gdb/

gdb/
	Add gdb.Value.is_optimized_out attribute.
	* python/python-value.c (valpy_get_is_optimized_out): New
	function.
	(value_object_getset): New variable.
	(value_object_type): Initialize tp_getset element.

gdb/doc/
	* gdb.texinfo (Values From Inferior): Document is_optimized_out
	attribute.

gdb/testsuite/
	* gdb.python/python-value.exp (test_value_in_inferior): Test
	gdb.Value.is_optimized_out attribute.