Justin C. Walker on Fri, 15 Dec 2006 22:22:07 +0100

[Date Prev] [Date Next] [Thread Prev] [Thread Next] [Date Index] [Thread Index]

Re: Lowering compiler optimisation with Apple gcc

On Dec 15, 2006, at 12:49 , Jason Martin wrote:

I've had excellent luck on my Core 2 Mac with the latest version of gcc using

  CFLAGS="-m64 -fast"

I've also ported and optimized GMP for Core 2 Macs, and using my port
of GMP I get Pari benchmarks on my Mac Pro that out perform all of the
Opteron machines I have access to.  For details, see my website (in my

I have not encountered any "bugs" in Apple's gcc, but I have
encountered "frustrations" because the Apple gcc options are not
compatible with the Linux options that I'm familiar with.

One subtle point of building for Core 2 Macs is that current versions
of the autoconf tools do not correctly detect the CPU type.  This is
because the "uname -m" command returns the rather unhelpful "i386"
rather than the "x86_64" that one might expect.  So, you have to
manually detect the CPU (Agner Fog has some nice routines for this).

Thanks for posting these tidbits.  They will prove useful.


Justin C. Walker, Curmudgeon at Large
Institute for the Enhancement of the Director's Income
Nobody knows the trouble I've been