Re: [avr-gcc-list] Re: AVR byte swap optimization

[Steven Bosscher]

On 11/19/06, Eric Weddington <address@hidden> wrote:
> > Use gcc head, __builtin_bswap and make sure the AVR backend
> > implements the
> > bswap rtl patterns.
>
> There's the problem. You can't just glibly say "make sure the AVR backend
> implements the bswap rtl patterns". There are precious few volunteers who
> are familiar enough with gcc internals and the avr port in particular to go
> do just that. AFAIK, there is no bswap rtl pattern in the avr port, at least
> there doesn't seem to be in 4.1.1.

Why is that a problem?
Do you have a different solution in mind?

> > Future versions of gcc may also be able to recognise these
> > idioms without
> > using the builtin, but AFAIK that's not been implemented yet.
>
> Plus there is a long lead time between when it is implemented on HEAD, then
> branched, released from a branch, and then when it shows up in binary
> distributions.

That happens with all improvements that are implemented between
releases, so I don't see your point.

Gr.
Steven