New early __builtin_unreachable processing.
in VRP passes before __builtin_unreachable MUST be removed, only remove it
if all exports affected by the unreachable can have global values updated, and
do not involve loads from memory.
PR tree-optimization/110080
PR tree-optimization/110249
gcc/
* tree-vrp.cc (remove_unreachable::final_p): New.
(remove_unreachable::maybe_register): Rename from
maybe_register_block and call early or final routine.
(fully_replaceable): New.
(remove_unreachable::handle_early): New.
(remove_unreachable::remove_and_update_globals): Remove
non-final processing.
(rvrp_folder::rvrp_folder): Add final flag to constructor.
(rvrp_folder::post_fold_bb): Remove unreachable registration.
(rvrp_folder::pre_fold_stmt): Move unreachable processing to here.
(execute_ranger_vrp): Adjust some call parameters.
gcc/testsuite/
* g++.dg/pr110249.C: New.
* gcc.dg/pr110080.c: New.
* gcc.dg/pr93917.c: Adjust.