Hi Michal, > On 12 Jul 2022, at 14:35, Michal Jankovič via Gcc-patches > <gcc-patches@gcc.gnu.org> wrote: > > Currently, coroutine frames store all variables of a coroutine separately, > even if their lifetime does not overlap (they are in distinct scopes). This > patch implements overlapping distinct variable scopes in the coroutine frame, > by storing the frame fields in nested unions of structs. This lowers the size > of the frame for larger coroutines significantly, and makes them more usable > on systems with limited memory.
not a review (I will try to take a look at the weekend). but … this is one of the two main optimisations on my TODO - so cool for doing it. (the other related optimisation is to eliminate frame entries for scopes without any suspend points - which has the potential to save even more space for code with sparse use of co_xxxx) Iain > Bootstrapped and regression tested on x86_64-pc-linux-gnu; new test fails > before the patch and succeeds after with no regressions. > > PR c++/105989 > > gcc/cp/ChangeLog: > > * coroutines.cc (struct local_var_info): Add field_access_path. > (build_local_var_frame_access_expr): New. > (transform_local_var_uses): Use build_local_var_frame_access_expr. > (coro_make_frame_entry_id): New. > (coro_make_frame_entry): Delegate to coro_make_frame_entry_id. > (struct local_vars_frame_data): Add orig, field_access_path. > (register_local_var_uses): Generate new frame layout. Create access > paths to vars. > (morph_fn_to_coro): Set new fields in local_vars_frame_data. > > gcc/testsuite/ChangeLog: > > * g++.dg/coroutines/pr105989.C: New test. > > <pr105989.patch>
