Re: Some extra decorations

["Peter Dimov" <pdimov at mmltd dot net>]

Jan Hubicka:

> There are also few annotations that I would like to add to functions
> declared in headers where GCC don't know if they are finite so it is not
> sure it can remove call to them even if it can prove there are no side
> effects otherwise.

Hi,

You may be interested in 6.5p5 of the latest standard draft (N2857) which 
states:

"A loop that, outside of the for-init-statement in the case of a for 
statement,
- makes no calls to library I/O functions, and
- does not access or modify volatile objects, and
- performs no synchronization operations (1.10) or atomic operations (Clause 
29)
may be assumed by the implementation to terminate. [ Note: This is intended 
to allow compiler transformations, such as removal of empty loops, even when 
termination cannot be proven. -end note ]"

This new rule has been introduced by the memory model changes.