Re: [PATCH][1/2] Move mult synthesis definitions into a separate file

[Kyrill Tkachov <kyrylo dot tkachov at foss dot arm dot com>]

Hi Richard,

On 13/06/16 15:07, Richard Biener wrote:
> On Mon, Jun 13, 2016 at 2:23 PM, Kyrill Tkachov
> <kyrylo.tkachov@foss.arm.com> wrote:
> > Hi all,
> >
> > There are other places besides expand where we might want to synthesize an
> > integer
> > multiplication by a constant.  Thankfully the algorithm selection code in
> > expmed.c
> > is already quite well separated from the RTL implementation, so if we can
> > just factor
> > out the prototype of choose_mult_variant and some enums and structs that it
> > needs into
> > a separate header file we can reuse them from other parts of the compiler.
> >
> > I need this for patch 2/2 which hooks up the vectorizer to synthesize vector
> > multiplications using sequences of shifts and other arithmetic ops when
> > appropriate.
> >
> > The new header is called mult-synthesis.h. Should I add it to some makefile?
> > grepping around for a bit I'm not sure what to do about it.
> Possibly PLUGIN_HEADERS.

Ok.

> You could have included expmed.h from the vectorizer, no?  After all this
> patch now breaks that things declared in A.h are defined in A.c as you
> didn't move choose_mult_variant itself.

I think including expmed.h would work. I thought it defined too many
irrelevant RTL-specific things that you wouldn't want in the vectoriser.
If you don't mind I'm happy to just include expmed.h.
Do we have a rule for defining things delcared in A.h in A.c?
I notice we declare various extern things in rtl.h that aren't defined in
rtl.c, though I suppose that would be an exception...

Thanks,
Kyrill

> Thanks,
> Richard.
>
> > Bootstrapped and tested on arm, aarch64, x86_64.
> >
> > Thanks,
> > Kyrill
> >
> > 2016-06-13  Kyrylo Tkachov  <kyrylo.tkachov@arm.com>
> >
> >      * mult-synthesis.h: New file.  Add choose_mult_variant prototype.
> >      * expmed.h: Include mult-synthesis.h
> >      (enum alg_code): Move to mult-synthesis.h
> >      (struct mult_cost): Likewise.
> >      (struct algorithm): Likewise.
> >      * expmed.c (enum mult_variant): Move to mult-synthesis.h
> >      (choose_mult_variant): Delete prototype.  Remove static qualifier.