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RE: "SSE instruction set disabled?"
- From: "Scott Robert Ladd" <scott at coyotegulch dot com>
- To: "R. Kelley Cook" <robert_k_cook at comerica dot com>, <gcc at gcc dot gnu dot org>
- Date: Wed, 4 Dec 2002 14:26:00 -0500
- Subject: RE: "SSE instruction set disabled?"
R. Kelly Cook wrote:
> "-mmmx", "-msse", "-msse2", and "-m3dnow" (and their coresponding
> -mno-xxx) should just go away.
>
> They already are implied by -march=blahblah that we have. If someone
> wants code tuned for a pentium4, but without any SSE or MMX support then
> they can type "-march=pentiumpro -mcpu=pentium4"
I very much like this idea. The number of command-line options is very
confusing; anything that can rationally be done to simplify matters would be
in porgrammers' and gcc's) best interest.
> Although, in my opinion "-mcpu=" should be renamed "-mtune=" like was
> debated ages ago: http://gcc.gnu.org/ml/gcc/1999-01n/msg01004.html
The gcc docs state: "Moreover, specifying -march=cpu-type
implies -mcpu=cpu-type." That suggests that assuming "-msse" and such is
reasonable.
BTW, why would someone set "-mcpu" different from "-march" anyway? Why two
switches? Why wouldn't it be a good idea to always "tune" for the chosen
architecture?
..Scott