19 = *nc_18(D);
  if (_19 <= 0)
    ...

so the BB is rejected because _19 = *nc_18(D) isn't a valid stmt.  So for this
case it might help if we'd split that block...

Anyway, it looks like we have to fail code generation here somehow... (no good
idea how).


More information about the Gcc-bugs mailing list