On Sun, Jun 24, 2007 at 03:15:17PM -0700, Arjan van de Ven wrote: > > > > I think all these benefits are the gcc's __builtin_memset optimization > > > than the explicit call to memset. > > > > ... or from complex memset() implementation (some chips even didn't do > > `rep' fast enough somehow). Maybe code like below will be acceptable for > > both optimizers and maintainers? > > > we should just alias our memset to the __builtin one, and then provide a > generic one from lib/ for the cases gcc needs to do a fallback.
In x86_64 there's infrastructure to check and select right memset(). Therefor it's need, i think. But if one will took a look at usage, zero memset() optimization becomes obvious, one argument off -- one reg is free from clobbering. |-*- flower-:22-rc4-mm2/arch/x86_64$ grep memset -R . | grep "[ 0,]0," | wc -l 42 flower-:22-rc4-mm2/arch/x86_64$ flower-:22-rc4-mm2/arch/x86_64$ cd .. flower-:22-rc4-mm2/arch$ grep memset -R . | grep "[ 0,]0," | wc -l 735 flower-:22-rc4-mm2/arch$ flower-:22-rc4-mm2$ grep memset -R . | grep "[ 0,]0," | wc -l 6679 flower-:22-rc4-mm2$ |-*- ____ - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to [EMAIL PROTECTED] More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
