rtl.texi (SUBREG_PROMOTED_UNSIGNED_P): Change definition to take ptr_extend into account as third type of extension.

        * doc/rtl.texi (SUBREG_PROMOTED_UNSIGNED_P): Change definition
        to take ptr_extend into account as third type of extension.
        (SUBREG_PROMOTED_UNSIGNED_SET): Definition of new macro to set bit
        fields used by SUBREG_PROMOTED_UNSIGNED_P.
        * rtl.h (SUBREG_PROMOTED_UNSIGNED_SET): New macro.
        (SUBREG_PROMOTED_UNSIGNED_P): Change to return -1 as well as 0 or 1.
        * calls.c (precompute_arguments): Use new macro.
        (expand_call): Ditto.
        * combine.c (nonzero_bits): Ditto.
        (record_promoted_value): Ditto.
        * expr.c (store_expr): Ditto.
        (expand_expr): Ditto.
        * function.c (assign_parms): Ditto.

From-SVN: r50174