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Re: "+m" constraints bogus?
> Hi,
>
> On Wed, 25 Jul 2007, Jan Hubicka wrote:
>
> > Yep, I am aware of those problems (reload dying in horrible death as
> > soon as something didn't ended up matching). I was somewhat confused
> > thinking that gimplifier gimplifies into the pair as in my testcase
> > above, not the "=m" "m" pair.
> >
> > I guess we are safe now support them so I would just update the manual
> > with a simple testcase so we know gimplifier does not break and we won't
> > re-start emitting the warning?
>
> Seems sensible, yes.
Just because it probably wasn't mentioned explicitely - the gimplifier
approach is a bit weak in a sense that there is theoretically nothing
explicitly keeping memory address of input and output operand the same
through the compilation and in future we might invent optimizer
modifying memory operands in a way that this breaks, but it seems like
sane invariant to maintain for ASM operands...
Honza
>
>
> Ciao,
> Michael.