Re: [PATCH] [2.4] [2.5] [i386] Add support for GCC 3.1 -march=pentium{-mmx,3,4}

[Dave Jones]

On Mon, May 27, 2002 at 08:53:02AM +0000, Pavel Machek wrote:
 > Hi!
 > 
 > > I would be (pleasantly) surprised to see gcc turn a C memcpy into faster
 > > assembly than our current implementation. And I'll bet
 > 
 > gcc has hand-coded assembly inside itself, if gcc compiled memcpy is slower
 > than hand-optimized one, you found a compiler bug.

Not at all. gcc compiled memcpy just has no knowledge of things like
non-temporal stores, and using mmx/sse to move 64 bits at a time instead
of 32 bit registers. (It's only recently it got prefetch abilities too).

-- 
| Dave Jones.        http://www.codemonkey.org.uk
| SuSE Labs