Re: [PATCH] Remove legacy VRP (maybe?)

[Richard Biener <richard.guenther@gmail.com>]

On Tue, Nov 22, 2022 at 10:04 AM Aldy Hernandez <aldyh@redhat.com> wrote:
>
>
>
> On 11/22/22 09:25, Richard Biener wrote:
> > On Tue, Nov 22, 2022 at 9:24 AM Richard Biener
> > <richard.guenther@gmail.com> wrote:
> >>
> >> On Mon, Nov 21, 2022 at 5:49 PM Jeff Law <jeffreyalaw@gmail.com> wrote:
> >>>
> >>>
> >>> On 11/21/22 09:35, Aldy Hernandez via Gcc-patches wrote:
> >>>> I've been playing around with removing the legacy VRP code for the
> >>>> next release.  It's a layered onion to get this right, but the first
> >>>> bit is pretty straightforward and may be useful for this release.
> >>>> Basically, it entails removing the old VRP pass itself, along with
> >>>> value_range_equiv which have no producers left.  The current users of
> >>>> value_range_equiv don't put anything in the equivalence bitmaps, so
> >>>> they're basically behaving like plain value_range.
> >>>>
> >>>> I removed as much as possible without having to change any behavior,
> >>>> and this is what I came up with.  Is this something that would be
> >>>> useful for this release?  Would it help release managers have less
> >>>> unused cruft in the tree?
> >>>>
> >>>> Neither Andrew nor I have any strong feelings here.  We don't foresee
> >>>> the legacy code changing at all in the offseason, so we can just
> >>>> accumulate these patches in local trees.
> >>>
> >>> I'd lean towards removal after gcc-13 releases.
> >>
> >> I think removing the ability to switch to the old implementation easens
> >> maintainance so I'd prefer to have this before the gcc-13 release.
> >>
> >> So please go ahead.
> >
> > Btw, ASSERT_EXPR should also go away with this, no?
>
> Ah yes, for everything except ipa-*.* which uses it internally (and sets
> it in its internal structures):
>
>         - ASSERT_EXPR means that only the value in operand is allowed to
> pass
>           through (without any change), for all other values the result is
>           unknown.

Ick.  But yeah, I can see how 'ASSERT_EXPR' looked nice to use here
(but it's only a distinct value, so TARGET_OPTION_NODE would have
worked here as well)

> I can remove all other uses, including any externally visible documentation.

Works for me.

Richard.

> Thanks.
> Aldy
>