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

Jeremy Fitzhardinge
2007-05-08T22:29:35Z

David Rientjes wrote:
> It is analogous with a sequence point for ia64. But, as you mentioned, it
> is ia64 specific so your comment about "asm volatile" constructs not being
> reordered is always appropriate outside of ia64 specific code but may not
> apply to ia64 if we ever compiled with -mvolatile-asm-stop. If we do not
> compile with that option, the behavior is unspecified. I don't think
> we'll be adding -mvolatile-asm-stop support any time soon so your warning
> certainly is appropriate for all code at this time.
>

Sounds like it's referring to micro-architectural reordering, which is
distinct from compiler reordering. In other words, even if you
specified "-mvolatile-asm-stop" I would assume that the compiler could
still reorder the asm statements. Am I right, or should I read more
into the manual description than it actually says?

J