Re: [RFC/PATCH] doc: volatile considered evil

[Jeremy Fitzhardinge <jeremy@goop.org>]

David Rientjes wrote:
> Now if all such output operands are to specify that the input operands 
> were "modified", 'volatile' is required to ensure the side-effects are 
> preserved or, otherwise, gcc is free optimize the entire asm construct 
> away since it appears to be unused.
>   

Yup.

>> Yeah, they're completely different.  They're not even analogous, really,
>> which was my point.  People confer more meaning to "asm volatile" than
>> it actually has, because of the analogy with volatile variables/types. 
>> They would have been better off with something like "asm static", which
>> isn't much more meaningful, but at least it doesn't mislead the reader
>> into thinking it has anything to do with the other volatile.
>>
>>     
>
> You're point about reordering "asm volatile" constructs differs depending 
> on -mvolatile-asm-stop or -mno-volatile-asm-stop, however.
>   

Erm, that seems to be ia64 specific, and I have no idea what adding a
"stop bit" implies.  Can you set even or odd parity too?

    J