On Sun, Feb 21, 2010 at 10:59:05PM +0100, Steven Bosscher wrote: > On Sun, Feb 21, 2010 at 10:07 PM, Erik Trulsson <ertr1...@student.uu.se> > wrote: > >> There is nothing which stops them from using -march=i386. It just may not > >> be the default. > > > > That argument cuts both ways you know. There is nothing stopping > > people with the latest CPUs from using -march= to get code optimised > > for their hardware. It just may not be the default. > > Which brings us back to the discussion of satisfying the needs of a > tiny minority while hurting the vast majority of users. I prefer to > satisfy the need of the majority.
That would depend on how large the majority is compared to the minority and how much they will be hurt in the respective cases. As for the relative sizes of the groups, the above comments were in context of using SSE2 by default. I do not believe that the vast majority of x86 CPUs currently in use do support SSE2. A majority of them, possibly, but not a vast majority. As for the relative hurts. Code compiled for a newer CPU (making use of newer instructions) will not run at all on older CPUs not supporting those newer instructions. Much hurt there. On the other hand code compiled for an older CPU that is run a newer CPU will run just fine, if slightly slower than they could have due to not making use of new instructions in the newer CPU. For most programs the performance increase of re-compiling for the newer CPU would be barely noticable so the hurt of not having that is very little. -- <Insert your favourite quote here.> Erik Trulsson ertr1...@student.uu.se
