[cfe-dev] [RFC] Introduce overflow builtins

[Xi Wang]

On Mar 24, 2012, at 10:04 PM, Chris Lattner wrote:
> On Mar 22, 2012, at 6:12 AM, Xi Wang wrote:
>> Actually I used __builtin_saddo (__builtin_sadd_with_overflow is just too long).  Since this "saddo" looked a little bizarre to me, I changed it to __overflow_sadd.
> 
> I don't think a long name is a bad thing.  These builtins will be rarely used, it's just that they are important when they do get used.
> 
>> I was also wondering which would be better, __overflow_*(T*, T, T) or __overflow_*(T, T, T*).
> 
> I don't have a preference one way or the other.  Are there any precedents?

Okay.  Let's try

	__builtin_*_with_overflow(T, T, T*);

to keep the names consistent with the LLVM counterparts.  Also it's probably more intuitive to let the output parameter come after the inputs.

Does this sound good?

- xi