[cfe-dev] MS 128-bit literals don't always have the correct type

[Aaron Ballman]

On Sun, Sep 23, 2012 at 2:27 PM, Dmitri Gribenko <gribozavr at gmail.com> wrote:
> On Sun, Sep 23, 2012 at 9:24 PM, Cory Nelson <phrosty at gmail.com> wrote:
>> On Sun, Sep 23, 2012 at 11:20 AM, Dmitri Gribenko <gribozavr at gmail.com> wrote:
>>> Hello,
>>>
>>> Currently Clang chooses the type of MS 128-bit literals (<digits>i128,
>>> <digits>ui128) based on their value, as if there was no suffix, but
>>> also allows an extended 128-bit type.
>>>
>>> For example, on x86_64:
>>>
>>> 1i128 is equivalent to 1,
>>> 0x100000000i128 is same as 0x100000000L,
>>> and finally 0x10000000000000000i128 is indeed a 128-bit literal.
>>>
>>> I don't know if it is intended, but i128 is definitely treated
>>> differently way from other MS literal suffixes we accept (for example,
>>> i64 is essentially an alias for LL).
>>>
>>> I don't have Visual Studio so I can not check how it handles these literals.
>>
>> VC++ does not support 128-bit literals.
>
> I'm confused.  So why does Clang implement them?

There's an __int128 supplied by gcc
(http://gcc.gnu.org/onlinedocs/gcc/_005f_005fint128.html), but there's
not one for Visual Studio (at least not one officially documented).

~Aaron