> -----Original Message-----
> From: Joseph Myers <jos...@codesourcery.com>
> Sent: Tuesday, May 11, 2021 6:01 PM
> To: David Brown <david.br...@hesbynett.no>
> Cc: Tamar Christina <tamar.christ...@arm.com>; gcc@gcc.gnu.org; Richard
> Sandiford <richard.sandif...@arm.com>; Richard Biener
> <rguent...@suse.de>
> Subject: Re: [RFC] Implementing detection of saturation and rounding
> arithmetic
>
> On Tue, 11 May 2021, David Brown wrote:
>
> > It is also worth noting that gcc already has support for saturating
> > types on some targets:
> >
> > <https://gcc.gnu.org/onlinedocs/gcc/Fixed-Point.html>
> >
> > My testing of these (quite a long time ago) left me with a feeling
> > that it was not a feature anyone had worked hard to optimise -
> > certainly it
>
> The implementation isn't well-integrated with any optimizations for
> arithmetic on ordinary integer types / modes, because it has its own
> completely separate machine modes and operations on those. I still think it
> would be better to have a GIMPLE pass that lowers from fixed-point types to
> saturating etc. operations on ordinary integer types, as I said in
> <https://gcc.gnu.org/legacy-ml/gcc-patches/2011-05/msg00846.html>.
>
Oh, thanks for the link! That's a very useful read!
Cheers,
Tamar
> Note however that such lowering should be more or less independent of
> what's being discussed in this thread - this thread is about better
> optimization of such operations on ordinary types (with or without built-in
> functions of some kind in addition to recognition of such operations written
> in generic C), which you can do independently of what's done with fixed-
> point types.
>
> --
> Joseph S. Myers
> jos...@codesourcery.com
