From: Richard Biener <rguenther@suse.de>
To: Jason Merrill <jason@redhat.com>
Cc: Bernd Edlinger <bernd.edlinger@hotmail.de>,
Jakub Jelinek <jakub@redhat.com>,
Jonathan Wakely <jwakely@redhat.com>,
Florian Weimer <fweimer@redhat.com>,
GCC Patches <gcc-patches@gcc.gnu.org>,
Jeff Law <law@redhat.com>
Subject: Re: [PATCH] Add a new type attribute always_alias (PR79671)
Date: Mon, 10 Apr 2017 15:31:00 -0000 [thread overview]
Message-ID: <alpine.LSU.2.20.1704101727290.30715@zhemvz.fhfr.qr> (raw)
In-Reply-To: <CADzB+2mA9=K-=rerbXviq99Gg_3K1gmuE7kNsX2FfTcr_kcYXQ@mail.gmail.com>
On Mon, 10 Apr 2017, Jason Merrill wrote:
> On Mon, Apr 10, 2017 at 8:50 AM, Richard Biener <rguenther@suse.de> wrote:
> > So here's my variant of a fix. I constrained the new flag
> > TYPE_TYPELESS_STORAGE to arrays and thus hope my localized fix in
> > build_cplus_array_type will suffice (if I have time I'll play with
> > template instantiation).
>
> Looks good. I would expect this to just work with templates, but it
> should of course be tested. In particular, std::aligned_storage needs
> to work.
The libstdc++ testsuite passes... (of course it did before as well).
I'll experiment with some trivial bits tomorrow.
> > * tree.c (build_cplus_array_type): Set TYPE_TYPELESS_STORAGE
> > for arrays of unsigned char or std::byte.
>
> I think it would be good to have a flag to select whether these
> semantics apply to any char variant and std::byte, only unsigned char
> and std::byte, or only std::byte.
Any suggestion? Not sure we really need it (I'm hesitant to write
all the testcases to verify it actually works).
Meanwhile re-testing with the following hunk to fix some LTO fallout.
Richard.
Index: gcc/tree.h
===================================================================
--- gcc/tree.h (revision 246808)
+++ gcc/tree.h (working copy)
@@ -4914,7 +4917,7 @@ inline bool
canonical_type_used_p (const_tree t)
{
return !(POINTER_TYPE_P (t)
- || TREE_CODE (t) == ARRAY_TYPE
+ || (TREE_CODE (t) == ARRAY_TYPE && ! TYPE_TYPELESS_STORAGE (t))
|| TREE_CODE (t) == VECTOR_TYPE);
}
next prev parent reply other threads:[~2017-04-10 15:31 UTC|newest]
Thread overview: 65+ messages / expand[flat|nested] mbox.gz Atom feed top
2017-04-05 9:46 Bernd Edlinger
2017-04-05 13:28 ` Jakub Jelinek
2017-04-05 15:20 ` Richard Biener
2017-04-05 17:41 ` Bernd Edlinger
2017-04-05 20:18 ` Jason Merrill
2017-04-05 20:46 ` Bernd Edlinger
2017-04-05 22:54 ` Pedro Alves
2017-04-06 10:08 ` Jonathan Wakely
2017-04-06 7:23 ` Richard Biener
2017-04-05 15:27 ` Bernd Edlinger
2017-04-05 15:29 ` Jakub Jelinek
2017-04-05 14:50 ` Florian Weimer
2017-04-05 15:23 ` Richard Biener
2017-04-05 15:38 ` Bernd Edlinger
2017-04-05 16:03 ` Jonathan Wakely
2017-04-05 16:08 ` Jakub Jelinek
2017-04-05 17:23 ` Bernd Edlinger
2017-04-05 21:02 ` Bernd Edlinger
2017-04-05 23:17 ` Sandra Loosemore
2017-04-06 5:40 ` Jakub Jelinek
2017-04-06 7:47 ` Richard Biener
2017-04-06 7:51 ` Jakub Jelinek
2017-04-06 7:55 ` Richard Biener
2017-04-06 14:11 ` Bernd Edlinger
2017-04-06 14:17 ` Florian Weimer
2017-04-06 14:23 ` Richard Biener
2017-04-06 14:43 ` Jonathan Wakely
2017-04-06 14:51 ` Florian Weimer
2017-04-06 15:05 ` Jakub Jelinek
2017-04-06 15:10 ` Florian Weimer
2017-04-06 19:13 ` Richard Biener
2017-04-11 10:43 ` Florian Weimer
2017-04-11 10:48 ` Richard Biener
2017-04-06 17:39 ` Bernd Edlinger
2017-04-06 17:48 ` Florian Weimer
2017-04-06 18:12 ` Bernd Edlinger
2017-04-06 18:19 ` Florian Weimer
2017-04-06 18:49 ` Bernd Edlinger
2017-04-06 19:05 ` Florian Weimer
2017-04-06 19:20 ` Bernd Edlinger
2017-04-07 6:47 ` Richard Biener
2017-04-07 12:58 ` Bernd Edlinger
2017-04-06 19:16 ` Richard Biener
2017-04-07 6:56 ` Florian Weimer
2017-04-07 8:01 ` Richard Biener
2017-04-06 19:14 ` Richard Biener
2017-04-06 19:51 ` Bernd Edlinger
2017-04-06 14:22 ` Richard Biener
2017-04-06 21:00 ` Bernd Edlinger
2017-04-07 6:54 ` Richard Biener
2017-04-07 13:37 ` Bernd Edlinger
2017-04-07 15:10 ` Richard Biener
2017-04-07 15:33 ` Bernd Edlinger
2017-04-07 20:22 ` Jason Merrill
2017-04-10 12:50 ` Richard Biener
2017-04-10 14:41 ` Jason Merrill
2017-04-10 15:31 ` Richard Biener [this message]
2017-04-10 16:35 ` Jason Merrill
2017-04-11 10:32 ` Richard Biener
2017-04-11 11:53 ` Richard Biener
2017-04-11 13:35 ` Richard Biener
2017-04-11 18:47 ` Jason Merrill
2017-04-10 21:40 ` Pedro Alves
2017-04-11 7:37 ` Richard Biener
2017-04-06 20:20 ` Bernd Edlinger
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