tree-object-size: Clean up unknown propagation
Narrow down scope of the unknowns bitmap so that it is only accessible
within the reexamination process. This also removes any role of unknown
propagation from object_sizes_set, thus simplifying that code path a
bit.
gcc/ChangeLog:
* tree-object-size.cc (object_size_info): Remove UNKNOWNS.
Drop all references to it.
(object_sizes_set): Move unknowns propagation code to...
(gimplify_size_expressions): ... here. Also free reexamine
bitmap.
(propagate_unknowns): New parameter UNKNOWNS. Update callers.
Signed-off-by: Siddhesh Poyarekar <siddhesh@gotplt.org>