tree.c (max_int_size_in_bytes): New function, inspired from code in function.c:assign_temp.

        * tree.c (max_int_size_in_bytes): New function, inspired from
        code in function.c:assign_temp.
        * tree.h (max_int_size_in_bytes): Declare.
        * function.c (assign_temp): Use it.
        * gimplify.c (create_tmp_var): Relax the assertions on the type
        properties, not mandating constant size any more.
        (force_constant_size): New static function.
        (gimple_add_tmp_var): Use it, forcing variable size to a
        constant upper bound if it is not constant on entry.

        * ada/misc.c (gnat_type_max_size): Look at TYPE_ADA_SIZE if we have
        not been able to get a constant upper bound from TYPE_SIZE_UNIT.

	* gnat.dg/varsize_temp.adb: New test.

From-SVN: r114938