[Bug middle-end/39326] Segmentation fault with -O1, out of memory with -O2

rguenth at gcc dot gnu.org gcc-bugzilla@gcc.gnu.org
Wed Mar 6 11:38:00 GMT 2013


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=39326

--- Comment #22 from Richard Biener <rguenth at gcc dot gnu.org> 2013-03-06 11:38:07 UTC ---
4.7.2  -O0  25s  2189981kB

 integrated RA           :   8.96 (35%) usr   0.89 (28%) sys   9.89 (34%) wall 
206439 kB (16%) ggc
 reload                  :   2.98 (12%) usr   0.07 ( 2%) sys   3.05 (11%) wall 
 43197 kB ( 3%) ggc

4.8.0  -O0  29s  2111318kB

 integrated RA           :   8.88 (31%) usr   0.41 (13%) sys   9.32 (29%) wall 
206439 kB (18%) ggc
 LRA non-specific        :   5.50 (19%) usr   0.08 ( 3%) sys   5.59 (17%) wall 
  4600 kB ( 0%) ggc

4.8.0  -O2  (terminated after 9 minutes waiting, LIM being the offender, I
suspect domwalk ...)  >2.5GB

applying domwalk fix ...

4.8.0  -O1  still awfully slow

the smaller testcase is also tested on http://gcc.opensuse.org/c++bench/random/
but it runs OOM at -O1 and -O2 there (there is a virtual ulimit of 1GB due
to lack of resources on the machine), but -O3 surprisingly works so you
can see a recent time-report there (also for -O0).

At -O3 you can see there (everything > 10%):

 tree loop invariant motion:  53.83 (13%) usr
 PRE                     : 116.26 (29%) usr 
 LRA hard reg assignment :  73.68 (18%) usr
 load CSE after reload   :  38.67 (10%) usr

ISTR the testcases are not exactly exposing the same issues.



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