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* [Bug pending/23378] New: code quality regression for complicated loop
@ 2005-08-13 18:03 martin at mpa-garching dot mpg dot de
2005-08-13 18:05 ` [Bug pending/23378] " martin at mpa-garching dot mpg dot de
` (4 more replies)
0 siblings, 5 replies; 6+ messages in thread
From: martin at mpa-garching dot mpg dot de @ 2005-08-13 18:03 UTC (permalink / raw)
To: gcc-bugs
A code quality regression was introduced into CVS between the timestamps
"-D 20050729 22:00:00 UT" and "-D 20050729 23:00:00 UT". It appears that
it iss caused by Jan Hubicka's patch from
http://gcc.gnu.org/ml/gcc-patches/2005-07/msg02021.html
If the attached testcase is compiled with the newer compiler, the runtime
of the generated executable is more than 50 per cent higher:
old compiler:
~/tmp/tmp2>g++ -O3 -march=pentium4 -mfpmath=sse testcase.cc
~/tmp/tmp2>time ./a.out
14.250u 0.020s 0:14.27 100.0% 0+0k 0+0io 205pf+0w
new compiler:
~/tmp/tmp2>g++ -O3 -march=pentium4 -mfpmath=sse testcase.cc
~/tmp/tmp2>time ./a.out
22.430u 0.030s 0:22.46 100.0% 0+0k 0+0io 205pf+0w
Both compilers have the same "g++ -v" output:
~/tmp/tmp2>g++ -v
Using built-in specs.
Target: i686-pc-linux-gnu
Configured with: /scratch/gcc/configure --quiet
--prefix=/afs/mpa/data/martin/ugcc --enable-languages=c++
--enable-mapped-location --disable-checking
Thread model: posix
gcc version 4.1.0 20050729 (experimental)
The hot spot of the code is the strange "loop" in lines 134-139
of alm_map_tools_orig.cc.
--
Summary: code quality regression for complicated loop
Product: gcc
Version: 4.1.0
Status: UNCONFIRMED
Severity: normal
Priority: P2
Component: pending
AssignedTo: unassigned at gcc dot gnu dot org
ReportedBy: martin at mpa-garching dot mpg dot de
CC: gcc-bugs at gcc dot gnu dot org,martin at mpa-garching
dot mpg dot de
GCC build triplet: i686-pc-linux-gnu
GCC host triplet: i686-pc-linux-gnu
GCC target triplet: i686-pc-linux-gnu
http://gcc.gnu.org/bugzilla/show_bug.cgi?id=23378
^ permalink raw reply [flat|nested] 6+ messages in thread
* [Bug pending/23378] code quality regression for complicated loop
2005-08-13 18:03 [Bug pending/23378] New: code quality regression for complicated loop martin at mpa-garching dot mpg dot de
@ 2005-08-13 18:05 ` martin at mpa-garching dot mpg dot de
2005-08-13 18:06 ` [Bug target/23378] [4.1 Regression] " pinskia at gcc dot gnu dot org
` (3 subsequent siblings)
4 siblings, 0 replies; 6+ messages in thread
From: martin at mpa-garching dot mpg dot de @ 2005-08-13 18:05 UTC (permalink / raw)
To: gcc-bugs
------- Additional Comments From martin at mpa-garching dot mpg dot de 2005-08-13 18:05 -------
Created an attachment (id=9494)
--> (http://gcc.gnu.org/bugzilla/attachment.cgi?id=9494&action=view)
A testcase for the problem
--
http://gcc.gnu.org/bugzilla/show_bug.cgi?id=23378
^ permalink raw reply [flat|nested] 6+ messages in thread
* [Bug target/23378] [4.1 Regression] code quality regression for complicated loop
2005-08-13 18:03 [Bug pending/23378] New: code quality regression for complicated loop martin at mpa-garching dot mpg dot de
2005-08-13 18:05 ` [Bug pending/23378] " martin at mpa-garching dot mpg dot de
@ 2005-08-13 18:06 ` pinskia at gcc dot gnu dot org
2005-08-14 13:57 ` steven at gcc dot gnu dot org
` (2 subsequent siblings)
4 siblings, 0 replies; 6+ messages in thread
From: pinskia at gcc dot gnu dot org @ 2005-08-13 18:06 UTC (permalink / raw)
To: gcc-bugs
--
What |Removed |Added
----------------------------------------------------------------------------
CC| |hubicka at gcc dot gnu dot
| |org
Component|pending |target
Summary|code quality regression for |[4.1 Regression] code
|complicated loop |quality regression for
| |complicated loop
Target Milestone|--- |4.1.0
http://gcc.gnu.org/bugzilla/show_bug.cgi?id=23378
^ permalink raw reply [flat|nested] 6+ messages in thread
* [Bug target/23378] [4.1 Regression] code quality regression for complicated loop
2005-08-13 18:03 [Bug pending/23378] New: code quality regression for complicated loop martin at mpa-garching dot mpg dot de
2005-08-13 18:05 ` [Bug pending/23378] " martin at mpa-garching dot mpg dot de
2005-08-13 18:06 ` [Bug target/23378] [4.1 Regression] " pinskia at gcc dot gnu dot org
@ 2005-08-14 13:57 ` steven at gcc dot gnu dot org
2005-08-14 14:07 ` pinskia at gcc dot gnu dot org
2005-08-16 8:38 ` martin at mpa-garching dot mpg dot de
4 siblings, 0 replies; 6+ messages in thread
From: steven at gcc dot gnu dot org @ 2005-08-14 13:57 UTC (permalink / raw)
To: gcc-bugs
------- Additional Comments From steven at gcc dot gnu dot org 2005-08-14 13:57 -------
Ouch. This badly needs reducing...
--
http://gcc.gnu.org/bugzilla/show_bug.cgi?id=23378
^ permalink raw reply [flat|nested] 6+ messages in thread
* [Bug target/23378] [4.1 Regression] code quality regression for complicated loop
2005-08-13 18:03 [Bug pending/23378] New: code quality regression for complicated loop martin at mpa-garching dot mpg dot de
` (2 preceding siblings ...)
2005-08-14 13:57 ` steven at gcc dot gnu dot org
@ 2005-08-14 14:07 ` pinskia at gcc dot gnu dot org
2005-08-16 8:38 ` martin at mpa-garching dot mpg dot de
4 siblings, 0 replies; 6+ messages in thread
From: pinskia at gcc dot gnu dot org @ 2005-08-14 14:07 UTC (permalink / raw)
To: gcc-bugs
------- Additional Comments From pinskia at gcc dot gnu dot org 2005-08-14 14:06 -------
I think this is related to PR 23302 and PR 23303 since those look like they were caused by the same
patch.
--
What |Removed |Added
----------------------------------------------------------------------------
BugsThisDependsOn| |23302, 23303
http://gcc.gnu.org/bugzilla/show_bug.cgi?id=23378
^ permalink raw reply [flat|nested] 6+ messages in thread
* [Bug target/23378] [4.1 Regression] code quality regression for complicated loop
2005-08-13 18:03 [Bug pending/23378] New: code quality regression for complicated loop martin at mpa-garching dot mpg dot de
` (3 preceding siblings ...)
2005-08-14 14:07 ` pinskia at gcc dot gnu dot org
@ 2005-08-16 8:38 ` martin at mpa-garching dot mpg dot de
4 siblings, 0 replies; 6+ messages in thread
From: martin at mpa-garching dot mpg dot de @ 2005-08-16 8:38 UTC (permalink / raw)
To: gcc-bugs
------- Additional Comments From martin at mpa-garching dot mpg dot de 2005-08-16 08:33 -------
(In reply to comment #2)
> Ouch. This badly needs reducing...
Absolutely. But since Andrew pointed out that it is probably related to PR 23302
and PR 23303 (which have nice testcases), I suggest I wait until these are fixed.
If, after that, the performance regression persists, I'll try to reduce the
testcase. Is that OK?
--
http://gcc.gnu.org/bugzilla/show_bug.cgi?id=23378
^ permalink raw reply [flat|nested] 6+ messages in thread
end of thread, other threads:[~2005-08-16 8:33 UTC | newest]
Thread overview: 6+ messages (download: mbox.gz / follow: Atom feed)
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2005-08-13 18:03 [Bug pending/23378] New: code quality regression for complicated loop martin at mpa-garching dot mpg dot de
2005-08-13 18:05 ` [Bug pending/23378] " martin at mpa-garching dot mpg dot de
2005-08-13 18:06 ` [Bug target/23378] [4.1 Regression] " pinskia at gcc dot gnu dot org
2005-08-14 13:57 ` steven at gcc dot gnu dot org
2005-08-14 14:07 ` pinskia at gcc dot gnu dot org
2005-08-16 8:38 ` martin at mpa-garching dot mpg dot de
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