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

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

On Tue, Nov 22, 2022 at 2:40 PM Aldy Hernandez <aldyh@redhat.com> wrote:
>
>
>
> On 11/22/22 10:22, Richard Biener wrote:
> > 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.
>
> Documented and added change log entries.  Retested on x86-64 Linux.
>
> There are three follow-up patches removing ASSERT_EXPR which I'll post
> shortly.
>
> OK for trunk?

OK.

Thanks,
Richard.

> Aldy