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Re: Volatile MEMs in statement expressions and functions inlined as trees


On 13-Dec-2001, Linus Torvalds <torvalds@transmeta.com> wrote:
> 
> For an expression like
> 
> 	extern volatile in p;
> 	p;
> 
> you would expect to see the assembly code to contain a dereference of "p",
> would you not?

No.  I wouldn't know what to expect.

> And that expected behaviour is indeed what gcc will do.

I just tried two other compilers (lcc 4.1 on Linux, and cc on SunOS 5.7)
and neither of them generated a dereference of "p".

It would be nicer IMHO if gcc warned that this code was non-portable.

I much prefer lcc's response:

x.c:4: warning: reference to `volatile int' elided
x.c:4: warning: expression with no effect elided

-- 
Fergus Henderson <fjh@cs.mu.oz.au>  |  "I have always known that the pursuit
The University of Melbourne         |  of excellence is a lethal habit"
WWW: <http://www.cs.mu.oz.au/~fjh>  |     -- the last words of T. S. Garp.


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