From: Richard Biener <richard.guenther@gmail.com>
To: Jason Merrill <jason@redhat.com>
Cc: gcc-patches List <gcc-patches@gcc.gnu.org>
Subject: Re: RFA (tree.c): PATCH for may_alias vs. TYPE_CANONICAL, related to c++/50800
Date: Fri, 24 Apr 2015 08:13:00 -0000 [thread overview]
Message-ID: <CAFiYyc294Crcd2vv=sLzbdNsmpiBn6gOPSpJEsd6018oF+aOmQ@mail.gmail.com> (raw)
In-Reply-To: <55391495.8040103@redhat.com>
On Thu, Apr 23, 2015 at 5:49 PM, Jason Merrill <jason@redhat.com> wrote:
> In general, TYPE_CANONICAL of a type strips all attributes. An exception to
> this seems to be that TYPE_REF_CAN_ALIAS_ALL remains set on the
> TYPE_CANONICAL of a pointer/reference type even though its TREE_TYPE no
> longer has the may_alias attribute, and is inconsistent with
> "affects_type_identity" being false for may_alias. This seems to have been
> a mistake in the patch that first introduced TYPE_CANONICAL, rather than a
> deliberate choice.
>
> I'm also planning to fix 50800 in the front end, but this patch still seems
> like an improvement.
>
> Tested x86-64-pc-linux-gnu, OK for trunk?
Looks good to me. We eventually were confused by alias.c get_alias_set
dropping to TYPE_CANONICAL (TYPE_MAIN_VARIANT (T)) before determining
the alias set of a type T. But of course ref-all is only relevant for
the alias-set
of type *T.
Richard.
prev parent reply other threads:[~2015-04-24 8:13 UTC|newest]
Thread overview: 2+ messages / expand[flat|nested] mbox.gz Atom feed top
2015-04-23 15:49 Jason Merrill
2015-04-24 8:13 ` Richard Biener [this message]
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='CAFiYyc294Crcd2vv=sLzbdNsmpiBn6gOPSpJEsd6018oF+aOmQ@mail.gmail.com' \
--to=richard.guenther@gmail.com \
--cc=gcc-patches@gcc.gnu.org \
--cc=jason@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).