Re: [PATCH] libstdc++: Fix compare_three_way for constexpr and Clang

[Paul Keir <Paul.Keir@uws.ac.uk>]

I'd like to cancel the request to apply that patch.

At the time I had actually assumed that Clang was at fault, but your comment made me pause. I'll submit a bug report as you suggest. We can reconsider the patch in future once that bug is resolved.

________________________________________
From: Jonathan Wakely <jwakely@redhat.com>
Sent: 11 October 2021 22:04
To: Paul Keir
Cc: gcc-patches@gcc.gnu.org; libstdc++@gcc.gnu.org
Subject: Re: [PATCH] libstdc++: Fix compare_three_way for constexpr and Clang

The source of this email is EXTERNAL to UWS

On Mon, 11 Oct 2021 at 20:48, Jonathan Wakely <jwakely@redhat.com> wrote:
>
> On Fri, 20 Aug 2021 at 21:19, Paul Keir wrote:
> >
> > Hi,
> >
> > The current compare_three_way implementation makes provision for constant evaluation contexts (avoiding reinterpret_cast etc.), but the approach fails with Clang; when it compares two const volatile void pointers: "comparison between unequal pointers to void has unspecified result". I include a fix and test.
> >
> > Could someone commit the attached patch for me?
>
> Sorry for dropping the ball on this again. I've applied the patch
> locally and I'm testing it now. Unless I'm mistaken, you do not have a
> copyright assignment on file with the FSF, is that right? Are you able
> to certify that you have the right to submit this to GCC, as described
> at https://eu-west-1.protection.sophos.com?d=gnu.org&u=aHR0cHM6Ly9nY2MuZ251Lm9yZy9kY28uaHRtbA==&i=NWY2MGNhZjMzZTA5NzkwZGZlNmJhMzUy&t=SlR2SzN4czZueWZRZGdubVA0Z2M4M2FGbC9YLzIrWEVZaUpTMEhaZUJLND0=&h=929febb5b144486493bd3fc3c8522cfe ?

P.S. patches should not touch the ChangeLog file. It was always wrong,
because it usually makes the patch fail to apply. Since we moved to
Git the ChangeLog files are automatically generated from the Git
commits anyway, so are never touched as part of the commit. The
changelog entry is still needed, but should be in the Git commit
message not as a patch against the actual ChangeLog file.

>
> Also, if GCC is failing to diagnose the invalid comparisons here then
> that should be reported to bugzilla as a c++ "accepts-invalid" bug.



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