Date: Sat, 8 Apr 2000 14:18:47 -0700 (PDT) From: Kris Kennaway <kris@FreeBSD.org> To: "Alexey N. Dokuchaev" <danfe@inet.ssc.nsu.ru> Cc: freebsd-hackers@freebsd.org Subject: Re: What are the best gcc optimization options for Pentium 200 MMX Message-ID: <Pine.BSF.4.21.0004081416110.70551-100000@freefall.freebsd.org> In-Reply-To: <Pine.LNX.4.10.10004082114170.23805-100000@inet.ssc.nsu.ru>
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On Sat, 8 Apr 2000, Alexey N. Dokuchaev wrote:
> AFAIK, Linux Mandrake has it's kernel and userland highly optimized for
> Pentium architecture. However, they have additional gcc optimization
> flags turned on by default, including -O3 and -mfast_math.
Can you say "gimmick"? :-) gcc often produces demonstrably broken code for
optimisation levels higher than -O.
Probably the only useful and safe option apart from -O is the
-march=pentium/pentiumpro/pentiumii/etc option for using
processor-specific opcodes and instruction scheduling.
By all means, compile your own system the way you want, but be sure to
recompile with nothing but -O before submitting any bug reports.
Kris
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