[cfe-commits] [PATCH] Improved handling of 128-bit integer literals

[Stephen Canon]

On Nov 29, 2012, at 7:16 PM, Richard Smith <richard at metafoo.co.uk> wrote:

> Generally, we still need to handle Eli's observation that the C and C++ extended integer type rules require us to make intmax_t be __int128 if we're going to allow literals to be of type __int128. I'm inclined to say we should bite the bullet here, and treat __int128 as a proper extended integer type (and thus change intmax_t, preprocessor constant expressions, and so on). Any objections?

In the long run, I would very much like for intmax_t to be 128-bits where we can do so, but it's a *major* undertaking.  In particular, it requires considerable platform library support; off the top of my head:

• libc needs to be able to printf/scanf intmax_t via SCN*MAX / PRI*MAX, and needs to support strtoimax, etc.
• libc needs to support imaxdiv and imaxabs.

This will cause a decent amount of binary-compatibility headaches.  It's a goal worth aiming for, but it's a good ways off still.

- Steve