From: Nathaniel Shead <nathanieloshead@gmail.com>
To: Nathan Sidwell <nathan@acm.org>
Cc: gcc-patches@gcc.gnu.org, Jason Merrill <jason@redhat.com>,
Patrick Palka <ppalka@redhat.com>
Subject: Re: [PATCH] c++/modules: Prevent overwriting arguments for duplicates [PR112588]
Date: Mon, 8 Jan 2024 01:29:30 +1100 [thread overview]
Message-ID: <659ab54e.630a0220.291d5.8735@mx.google.com> (raw)
In-Reply-To: <26aa9f6b-a015-4e6f-aa73-6912cbca50f6@acm.org>
On Sat, Jan 06, 2024 at 05:32:37PM -0500, Nathan Sidwell wrote:
> I;m not sure about this, there was clearly a reason I did it the way it is,
> but perhaps that reasoning became obsolete -- something about an existing
> declaration and reading in a definition maybe?
>
> nathan
So I took a bit of a closer look and this is actually a regression,
seeming to start with r13-3134-g09df0d8b14dda6. I haven't looked more
closely at the actual change though to see whether this implies a
different fix yet though.
Nathaniel
> On 11/22/23 06:33, Nathaniel Shead wrote:
> > Bootstrapped and regtested on x86_64-pc-linux-gnu. I don't have write
> > access.
> >
> > -- >8 --
> >
> > When merging duplicate instantiations of function templates, currently
> > read_function_def overwrites the arguments with that of the existing
> > duplicate. This is problematic, however, since this means that the
> > PARM_DECLs in the body of the function definition no longer match with
> > the PARM_DECLs in the argument list, which causes issues when it comes
> > to generating RTL.
> >
> > There doesn't seem to be any reason to do this replacement, so this
> > patch removes that logic.
> >
> > PR c++/112588
> >
> > gcc/cp/ChangeLog:
> >
> > * module.cc (trees_in::read_function_def): Don't overwrite
> > arguments.
> >
> > gcc/testsuite/ChangeLog:
> >
> > * g++.dg/modules/merge-16.h: New test.
> > * g++.dg/modules/merge-16_a.C: New test.
> > * g++.dg/modules/merge-16_b.C: New test.
> >
> > Signed-off-by: Nathaniel Shead <nathanieloshead@gmail.com>
> > ---
> > gcc/cp/module.cc | 2 --
> > gcc/testsuite/g++.dg/modules/merge-16.h | 10 ++++++++++
> > gcc/testsuite/g++.dg/modules/merge-16_a.C | 7 +++++++
> > gcc/testsuite/g++.dg/modules/merge-16_b.C | 5 +++++
> > 4 files changed, 22 insertions(+), 2 deletions(-)
> > create mode 100644 gcc/testsuite/g++.dg/modules/merge-16.h
> > create mode 100644 gcc/testsuite/g++.dg/modules/merge-16_a.C
> > create mode 100644 gcc/testsuite/g++.dg/modules/merge-16_b.C
> >
> > diff --git a/gcc/cp/module.cc b/gcc/cp/module.cc
> > index 4f5b6e2747a..2520ab659cc 100644
> > --- a/gcc/cp/module.cc
> > +++ b/gcc/cp/module.cc
> > @@ -11665,8 +11665,6 @@ trees_in::read_function_def (tree decl, tree maybe_template)
> > DECL_RESULT (decl) = result;
> > DECL_INITIAL (decl) = initial;
> > DECL_SAVED_TREE (decl) = saved;
> > - if (maybe_dup)
> > - DECL_ARGUMENTS (decl) = DECL_ARGUMENTS (maybe_dup);
> > if (context)
> > SET_DECL_FRIEND_CONTEXT (decl, context);
> > diff --git a/gcc/testsuite/g++.dg/modules/merge-16.h b/gcc/testsuite/g++.dg/modules/merge-16.h
> > new file mode 100644
> > index 00000000000..fdb38551103
> > --- /dev/null
> > +++ b/gcc/testsuite/g++.dg/modules/merge-16.h
> > @@ -0,0 +1,10 @@
> > +// PR c++/112588
> > +
> > +void f(int*);
> > +
> > +template <typename T>
> > +struct S {
> > + void g(int n) { f(&n); }
> > +};
> > +
> > +template struct S<void>;
> > diff --git a/gcc/testsuite/g++.dg/modules/merge-16_a.C b/gcc/testsuite/g++.dg/modules/merge-16_a.C
> > new file mode 100644
> > index 00000000000..c243224c875
> > --- /dev/null
> > +++ b/gcc/testsuite/g++.dg/modules/merge-16_a.C
> > @@ -0,0 +1,7 @@
> > +// PR c++/112588
> > +// { dg-additional-options "-fmodules-ts" }
> > +// { dg-module-cmi merge16 }
> > +
> > +module;
> > +#include "merge-16.h"
> > +export module merge16;
> > diff --git a/gcc/testsuite/g++.dg/modules/merge-16_b.C b/gcc/testsuite/g++.dg/modules/merge-16_b.C
> > new file mode 100644
> > index 00000000000..8c7b1f0511f
> > --- /dev/null
> > +++ b/gcc/testsuite/g++.dg/modules/merge-16_b.C
> > @@ -0,0 +1,5 @@
> > +// PR c++/112588
> > +// { dg-additional-options "-fmodules-ts" }
> > +
> > +#include "merge-16.h"
> > +import merge16;
>
> --
> Nathan Sidwell
>
next prev parent reply other threads:[~2024-01-07 14:29 UTC|newest]
Thread overview: 7+ messages / expand[flat|nested] mbox.gz Atom feed top
2023-11-22 11:33 Nathaniel Shead
2023-12-16 10:50 ` [PATCH] c++/modules: Prevent overwriting arguments when merging " Nathaniel Shead
2024-01-02 22:49 ` Nathaniel Shead
2024-01-06 22:32 ` [PATCH] c++/modules: Prevent overwriting arguments for " Nathan Sidwell
2024-01-07 14:29 ` Nathaniel Shead [this message]
2024-01-08 17:04 ` Patrick Palka
2024-01-17 16:28 ` Jason Merrill
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=659ab54e.630a0220.291d5.8735@mx.google.com \
--to=nathanieloshead@gmail.com \
--cc=gcc-patches@gcc.gnu.org \
--cc=jason@redhat.com \
--cc=nathan@acm.org \
--cc=ppalka@redhat.com \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for read-only IMAP folder(s) and NNTP newsgroup(s).