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Re: C++: Letting compiler know asm block can call function that can throw?
On Thu, Mar 29, 2012 at 8:34 PM, Richard Henderson <rth@redhat.com> wrote:
> On 03/29/2012 01:16 PM, Jan Hubicka wrote:
>>> Of course, there's still the problem of getting the unwind data correct at
>>> the point of the asm. ?I commented about that in the PR you filed.
>>
>> I think i386 still has the problem that it is small register class target and if you
>> set rdi/rax and friends as hard registers, you risk reload failures.
>
> True, and if this were i386 code I would certainly recommend using the [acd]
> constraints instead (for suitible regparm signature). ?But this is explicitly
> x86_64 code and the compiler has 8 registers otherwise available.
>
>> Do we prevent code motion of hard registers sets i.e. at GIMPLE level?
Yes we do (modulo bugs).
> I don't know for positive, but I'd certainly consider it a bug if we don't.
> There are plenty of targets which have no alternative but to use this style
> of programming for inline syscalls.
>
>
> r~