| Message ID | 20100622150351.GA5565@kam.mff.cuni.cz |
|---|---|
| State | New |
| Headers | show |
2010/6/22 Jan Hubicka <hubicka@ucw.cz>: >> > + <li>Improved auto-detection of <code>const</code> and <code>pure</code> >> > + functions. Newly <code>noreturn</code> functions are auto-detected. >> > + <p><code>-fsuggest-attribute</code> flag is available to make compiler >> >> I think the option is <a >> href="http://gcc.gnu.org/onlinedocs/gcc/Warning-Options.html#Warning-Options"><code>-Wsuggest-attribute=[const|pure|nothrow]</code></a> >> >> BTW, the description in the manual does not mention Wsuggest-attribute=nothrow. > > It is because nothrow is not implemented yet. I plan to update patch for that. I confused nothrow with noreturn, that is, noreturn is not listed as an option: -Wsuggest-attribute=[const|pure] Warn for cases where adding an attribute may be beneficial. The attributes currently supported are listed below. -Wsuggest-attribute=pure -Wsuggest-attribute=const (although the description does mention it). > Here s updated patch. I am not sure about HTML way of making linebreak ;) A new line in the rendered text is <br> but that should not be needed. Yet, you should add real linebreaks to fit within 80 columns. Cheers, Manuel.
On Tue, 22 Jun 2010, Jan Hubicka wrote: > + <li>Interprocedural optimizations improvements</li> I think that would be "optimimization improvements"? > + <li>Interprocedural framework was re-tuned for link time > + optimization.</li> "The interprocedural..." > + functions. Newly; <code>noreturn</code> functions are auto-detected. "Newly, ...." > + <p><a href="http://gcc.gnu.org/onlinedocs/gcc/Warning-Options.html#Warning-Options"><code>-Wsuggest-attribute=[const|pure|noreturn]</code></a> "The <a href=.... > + flag is available to make compiler to inform users when adding > + attributes into headers might improve code generation.</p></li> "available that informs users" "into" -> "to" > + <li>Inlining heuristics were improved: > + <ul> > + <li>A number of problems with large compilation units was fixed.</li> How about "Scalability for large compilation units was improved significantly"? > + <li>Virtual methods are inlined caller is inlined > + and devirtualization is possible then.</li> Something is missing/incorrect here? > + <li>Datastructures used by dataflow framework in GCC were reorganized "by the dataflow" > + Compile time of GCC C compiler binary with link time optimization > + has reduced by over 10% (benchmarked on x86-64 target).</li> "The compile time of the GCC C compiler binary with link-time...went down by over 10%..." Thanks for taking the time to document this, Honza. Please go ahead and commit a patch looking at the suggestions above, and I will then have another look and make adjustments if I spot anything. Gerald
> On Tue, 22 Jun 2010, Jan Hubicka wrote: > > + <li>Interprocedural optimizations improvements</li> > > I think that would be "optimimization improvements"? > > > + <li>Interprocedural framework was re-tuned for link time > > + optimization.</li> > > "The interprocedural..." > > > + functions. Newly; <code>noreturn</code> functions are auto-detected. > > "Newly, ...." > > > + <p><a href="http://gcc.gnu.org/onlinedocs/gcc/Warning-Options.html#Warning-Options"><code>-Wsuggest-attribute=[const|pure|noreturn]</code></a> > > "The <a href=.... > > > + flag is available to make compiler to inform users when adding > > + attributes into headers might improve code generation.</p></li> > > "available that informs users" > "into" -> "to" > > > > + <li>Inlining heuristics were improved: > > + <ul> > > + <li>A number of problems with large compilation units was fixed.</li> > > How about "Scalability for large compilation units was improved > significantly"? > > > + <li>Virtual methods are inlined caller is inlined > > + and devirtualization is possible then.</li> > > Something is missing/incorrect here? Ah, should not write those things late in night :) It should be Virtual methods are inlined when caller is inlined and devirtualization is possible then. It is Martin's indirect inlining change. Honza
Index: changes.html =================================================================== RCS file: /cvs/gcc/wwwdocs/htdocs/gcc-4.6/changes.html,v retrieving revision 1.18 diff -u -r1.18 changes.html --- changes.html 13 Jun 2010 12:44:28 -0000 1.18 +++ changes.html 22 Jun 2010 15:01:28 -0000 @@ -43,6 +43,34 @@ with options that can affect standards compliance but result in better optimized code. For example <code>-Ofast</code> enables <code>-ffast-math</code>.</li> + <li>Interprocedural optimizations improvements</li> + <ul> + <li>Interprocedural framework was re-tuned for link time + optimization.</li> + <li>Improved auto-detection of <code>const</code> and <code>pure</code> + functions. Newly; <code>noreturn</code> functions are auto-detected. + <p><a href="http://gcc.gnu.org/onlinedocs/gcc/Warning-Options.html#Warning-Options"><code>-Wsuggest-attribute=[const|pure|noreturn]</code></a> + flag is available to make compiler to inform users when adding + attributes into headers might improve code generation.</p></li> + <li>Inlining heuristics were improved: + <ul> + <li>A number of problems with large compilation units was fixed.</li> + <li>Inlining of callbacks is now more aggressive.</li> + <li>Virtual methods are inlined caller is inlined + and devirtualization is possible then.</li> + </ul> + <li> + </ul> + </ul> + +<h2>Compile time and memory usage improvements</h2> + <ul> + <li>Datastructures used by dataflow framework in GCC were reorganized + for better memory usage and more cache locality. Compile + time is improved especially on units with large functions (possibly + resulting from a lot of inlining) not fitting in processor cache. + Compile time of GCC C compiler binary with link time optimization + has reduced by over 10% (benchmarked on x86-64 target).</li> </ul> <h2>New Languages and Language specific improvements</h2>