From: Jason Merrill <jason@redhat.com>
To: Nathan Sidwell <nathan@acm.org>, GCC Patches <gcc-patches@gcc.gnu.org>
Subject: Re: [C++/66270] another may_alias crash
Date: Wed, 27 May 2015 16:36:00 -0000 [thread overview]
Message-ID: <5565EEC5.9090703@redhat.com> (raw)
In-Reply-To: <5564C2DD.2030700@acm.org>
On 05/26/2015 03:00 PM, Nathan Sidwell wrote:
> Ok, so IIUC a canonical pointer to a may_alias type should have TRCAA
> but a canonical can_alias_all pointer to a non-may_alias type should not
> have TRCAA? (i.e. one where CAN_ALIAS_ALL was passed true). Or are you
> saying that no canonical pointers should have TRCAA?
The former: A canonical pointer should have TRCAA if and only if the
canonical referent is may_alias.
>> Hmm, are you seeing a case where TYPE_CANONICAL (to_type) has the
>> may_alias attribute?
>
> Yes. This occurs when the newly created TRCAA pointer is to a
> self-canonical type.
Hmm, seems like that's another problem with your testcase: the canonical
variant of __m256 should not have may_alias. But the canonical variant
of a class or enum type could still have may_alias, so we still need to
handle that case.
The patch is OK.
Jason
next prev parent reply other threads:[~2015-05-27 16:20 UTC|newest]
Thread overview: 6+ messages / expand[flat|nested] mbox.gz Atom feed top
2015-05-25 21:09 Nathan Sidwell
2015-05-26 7:52 ` Jason Merrill
2015-05-26 19:18 ` Nathan Sidwell
2015-05-27 12:42 ` Nathan Sidwell
2015-05-27 16:36 ` Jason Merrill [this message]
2015-05-27 21:26 ` Nathan Sidwell
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