PR/21391
	* testsuite/gcc.dg/20060410.c: New.
	* dwarf2out.c (struct die_struct): Add die_perennial_p field.
	(premark_used_types_helper): New.
	(premark_used_types): New.
	(gen_subprogram_die): Call premark_used_types.
	(prune_unused_types_walk): Do not prune perennial dies.
	* function.c (used_types_insert): New.
	* function.h (struct function): Add used_types_hash field.
	(used_types_insert): Add prototype.
	* Makefile.in (FUNCTION_H): Depend on HASHTAB_H.
	* c-parser.c (c_parser_cast_expression): Save casted types in used
	types hash table.

From-SVN: r112845