[Ffmpeg-devel] mmx/sse optimizations

Rich Felker dalias
Fri Dec 23 18:54:40 CET 2005

On Fri, Dec 23, 2005 at 08:38:42AM +0100, Luca Barbato wrote:
> Rich Felker wrote:
> >>
> >>	SIMD code is a different beast than normal ASM. I think this tool 
> >>	has its place. Perhaps another idea would be a tool that enables the 
> >>	user to describe some kind of general algorithm with a set of SIMD-like 
> >>primitives.
> ...
> >>Then the tool decides what the equivalent code would look 
> >>like using different SIMD sets (MMX, SSE2, AltiVec) AND can output the 
> >>correct ASM syntax for use in gcc and MSVC.
> >
> >
> >Hmm, sounds a lot like vector intrinsics. IMO they're a trap that lead
> >to people making simd code that's 5-25% slower than handwritten asm.
> Prove it on non flawed SIMD and non flawed CC. I'm quite sure nobody 

There is no such thing as non-flawed gcc. Look at all of Michael's
tests showing gcc generating shit code where the correct code is
totally obvious. If you're volunteering to write a new compiler that's
free and doesn't suck then you're entitled to talk trash like this
("prove it!" ...) otherwise STFU. :)


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