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Subject: RE: possible compiler optimization error
Date: Thu, 28 Jun 2007 16:11:18 -0400
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From: "Frederich, Eric P21322" <eric DOT frederich AT siemens DOT com>
To: <cygwin AT cygwin DOT com>
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> -----Original Message-----
> From: cygwin-owner AT cygwin DOT com On Behalf Of Brian Dessent
> Sent: Thursday, June 28, 2007 3:42 PM
> To: cygwin AT cygwin DOT com
> Subject: Re: possible compiler optimization error
> 
>
> But both of these are too new to be in Cygwin's gcc 3.4.x so this is
> kind of off-topic.
> 
> Brian
> 

To bring things back on topic.  The programs I am porting from Solaris
to Linux and Windows need to run on a variety of hardware.  Without
using -march and creating different libraries and binaries for each
piece of hardware, what would a good set of compiler options be?

You said that combining -march=i686 and -msse2 didn't make too much
sense.
So without setting -march, what all should I be setting?
On my laptop with CPU-Z I see MMX, SSE, and SSE2.
On my Opteron Linux box I obviously see a lot more when I cat
/proc/cpuinfo.

If I just use what is common between them, -mmmx, -msse, and -msse2 I
should be free of floating point errors and hopefully get some
performance increase.  Should I be using -mmmx if I'm also using -msse
and -msse2?

I am comfortable locking out users without sse and sse2 since most of
our users are using computers that are no more than 2 or 3 years old.

Again, thanks a lot for your help.

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