On 03.09.2013 22:25, Jason Merrill wrote:
On 09/03/2013 03:50 PM, Adam Butcher wrote:
Problem is that no RTL is set for the incoming parms in the
instantiation of the expansion. It ICEs in gimple_expand_cfg
because 'DECL_RTL_IF_SET
(var)' returns nullptr for the incoming parms resulting in a failed
assertion that
SA.partition_to_pseudo[i] is non-null.
Sounds like a problem with how _FUN's parameters are instantiated.
I'm not sure why it would be special.
Does using a function parameter pack in the lambda body work
currently? If so, how are the expanded parameters different?
Yes it does work. And I think (hope) I've cracked it;
make_pack_expansion needs to be called in the body of the thunk (i.e.
after start_preparsed_function).
If I butcher the implementation so that I rewrite any parameter packs
with their expansion prior to building the call in return statement, it
seems to work.
Certainly the following does what I expect it to, the trees look right
and, more importantly, it doesn't ICE!
auto g = [] <typename... P> (P...) -> float { return 3.f; };
float (*pg3) (double, double, double) = g;
return pg3(1,2,3);
I'll try to clean up what I've got then submit a rolled up patch.
Cheers,
Adam
