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Re: 100x -O0 Compile Time Regression {3.2,3.3} -> {3.4,3.5}
- From: Mike Stump <mrs at apple dot com>
- To: John Vickers <John at xza5 dot com>
- Cc: gcc at gcc dot gnu dot org
- Date: Thu, 12 Feb 2004 16:27:30 -0800
- Subject: Re: 100x -O0 Compile Time Regression {3.2,3.3} -> {3.4,3.5}
On Thursday, February 12, 2004, at 01:50 PM, John Vickers wrote:
We've got some generated C++ which compiles in about 10s (on a P4
2800) at -O0 with gcc-3.2 or 3.3.2, but takes about 1000s with 3.4.0
or 3.5.0.
:-(
Any suggestions as to where to start digging ? I can supply
preprocessed source to anyone interested.
Well, if you want to help track it down, you can binary search
compilers using the reghunt script from the web site. Once you narrow
it down to the patch(es) that cause the problems, we can ask that
person to look into it.
What the script essentially does is akin to cvs update -D '64 days ago'
. && make && test, and then loop, adding or subtracting 32, then 16,
then 8, then 4, then 2, then 1, and presto, the patch that caused it.
If you don't mind filing a bug report, please do, attach the file to
the bug report. Let me know which one it is, and I will help ensure
that the problem is fixed.
Thanks for reporting this.