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Re: Deprecating basic asm in a function - What now?


Hi,

On Tue, 21 Jun 2016, Andrew Haley wrote:

> > As said in the various threads about basic asms, all correctness 
> > problems can be solved by making GCC more conservative in handling 
> > them (or better said: not making it less conservative).
> 
> Well, yes.  That's exactly why we've agreed to change basic asms to make 
> them clobber memory, i.e. to make GCC more conservative.

Exactly.  But this thread is about something else, see subject.

> Well, maybe.  It's also fairly likely that many work by accident.  IMO 
> this is more of a statement of hope than any kind of reasonable 
> expectation.

Like yours, of course.

> > Then the compiler better won't change into less conservative handling 
> > of basic asms.
> 
> Repeat, repeat: the change being made is to make gcc MORE
> conservative.

This thread is about deprecating basic asms.  That's not more 
conservative, it's simply breaking backward compatibility for many users.

> > they work fine now.  Even if it weren't so it still would be silly if 
> > GCC simply could regard the former as the latter internally.
> 
> That's what we're doing.

Currently.  But not the proposed patch in this thread, and the general 
idea of deprecating the basic syntax.


Ciao,
Michael.


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