[Bug middle-end/53852] -ftree-loop-linear: large compile time / memory usage

[rguenth at gcc dot gnu.org]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=53852

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

           What    |Removed                     |Added
----------------------------------------------------------------------------
           Keywords|                            |compile-time-hog,
                   |                            |memory-hog
             Status|UNCONFIRMED                 |NEW
   Last reconfirmed|                            |2012-07-04
                 CC|                            |matz at gcc dot gnu.org,
                   |                            |rguenth at gcc dot gnu.org
     Ever Confirmed|0                           |1

--- Comment #1 from Richard Guenther <rguenth at gcc dot gnu.org> 2012-07-04 11:54:42 UTC ---
From

#20 0x00000000012171c0 in compute_deps (scop=0x1f16e50, pbbs=0x1fa6d70, 
    must_raw=0x1f16e90, may_raw=0x1f16e98, must_raw_no_source=0x1f16ea0, 
    may_raw_no_source=0x1f16ea8, must_war=0x1f16eb0, may_war=0x1f16eb8, 
    must_war_no_source=0x1f16ec0, may_war_no_source=0x1f16ec8, 
    must_waw=0x1f16ed0, may_waw=0x1f16ed8, must_waw_no_source=0x1f16ee0, 
    may_waw_no_source=0x1f16ee8)
    at /space/rguenther/src/svn/trunk/gcc/graphite-dependences.c:471
471       res = isl_union_map_compute_flow (isl_union_map_copy (reads),

we do not finish without allocating much much memory.

from inside ISL it's compute_val_based_dependences that takes that much
memory and compile-time.