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e: GCC 3.3 compile speed regression - AN ANSWER
- From: Tim Josling <tej at melbpc dot org dot au>
- To: gcc at gcc dot gnu dot org, austern at apple dot com
- Date: Thu, 13 Feb 2003 19:52:21 +1100
- Subject: e: GCC 3.3 compile speed regression - AN ANSWER
- Organization: Melbourne PC User Group
- References: <1045083441.917.ezmlm@gcc.gnu.org>
> Wed, 12 Feb 2003 11:19:28 -0800
> From: Matt Austern <austern@apple.com>
> To: Joseph S. Myers" <jsm28@cam.ac.uk>
> CC: Linus Torvalds <torvalds@transmeta.com>, gcc@gcc.gnu.org
> On Tuesday, February 11, 2003, at 11:52 PM, Joseph S. Myers wrote:
> parser : 2.40 (42%) usr 0.27 (20%) sys 2.88 (40%) wall
> TOTAL : 5.69 1.36 7.12
>
> In this example the -fsyntax-only run happens to be slower. That's not
> always the case, but it illustrates my point: for this -O0 compilation,
> the
> time taken by the back end is smaller than the measurement error.
>
> --Matt
Matt,
Have you done this with the profiler? The 'parser' includes a lot of back end
code through function calls. A lot of suprising things happen. For example,
the output assembler file still gets opened!
'parser' should read 'parser/etc' IMHO.
However most of the optimisation is omitted with syntax-only.
Tim Josling