http://gcc.gnu.org/bugzilla/show_bug.cgi?id=59811
Richard Biener <rguenth at gcc dot gnu.org> changed:
What |Removed |Added
----------------------------------------------------------------------------
Status|UNCONFIRMED |NEW
Known to work| |4.7.3
Keywords| |compile-time-hog
Last reconfirmed| |2014-01-15
Component|fortran |rtl-optimization
Ever confirmed|0 |1
Summary|Huge increase in memory |[4.8/4.9 Regression] Huge
|usage and compile time with |increase in memory usage
|gfortran 4.8 |and compile time with
| |gfortran 4.8
Target Milestone|--- |4.8.3
Known to fail| |4.8.2, 4.9.0
--- Comment #1 from Richard Biener <rguenth at gcc dot gnu.org> ---
Confirmed. At -O2 I see for 4.8
alias stmt walking : 4.90 ( 8%) usr 0.02 ( 3%) sys 5.05 ( 8%) wall
0 kB ( 0%) ggc
tree copy propagation : 0.02 ( 0%) usr 0.00 ( 0%) sys 0.02 ( 0%) wall
513 kB ( 0%) ggc
combiner : 45.94 (71%) usr 0.57 (83%) sys 46.57 (71%) wall
1612812 kB (96%) ggc
integrated RA : 0.59 ( 1%) usr 0.01 ( 1%) sys 0.58 ( 1%) wall
12481 kB ( 1%) ggc
LRA hard reg assignment : 7.53 (12%) usr 0.03 ( 4%) sys 7.56 (11%) wall
0 kB ( 0%) ggc
TOTAL : 65.03 0.69 65.92
1681500 kB
and for 4.7
alias stmt walking : 2.77 (28%) usr 0.02 (17%) sys 2.80 (28%) wall
0 kB ( 0%) ggc
tree copy propagation : 1.64 (17%) usr 0.01 ( 8%) sys 1.67 (17%) wall
513 kB ( 1%) ggc
integrated RA : 0.66 ( 7%) usr 0.02 (17%) sys 0.68 ( 7%) wall
6295 kB (10%) ggc
reload : 0.45 ( 5%) usr 0.01 ( 8%) sys 0.46 ( 5%) wall
1593 kB ( 3%) ggc
reload CSE regs : 0.74 ( 7%) usr 0.00 ( 0%) sys 0.75 ( 7%) wall
1103 kB ( 2%) ggc
TOTAL : 9.87 0.12 10.01
61922 kB
the combiner slowdown and the LRA thing are worth investigating. I suppose
the generated code differs quite a bit ;) It's a very large function
with some very large basic-block(s). Current trunk behaves comparable
to GCC 4.8.
