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From: "H. Peter Anvin" <hpa@zytor.com>
To: linux-kernel@vger.kernel.org
Subject: Re: [BK+PATCH] remove __constant_memcpy
Date: 17 Apr 2003 13:01:52 -0700	[thread overview]
Message-ID: <b7n17g$dlp$1@cesium.transmeta.com> (raw)
In-Reply-To: 1050585430.31390.32.camel@dhcp22.swansea.linux.org.uk

Followup to:  <1050585430.31390.32.camel@dhcp22.swansea.linux.org.uk>
By author:    Alan Cox <alan@lxorguk.ukuu.org.uk>
In newsgroup: linux.dev.kernel
> 
> You are assuming the compiler is smart about stuff - it doesnt know
> SSE/MMX for page copies etc. For small copies it should alays win, but
> isn't it best if so to use __builtin_memcpy without our existing
> macros not just trust the compiler ?
> 

For large or variable-sized copies __builtin_memcpy() just generates a
call to memcpy().  What's more, if you don't specify
-fno-builtin-memcpy memcpy() defaults to __builtin_memcpy()
automatically unless you override it (which Linux does with its
macros.)

	-hpa

-- 
<hpa@transmeta.com> at work, <hpa@zytor.com> in private!
"Unix gives you enough rope to shoot yourself in the foot."
Architectures needed: ia64 m68k mips64 ppc ppc64 s390 s390x sh v850 x86-64

  parent reply	other threads:[~2003-04-17 19:50 UTC|newest]

Thread overview: 27+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2003-04-17  0:57 [BK+PATCH] remove __constant_memcpy Jeff Garzik
2003-04-17  1:04 ` Jeff Garzik
2003-04-17  2:06 ` Linus Torvalds
2003-04-17  8:46   ` Arjan van de Ven
2003-04-17  9:02     ` Roman Zippel
2003-04-17  9:04       ` Arjan van de Ven
2003-04-17  9:11         ` Jakub Jelinek
2003-04-17 16:07     ` Linus Torvalds
2003-04-17 19:07       ` Jeff Garzik
2003-04-17 19:19       ` Jeff Garzik
2003-04-17 19:54         ` Linus Torvalds
2003-04-17 23:49           ` Jeff Garzik
2003-04-17 23:52             ` Jeff Garzik
2003-04-17 23:59             ` Linus Torvalds
2003-04-18  0:29               ` H. Peter Anvin
2003-04-18  9:06             ` Arjan van de Ven
2003-04-18 14:31             ` Timothy Miller
2003-04-18 15:07               ` Richard B. Johnson
2003-04-17 22:58         ` J.A. Magallon
2003-04-17 23:10           ` Jeff Garzik
2003-04-17 13:17 ` Alan Cox
2003-04-17 13:17 ` Alan Cox
2003-04-17 14:32   ` Jeff Garzik
2003-04-17 14:40     ` Jeff Garzik
2003-04-17 20:01   ` H. Peter Anvin [this message]
  -- strict thread matches above, loose matches on Subject: below --
2003-04-17  2:22 Nakajima, Jun
2003-04-17 23:50 Chuck Ebbert

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