[cfe-dev] [LLVMdev] pinging 18097: atomic<> of trivially copyable class is rejected

[Hal Finkel]

Tim,

I'm moving this to cfe-dev (this is a frontend issue). When pinging an issue, it helps to provide a brief synopsis of the problem...

Looking at this briefly, the question seems to center on whether clang should support converting from T to _Atomic(T) for non-POD (but trivially copyable) types. Currently it does not, but the libc++ implementation of atomic<T> is based on _Atomic(T) and inherits this restriction, rendering it non-conforming. Howard had created a libc++ patch to change the implementation of atomic<T> so that it was not directly based on _Atomic(T), but noted that a clang change could also fix the issue. Looking at Howard's patch, I can understand his hesitation (it certainly makes the implementation more complicated).

 -Hal

----- Original Message -----
> From: "Tim Blechmann" <tim at klingt.org>
> To: llvmdev at cs.uiuc.edu
> Sent: Sunday, July 13, 2014 5:32:01 AM
> Subject: *****SPAM*****[LLVMdev] pinging 18097: atomic<> of trivially copyable class is	rejected
> 
> hi all,
> 
> bug 18097 has already been discussed on this list more than a year
> ago,
> and it is open with a patch attached since last autumn ... despite
> being
> tagged as release blocker. is there any estimation when this issue
> will
> be fixed?
> 
> tia,
> tim
> 
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> 

-- 
Hal Finkel
Assistant Computational Scientist
Leadership Computing Facility
Argonne National Laboratory