Re: [BK+PATCH] remove __constant_memcpy

Arjan van de Ven (arjanv@redhat.com)
17 Apr 2003 10:46:47 +0200


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On Thu, 2003-04-17 at 04:06, Linus Torvalds wrote:
> On Wed, 16 Apr 2003, Jeff Garzik wrote:
> >=20
> > gcc's __builtin_memcpy performs the same function (and more) as the=20
> > kernel's __constant_memcpy. So, let's remove __constant_memcpy, and le=
t=20
> > the compiler do it.
>=20
> Please don't.
>=20
> There's no way gcc will EVER get the SSE2 cases right. It just cannot do=20
> it. In fact, I live in fear that we will have to turn off the compiler=20
> intrisics entirely some day just because there is always the worry that=20
> gcc will start using FP.

it can do that ANYWAY for all kinds of things.
We really should ask the gcc folks to add a
-fdontyoudareusefloatingpoint flag (well different name probably) to
make sure it never ever will generate FP code. (would also help catch
abusers of FP code in the kernel as a bonus ;)

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