[FFmpeg-cvslog] r12165 - trunk/libavcodec/dsputil.c

[Michael Niedermayer]

On Fri, Feb 22, 2008 at 12:44:13AM -0500, Rich Felker wrote:
> On Thu, Feb 21, 2008 at 10:35:53PM -0700, Loren Merritt wrote:
> > On Thu, 21 Feb 2008, Rich Felker wrote:
> > >
> > > The const keyword in C is not as strong as in C++. Historically it was
> > > just a hint for warning generation and binary sectioning. C99
> > > (possibly also C90?) add some teeth but I think it's still iffy to
> > > consider const-qualified variables as real constants. They're not
> > > usable in certain contexts where a constant is required.
> > 
> > It doesn't even have to be declared const.
> > "static unsigned long pb_7f = 0x7f7f7f7f7f7f7f7fUL" works too: gcc sees 
> > that it is never assigned to and thus is in fact constant. (assuming unit 
> > at a time, of course)
> 
> If I someday switch to gcc 4, -fno-unit-at-a-time is probably the only
> hope of building with <= 128 megs of ram. I'd rather not have
> gratuitous dependencies on unit-at-a-time for optimal code when it's
> trivial to write the optimal version directly.

I dont see why a properly written compiler would need 128mb ram to figure
out which static variables arent written to. grep is well capable of doing
that ...

[...]
-- 
Michael     GnuPG fingerprint: 9FF2128B147EF6730BADF133611EC787040B0FAB

Frequently ignored awnser#1 FFmpeg bugs should be sent to our bugtracker. User
questions about the command line tools should be sent to the ffmpeg-user ML.
And questions about how to use libav* should be sent to the libav-user ML.
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