Re: gcc -Os optimisation broken (RELENG_4)

[Jeffrey J. Mountin]

At 01:42 PM 3/16/00 +0100, Christian Weisgerber wrote:
>David O'Brien <[EMAIL PROTECTED]> wrote:
>
> > What???  'pentiumpro' code isn't going to be very optimized for a Pentium
> > (if it even runs at all).
>
>According to the gcc(1) man page, -mpentiumpro is synonymous to
>-mcpu=pentiumpro, which only affects instruction scheduling but
>not the actual instruction set used (for that, use -march=...).
>So it certainly should run.
>
>If you are aware that the man page is wrong in this respect, please
>tell us!

Wondering why one would use -mcpu and not -march.  If the code runs only on 
Celerons, PII's, and PIII's why would one *not* use -march.

I'm curious about (possible) breakages with -mcpu or -march compared to -Ox 
settings which seem to break things more often than -O.  Only ask, since 
-Ox and individual flags (rather than the mulititude added going from -O to 
-O2) are used far more often.


Jeff Mountin - [EMAIL PROTECTED]
Systems/Network Administrator
FreeBSD - the power to serve



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