Gentoo Package Management with Portage

Gentoo Package Management with Portage

Posted Jun 10, 2004 6:55 UTC (Thu) by piman (subscriber, #8957)
Parent article: Gentoo Package Management with Portage

It's disappointing to see -O3 mentioned without the caveat that much of the time, it can make code take longer by blowing icache, and register renaming makes debugging a pain.

It's true that much is said about CFLAGS; and the safest thing to do by far is to turn on -O2 and leave it at that. Knowing what the "correct" optimizations are for a piece of speed-critical code involves more work and knowledge about how machine code is generated than most users have, and arch-specific optimizations tend to trigger complex and subtle compiler bugs, that most users and developers are not prepared to debug.

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