On Wed, Aug 09, 2006 at 07:32:48AM -0500, Tim & Alethea Larson wrote:
> What kind of gains does one see optimizing for a specific processor as 
> opposed to a processor family?  Just curious.

That depends a lot on the processors & families involved.  In a case
such as this where the 68060 has to handle some 68k instructions by
emulation, optimizing for the 68060 (and avoiding those instructions)
can make a huge difference.  In some other cases where some instructions
or instruction sequences are more efficient on a given processor and gcc
is aware of that, you'll get some gain--but the actual gain depends on
how much the code can be affected by those differences.  In long-lived
processor families, there are some pretty wide differences in what each
processor does well.

I expect that there's some literature out there on it, but it's not
an area I've studied.

-allen

-- 
Allen Briggs  |  http://www.ninthwonder.com/~briggs/  |  briggs@ninthwonder.com