cselib+expr+bitmap: Change return type of predicate functions from int to bool
gcc/ChangeLog:
* cselib.h (rtx_equal_for_cselib_1):
Change return type from int to bool.
(references_value_p): Ditto.
(rtx_equal_for_cselib_p): Ditto.
* expr.h (can_store_by_pieces): Ditto.
(try_casesi): Ditto.
(try_tablejump): Ditto.
(safe_from_p): Ditto.
* sbitmap.h (bitmap_equal_p): Ditto.
* cselib.cc (references_value_p): Change return type
from int to void and adjust function body accordingly.
(rtx_equal_for_cselib_1): Ditto.
* expr.cc (is_aligning_offset): Ditto.
(can_store_by_pieces): Ditto.
(mostly_zeros_p): Ditto.
(all_zeros_p): Ditto.
(safe_from_p): Ditto.
(is_aligning_offset): Ditto.
(try_casesi): Ditto.
(try_tablejump): Ditto.
(store_constructor): Change "need_to_clear" and
"const_bounds_p" variables to bool.
* sbitmap.cc (bitmap_equal_p): Change return type from int to bool.