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Re: x86_64: Should the -mavx* options affected __alignof__ (max_align_t)?
- From: Florian Weimer <fweimer at redhat dot com>
- To: Joseph Myers <joseph at codesourcery dot com>
- Cc: GCC <gcc at gcc dot gnu dot org>
- Date: Thu, 02 Apr 2015 10:26:32 +0200
- Subject: Re: x86_64: Should the -mavx* options affected __alignof__ (max_align_t)?
- Authentication-results: sourceware.org; auth=none
- References: <55105B5B dot 50107 at redhat dot com> <alpine dot DEB dot 2 dot 10 dot 1503231831300 dot 14930 at digraph dot polyomino dot org dot uk> <55105E53 dot 8020002 at redhat dot com>
On 03/23/2015 07:41 PM, Florian Weimer wrote:
> Ah, I should have looked at what max_align_t actually meant. With these
> semantics, the name is a bit confusing. I agree that requiring 64 byte
> alignment from malloc does not make much sense. Thanks.
Follow-up question: Can malloc return a pointer which is not aligned to
_Alignof (max_align_t)?
This happens with most mallocs on x86_64 for sizes of 8 or less, for
which these mallocs only provide an alignment of 8.
DR445 does not seem to have reached consensus on that point.
--
Florian Weimer / Red Hat Product Security