Re: Volatile qualification on pointer and data

[David Brown <david at westcontrol dot com>]

On 21/09/2011 16:57, Paulo J. Matos wrote:
> On 21/09/11 15:21, David Brown wrote:
> > And since this
> > situation would not occur in real code (at least, not code that is
> > expected to do something useful other than test the compiler's code
> > generation), there is no harm in making sub-optimal object code.
>
> Actually the reason why I noticed this is because one of our engineers
> told that GCC stopped generating instructions for certain operations
> when he moved from GCC45 to GCC46. This code is real code.
>
> Cheers,

If you really have a "static const" object which you need to read as 
"volatile" for some reason, then I would seriously consider changing the 
code.  With "static const" you are telling the compiler it knows 
everything about the use of that object, and its value will never change 
- with "volatile" you are telling it that it's value might change behind 
the scenes.  Obviously you've only posted a code snippet and not your 
full code, but that sounds self-contradictory to me.  Somewhere along 
the line you are lying to the compiler - that's never a good idea when 
you want correct and optimal code.

David