rawhide report: 20050510 changes

[Jakub Jelinek]

On Tue, May 10, 2005 at 05:08:34PM +0200, Nils Philippsen wrote:
> > If the only place that you want to enable -msse2 for are the clobber
> > lists of __asm statements, then perhaps best would be to conditionalize
> > them:
> > __asm ("something" : ... : ... :
> > #ifdef __SSE2__
> > "xmm0", "xmm1"
> > #endif
> > );
> > etc., because without -msse2 (resp. -msse (__SSE__ macro)), the registers
> > are not known to the compiler, so there is no point to tell the compiler
> > about them.
> 
> Ahh. If I understand you correctly, given that the various asm optimized
> functions are in separate source files, it should be ensured that 
> -mmmx/sse/sse2/3dnow are used only for the relevant source files?

Yes (and assuming they don't also contain code that is called
unconditionally).
Or don't pass -mmmx/-msse/-msse2/-m3dnow etc. at all, and hide all the
SSE2 etc. stuff in __asm and conditionally don't expose the clobbers
to GCC.

	Jakub