http://gcc.gnu.org/bugzilla/show_bug.cgi?id=54888
--- Comment #4 from Richard Biener <rguenth at gcc dot gnu.org> 2012-10-22 12:56:23 UTC --- (In reply to comment #3) > (In reply to comment #2) > > > And I actually don't understand teh issue: Optimizing for size does not > > require > > to produce slow code. The code may run fast. > > -O3 is supposed to produce the fastest possible code, but it doesn't. -Os is > faster. At the very least the two should be equal. Supposed to? Where in the documentation is that specified? I remember a sentence that -O3 enables optimization that might not always be profitable (but that sentence seems to be gone from latest docs). > In other words -O3 is broken. It's behavior is certainly undesirable, but broken? For certain targets -Os might be a win because that's what it is tuned for or icache behavior is simply more important than anything else.
