* Deprecating -fgnu-tm support for GCC 14 and removing it for GCC 15
@ 2023-12-16 20:15 Andrew Pinski
2023-12-17 16:26 ` Florian Weimer
2023-12-17 21:20 ` Eric Gallager
0 siblings, 2 replies; 7+ messages in thread
From: Andrew Pinski @ 2023-12-16 20:15 UTC (permalink / raw)
To: GCC Mailing List
-fgnu-tm support has not been improved since GCC 5 or earlier. It is
not even supported with LTO. Does it make sense to deprecate the
support for GCC 14 and remove it in GCC 15?
Thanks,
Andrew Pinski
^ permalink raw reply [flat|nested] 7+ messages in thread
* Re: Deprecating -fgnu-tm support for GCC 14 and removing it for GCC 15
2023-12-16 20:15 Deprecating -fgnu-tm support for GCC 14 and removing it for GCC 15 Andrew Pinski
@ 2023-12-17 16:26 ` Florian Weimer
2023-12-17 18:05 ` Andrew Pinski
2023-12-17 21:20 ` Eric Gallager
1 sibling, 1 reply; 7+ messages in thread
From: Florian Weimer @ 2023-12-17 16:26 UTC (permalink / raw)
To: Andrew Pinski via Gcc; +Cc: Andrew Pinski
* Andrew Pinski via Gcc:
> -fgnu-tm support has not been improved since GCC 5 or earlier. It is
> not even supported with LTO. Does it make sense to deprecate the
> support for GCC 14 and remove it in GCC 15?
Is this the stuff around libitm and that adds _ITM_registerTMCloneTable
and _ITM_deregisterTMCloneTable symbol references to *all* binaries
(whether they use transactional memory or not)?
Thanks,
Florian
^ permalink raw reply [flat|nested] 7+ messages in thread
* Re: Deprecating -fgnu-tm support for GCC 14 and removing it for GCC 15
2023-12-17 16:26 ` Florian Weimer
@ 2023-12-17 18:05 ` Andrew Pinski
0 siblings, 0 replies; 7+ messages in thread
From: Andrew Pinski @ 2023-12-17 18:05 UTC (permalink / raw)
To: Florian Weimer; +Cc: Andrew Pinski via Gcc
On Sun, Dec 17, 2023 at 8:26 AM Florian Weimer <fweimer@redhat.com> wrote:
>
> * Andrew Pinski via Gcc:
>
> > -fgnu-tm support has not been improved since GCC 5 or earlier. It is
> > not even supported with LTO. Does it make sense to deprecate the
> > support for GCC 14 and remove it in GCC 15?
>
> Is this the stuff around libitm and that adds _ITM_registerTMCloneTable
> and _ITM_deregisterTMCloneTable symbol references to *all* binaries
> (whether they use transactional memory or not)?
Yes. and the front-end support for it.
Thanks,
Andrew
>
> Thanks,
> Florian
>
^ permalink raw reply [flat|nested] 7+ messages in thread
* Re: Deprecating -fgnu-tm support for GCC 14 and removing it for GCC 15
2023-12-16 20:15 Deprecating -fgnu-tm support for GCC 14 and removing it for GCC 15 Andrew Pinski
2023-12-17 16:26 ` Florian Weimer
@ 2023-12-17 21:20 ` Eric Gallager
2023-12-18 1:33 ` Andrew Pinski
1 sibling, 1 reply; 7+ messages in thread
From: Eric Gallager @ 2023-12-17 21:20 UTC (permalink / raw)
To: Andrew Pinski; +Cc: GCC Mailing List
On Sat, Dec 16, 2023 at 3:16 PM Andrew Pinski via Gcc <gcc@gcc.gnu.org> wrote:
>
> -fgnu-tm support has not been improved since GCC 5 or earlier. It is
> not even supported with LTO. Does it make sense to deprecate the
> support for GCC 14 and remove it in GCC 15?
>
> Thanks,
> Andrew Pinski
Personally, since GCC is in stage 3 now, I would push that schedule
back a release and move deprecation to GCC 15, and then only remove it
for GCC 16 if no one objects, but then again I don't actually use
-fgnu-tm myself, so I wouldn't be too upset if the faster schedule is
chosen instead.
Eric Gallager
^ permalink raw reply [flat|nested] 7+ messages in thread
* Re: Deprecating -fgnu-tm support for GCC 14 and removing it for GCC 15
2023-12-17 21:20 ` Eric Gallager
@ 2023-12-18 1:33 ` Andrew Pinski
2023-12-18 8:01 ` Richard Biener
0 siblings, 1 reply; 7+ messages in thread
From: Andrew Pinski @ 2023-12-18 1:33 UTC (permalink / raw)
To: Eric Gallager; +Cc: GCC Mailing List
On Sun, Dec 17, 2023 at 1:20 PM Eric Gallager <egall@gwmail.gwu.edu> wrote:
>
> On Sat, Dec 16, 2023 at 3:16 PM Andrew Pinski via Gcc <gcc@gcc.gnu.org> wrote:
> >
> > -fgnu-tm support has not been improved since GCC 5 or earlier. It is
> > not even supported with LTO. Does it make sense to deprecate the
> > support for GCC 14 and remove it in GCC 15?
> >
> > Thanks,
> > Andrew Pinski
>
> Personally, since GCC is in stage 3 now, I would push that schedule
> back a release and move deprecation to GCC 15, and then only remove it
> for GCC 16 if no one objects, but then again I don't actually use
> -fgnu-tm myself, so I wouldn't be too upset if the faster schedule is
> chosen instead.
Considering -fgnu-tm has been broken for LTO ever since LTO was
introduced, and broken with -fsanitize=undefined and broken with many
code that might use internal functions (known since 2015), I suspect
nobody is using this option in production nor even trying it out. If
this was stage1, I might even just recommend removing the support. But
deprecating it during stage 3 seems like a fair compromise.
> Eric Gallager
^ permalink raw reply [flat|nested] 7+ messages in thread
* Re: Deprecating -fgnu-tm support for GCC 14 and removing it for GCC 15
2023-12-18 1:33 ` Andrew Pinski
@ 2023-12-18 8:01 ` Richard Biener
2023-12-20 16:40 ` Jason Merrill
0 siblings, 1 reply; 7+ messages in thread
From: Richard Biener @ 2023-12-18 8:01 UTC (permalink / raw)
To: Andrew Pinski; +Cc: Eric Gallager, GCC Mailing List
On Mon, Dec 18, 2023 at 2:35 AM Andrew Pinski via Gcc <gcc@gcc.gnu.org> wrote:
>
> On Sun, Dec 17, 2023 at 1:20 PM Eric Gallager <egall@gwmail.gwu.edu> wrote:
> >
> > On Sat, Dec 16, 2023 at 3:16 PM Andrew Pinski via Gcc <gcc@gcc.gnu.org> wrote:
> > >
> > > -fgnu-tm support has not been improved since GCC 5 or earlier. It is
> > > not even supported with LTO. Does it make sense to deprecate the
> > > support for GCC 14 and remove it in GCC 15?
> > >
> > > Thanks,
> > > Andrew Pinski
> >
> > Personally, since GCC is in stage 3 now, I would push that schedule
> > back a release and move deprecation to GCC 15, and then only remove it
> > for GCC 16 if no one objects, but then again I don't actually use
> > -fgnu-tm myself, so I wouldn't be too upset if the faster schedule is
> > chosen instead.
>
> Considering -fgnu-tm has been broken for LTO ever since LTO was
> introduced, and broken with -fsanitize=undefined and broken with many
> code that might use internal functions (known since 2015), I suspect
> nobody is using this option in production nor even trying it out. If
> this was stage1, I might even just recommend removing the support. But
> deprecating it during stage 3 seems like a fair compromise.
Btw, I'm OK with deprecating it for GCC 14. Can you please propose a
patch for changes.html and add a diagnostic message when -fgnu-tm is used
(disabled with -Wno-deprecated)?
Thanks,
Richard.
> > Eric Gallager
^ permalink raw reply [flat|nested] 7+ messages in thread
* Re: Deprecating -fgnu-tm support for GCC 14 and removing it for GCC 15
2023-12-18 8:01 ` Richard Biener
@ 2023-12-20 16:40 ` Jason Merrill
0 siblings, 0 replies; 7+ messages in thread
From: Jason Merrill @ 2023-12-20 16:40 UTC (permalink / raw)
To: Richard Biener; +Cc: Andrew Pinski, Eric Gallager, GCC Mailing List
[-- Attachment #1: Type: text/plain, Size: 1986 bytes --]
On Mon, Dec 18, 2023 at 3:04 AM Richard Biener via Gcc <gcc@gcc.gnu.org>
wrote:
> On Mon, Dec 18, 2023 at 2:35 AM Andrew Pinski via Gcc <gcc@gcc.gnu.org>
> wrote:
> >
> > On Sun, Dec 17, 2023 at 1:20 PM Eric Gallager <egall@gwmail.gwu.edu>
> wrote:
> > >
> > > On Sat, Dec 16, 2023 at 3:16 PM Andrew Pinski via Gcc <gcc@gcc.gnu.org>
> wrote:
> > > >
> > > > -fgnu-tm support has not been improved since GCC 5 or earlier. It is
> > > > not even supported with LTO. Does it make sense to deprecate the
> > > > support for GCC 14 and remove it in GCC 15?
> > > >
> > > > Thanks,
> > > > Andrew Pinski
> > >
> > > Personally, since GCC is in stage 3 now, I would push that schedule
> > > back a release and move deprecation to GCC 15, and then only remove it
> > > for GCC 16 if no one objects, but then again I don't actually use
> > > -fgnu-tm myself, so I wouldn't be too upset if the faster schedule is
> > > chosen instead.
> >
> > Considering -fgnu-tm has been broken for LTO ever since LTO was
> > introduced, and broken with -fsanitize=undefined and broken with many
> > code that might use internal functions (known since 2015), I suspect
> > nobody is using this option in production nor even trying it out. If
> > this was stage1, I might even just recommend removing the support. But
> > deprecating it during stage 3 seems like a fair compromise.
>
> Btw, I'm OK with deprecating it for GCC 14. Can you please propose a
> patch for changes.html and add a diagnostic message when -fgnu-tm is used
> (disabled with -Wno-deprecated)?
>
Deprecation makes sense to me.
But keep in mind that transactional memory is still the subject of research
and standardization efforts, though the current proposal (wg21.link/n4923)
is significantly simpler than the earlier TS that GCC implemented. I don't
know how much of the current implementation would carry over, but I'd be
cautious about tearing everything out just yet.
Jason
^ permalink raw reply [flat|nested] 7+ messages in thread
end of thread, other threads:[~2023-12-20 16:41 UTC | newest]
Thread overview: 7+ messages (download: mbox.gz / follow: Atom feed)
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2023-12-16 20:15 Deprecating -fgnu-tm support for GCC 14 and removing it for GCC 15 Andrew Pinski
2023-12-17 16:26 ` Florian Weimer
2023-12-17 18:05 ` Andrew Pinski
2023-12-17 21:20 ` Eric Gallager
2023-12-18 1:33 ` Andrew Pinski
2023-12-18 8:01 ` Richard Biener
2023-12-20 16:40 ` Jason Merrill
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