[cfe-commits] [PATCH] atomic operation builtins, part 1

[Jeffrey Yasskin]

On Wed, Oct 12, 2011 at 6:31 AM, Andrew MacLeod <amacleod at redhat.com> wrote:
> - language atomic types up to 16 bytes should be padded to an appropriate
> size, and aligned properly.
> - if memory matching one of the 5 'optimized' sizes isn't aligned properly,
> results are undefined.
> - if the size does not match one of the 5 specific routines, then the
> library generic ABI can handle it.  There's no alignment guarantees, so I
> presume it would end up being a locked implementation using hash tables and
> addresses or something.

The ABI library needs to demand alignment guarantees, or have them
passed in, or it won't be able to support larger lock-free sizes on
new architectures.