On Tuesday 22 November 2005 21:18, Scott Robert Ladd wrote: > Jan Hubicka wrote: > > I should note that comparison to ICC is not quite fair since it lacks > > Opteron tunning... > > I think you may be comparing oranges to tangerines -- not as bad as > apples and oranges, but still potentially an invalid comparison. > > In my experience the extra registers of the Opteron provide a > significant benefit; GCC has an unfair advantage if ICC only generated > code for the small set of x86 registers.
It obviously doesn't do that. ICC uses that larger register file, too, for x86-64. AMD's Opteron (AMD64) and Intel's Nocona (EM64T-cheap-ass-AMD64-clone) are both just implementations of the x86-64 architecture. And ICC is tuned for EM64T, I would guess. GCC is tuned for AMD64. But both compilers compile for x86-64, so both compilers use the larger register file. Gr. Steven
