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[Bug c/65455] typeof _Atomic fails
- From: "joseph at codesourcery dot com" <gcc-bugzilla at gcc dot gnu dot org>
- To: gcc-bugs at gcc dot gnu dot org
- Date: Thu, 19 Mar 2015 00:29:47 +0000
- Subject: [Bug c/65455] typeof _Atomic fails
- Auto-submitted: auto-generated
- References: <bug-65455-4 at http dot gcc dot gnu dot org/bugzilla/>
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=65455
--- Comment #10 from joseph at codesourcery dot com <joseph at codesourcery dot com> ---
On Wed, 18 Mar 2015, jens.gustedt at inria dot fr wrote:
> (Perhaps gcc interprets _Generic as you say, but even the standard committee
> doesn't agree on that interpretation, and other compiler implementors don't
> agree either. Nothing in the standard says that it is an rvalue, nor that it
> has to undergo any conversion. Conversion for non-evaluated expressions simply
> doesn't exist in the standard. The standard explicitly asks for compatible type
> of the expression itself, it says nothing about unqualified type.)
There isn't yet a conclusion to DR#423, but the committee discussion in
N1892 says 'Specifically, the controlling expression of a generic
selection "was very carefully not added" to the list of cases where lvalue
conversion is not done.' (i.e. that conversion happens to all expressions
unless excluded from happening). There is no indication of a committee
direction contradicting the approach I chose for GCC (even if the
committee isn't quite sure of how to handle atomics there, and has
suggested making qualifiers on function return types not part of the
type).