Subj : Re: Memory visibility and the C compiler... ( a bit long )
To   : comp.programming.threads
From : Alexander Terekhov
Date : Thu Jan 13 2005 06:47 pm


SenderX wrote:
[...]
> > Reordering across "critical instructions" (inline asm
> > and/or external asm functions) is still possible (and is in fact
> > desirable as long as it doesn't break anything).
> 
> Are you talking about how the C compiler can reorder calls to external
> assembled functions? 

Yes. For example, an external assembled function with the effect of

  int f(...) {
    return 42;
  }

can be reordered in all the ways you can imagine. Oder?

>                      Or, how local variables might be moved in adverse

Variables and calls. Local and not so local.

> ways in the presence of multiple unrelated external function calls? 

Yes.

[...]
> I would greatly disapprove of a C compiler inspecting the instructions of
> my externally assembles routines! 

Why not? If it can do better and optimize them as well...

regards,
alexander.

.