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Re: Compiler opt

On Sat, 2004-08-28 at 11:55 -0700, Karl Hegbloom wrote:
> On Sat, 2004-08-28 at 12:11 +0200, Sebastian Steinlechner wrote:
> > On Sat, 2004-08-28 at 02:22, Karl Hegbloom wrote:
> > > How do I determine the default compiler optimization settings?  I'm
> > > wonder if it will be worth while to try and recompile things like
> > > python2.3 and python2.3-numeric with '-m64'?  Or is '-m64' already the
> > > default?
> > 
> > If you're compiling on pure64, then you'll get 64-bit ELFs/libs (so -m64
> > is the default).
> Ok.  So then -m64 implies -march=k8 ?

It looks like you need to reverse that.  -march=k8 implies -m64.

From rom "man gcc-3.4":

           Tune to cpu-type everything applicable about the
           generated code, except for the ABI and the set
           of available instructions.  The choices for cpu-
           type are:
           k8, opteron, athlon64, athlon-fx
               AMD K8 core based CPUs with x86-64 instruc-
               tion set support.  (This supersets MMX, SSE,
               SSE2, 3dNOW!, enhanced 3dNOW! and 64-bit
               instruction set extensions.)

           Generate instructions for the machine type cpu-
           type.  The choices for cpu-type are the same as
           for -mtune.  Moreover, specifying -march=cpu-
           type implies -mtune=cpu-type.

           Generate code for a 32-bit or 64-bit environ-
           ment.  The 32-bit environment sets int, long and
           pointer to 32 bits and generates code that runs
           on any i386 system.  The 64-bit environment sets
           int to 32 bits and long and pointer to 64 bits
           and generates code for AMD's x86-64 architec-

Ron Johnson, Jr.
Jefferson, LA USA
PGP Key ID 8834C06B

"The UN couldn't break up a cookie fight in a Brownie meeting."
Larry Miller

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