On Wed, Aug 1, 2018 at 7:07 PM, Jakub Jelinek <ja...@redhat.com> wrote: > On Wed, Aug 01, 2018 at 12:35:09AM +1000, Jason Merrill wrote: >> On Mon, Jul 23, 2018 at 8:50 PM, Richard Biener >> <richard.guent...@gmail.com> wrote: >> > On Mon, Jul 23, 2018 at 12:28 PM Jakub Jelinek <ja...@redhat.com> wrote: >> >> >> >> On Mon, Jul 23, 2018 at 12:17:42PM +0200, Richard Biener wrote: >> >> > > Bootstrapped/regtested on x86_64-linux. >> >> > >> >> > Thanks for working on this. I wonder if we can completely hide this >> >> > from the middle-end, without requiring defining of c_dialect_cxx. >> >> > There is the BUILT_IN_FRONTEND class so you could somewhere >> >> > manually inject a decl in that class for C++? >> >> >> >> But then I couldn't handle folding of the builtin in the middle-end to >> >> false, >> >> which is what I need (because in the FE it needs to be either folded to >> >> true, or its folding deferred until later). >> >> Or maybe in the C++ gimplification langhook? >> > >> > Yes, I was thinking the C++ langhook or its fully_fold routine. >> >> fully_fold is too soon (until constexpr evaluation uses the >> pre-genericize form), but the gimplification hook should work. >> >> >> Seems we have a single BUILT_IN_FRONTEND builtin in the whole compiler, >> >> __integer_pack, but it doesn't act as a normal builtin, given it is a >> >> templatish magic. >> > >> > Yeah, I think at some point we considered removing BUILT_IN_FRONTEND ... >> > >> > Nowadays internal-use builtins can easily be internal-functions but of >> > couse >> > this one will eventually be used from libstdc++. >> >> Immediately, I'd think. > > Here is an updated patch that uses BUILT_IN_FRONTEND for this rather than > BUILT_IN_NORMAL builtin. > > Bootstrapped/regtested on x86_64-linux and i686-linux. > > 2018-08-01 Jakub Jelinek <ja...@redhat.com> > > P0595R1 - is_constant_evaluated > cp/ > * cp-tree.h (enum cp_built_in_function): New. > (maybe_constant_init): Add const_evaluated argument.
We should document that this new parameter (here and in cxx_eval_outermost_constant_expr) means "required to be constant-evaluated" as per P0595 even though allow_non_constant is true. And the parameter names should make its magical nature more obvious; perhaps "pretend_const_required". OK with those changes. Jason
