re PR pch/53880 (compile time regression when generating precompiled headers for boost)
PR pch/53880
* gengtype.c (struct walk_type_data): Add have_this_obj field.
(walk_type): For functions that take a this_obj argument and
that process fields with a GTY((length)) argument, write the
test that write_types_local_process_field will write also at the
head of the loop, effectively unswitching the loop.
(write_func_for_structure, write_local_func_for_structure): Clear
have_this_obj before calling walk_type.
(write_local_func_for_structure): Set have_this_obj before walk_type.
(write_array): Set have_this_obj for output of local pointer walking
functions but not for marker functions.
(write_types_local_process_field): Assert have_this_obj is set.
* rtl.h (simplify_using_condition): Adjust prototype using bitmap
from coretypes.h.