From: Jeffrey A Law <law@hurl.cygnus.com>
To: barry@nibelung.demon.co.uk
Cc: egcs@cygnus.com
Subject: Re: Penitum II & egcs 1.1.1 oddity
Date: Sun, 31 Jan 1999 23:58:00 -0000 [thread overview]
Message-ID: <9723.917018431@hurl.cygnus.com> (raw)
Message-ID: <19990131235800.FrgQEELv5Ne4WCE9MPdsgN3XFLDGMQ4YQou_caZJ1TI@z> (raw)
In-Reply-To: <36A85F12.653EF986@nibelung.demon.co.uk>
In message < 36A85F12.653EF986@nibelung.demon.co.uk >you write:
> I've compiled egcs 1.1.1 having tried the standard 1.1.1 release and the
> 1.1.1 patched release. I've compiled on RedHat Linux 5.2 / PII 400. I
> compiled using 'configure --enable-shared --enable-haifa'.
>
> Is it normal that the compiler is sending -mcpu=pentiumpro but
> -march=pentium by default? For example, this is the output from 'gcc
> -fverbose-asm -S test.c'
Yes, this is normal.
It means schedule for a ppro, but generate (effectively) common-mode
instructions (ie your code can run on all x86 variants).
> Does it make a lot of difference compiling using -march=pentium as
> opposed to -march=pentiumpro on a Pentium II?
"a lot" is a relative term.
-march=pentiumpro will enable ppro specific instructions, namely conditional
moves, which for some code can be a nice improvement. For other code it won't
help in any noticable way. Just depends on your application.
jeff
next prev parent reply other threads:[~1999-01-31 23:58 UTC|newest]
Thread overview: 12+ messages / expand[flat|nested] mbox.gz Atom feed top
1999-01-22 3:18 Barry Shilliday
1999-01-22 7:24 ` Jeffrey A Law [this message]
1999-01-22 8:32 ` Barry
1999-01-22 8:56 ` Jeffrey A Law
1999-01-31 23:58 ` Jeffrey A Law
1999-01-31 23:58 ` Barry
1999-01-31 23:58 ` Jeffrey A Law
1999-01-31 23:58 ` Barry Shilliday
1999-01-22 19:05 N8TM
1999-01-23 5:36 ` Barry
1999-01-31 23:58 ` Barry
1999-01-31 23:58 ` N8TM
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