r191590 - Implements some of the more commonly used intrinsics in Intrin.h

[Timur Iskhodzhanov]

Please see the comment at
http://llvm.org/bugs/show_bug.cgi?id=13283#c5 for the details.

For some reason, the value of *_Addend at the end of the function is
wrong if we include <intrin.h>;
also, it fails to compile if we declare the function without including
the header.

2013/10/1 Warren Hunt <whunt at google.com>:
> I've tested them under a variety cases.  Are you concerned about the (-
> _Value) clause?
>
> -Warren
>
>
> On Mon, Sep 30, 2013 at 3:58 AM, Timur Iskhodzhanov <timurrrr at google.com>
> wrote:
>>
>> 2013/9/28 Warren Hunt <whunt at google.com>:
>> > +static __inline__
>> >  long __cdecl _InterlockedExchangeAdd(long volatile *_Addend, long
>> > _Value);
>> > ...
>> > +static __inline__ short __attribute__((__always_inline__, __nodebug__))
>> > +_InterlockedExchangeAdd16(short volatile *_Addend, short _Value) {
>> > +  return __atomic_add_fetch(_Addend, _Value, 0) - _Value;
>> > +}
>> > +static __inline__ long __attribute__((__always_inline__, __nodebug__))
>> > +_InterlockedExchangeAdd(long volatile *_Addend, long _Value) {
>> > +  return __atomic_add_fetch(_Addend, _Value, 0) - _Value;
>> > +}
>>
>> Are you sure this is a correct/complete implementation?
>> http://llvm.org/bugs/show_bug.cgi?id=13283#c5
>
>