* builtin-types.def (BT_FN_VOID_PTR_VAR): New.
* builtins.def (BUILT_IN_PREFETCH): Change arguments.
* builtins.c (expand_builtin_prefetch): Two arguments are now optional,
with defaults for read prefetch with high degree of locality.
* doc/extend.texi (__builtin_prefetch): Update documentation.
* doc/md.texi (prefetch): Add documentation.
From-SVN: r47741
