[cfe-dev] C++ and volatile lvalue-to-rvalue
abramo.bagnara at gmail.com
Thu Oct 13 09:20:47 PDT 2011
Il 13/10/2011 17:33, Christopher Jefferson ha scritto:
> On 13 Oct 2011, at 12:43, Abramo Bagnara wrote:
>> I want to put this gcc bug report to clang developer attention.
>> The gcc developers believe that according to the standard
>> volatile int v;
>> x = v = 3;
>> does not imply necessarily a read from v.
> If you want to argue that this should both write to, and read from v, then I think you fall foul of lack of a sequence point, so the behaviour is undefined anyway.
We don't have a sequence point, but we have a partial ordering mandated
by the standard: the write should be done before the read (see 5.17p1).
Or you meant another source of undefined behaviour?
Note also that recent C++ standard no longer refers former "sequence
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