* defaults.h (CLZ_DEFINED_VALUE_AT_ZERO): New.
        (CTZ_DEFINED_VALUE_AT_ZERO): New.
        * doc/rtl.texi, doc/tm.texi: Document them.

        * combine.c (nonzero_bits) [CLZ, CTZ]: Handle the definedness
        of the value at zero properly.
        * fold-const.c (tree_expr_nonnegative_p): Likewise.
        * simplify-rtx.c (simplify_unary_operation): Likewise.

        * config/alpha/alpha.h (CLZ_DEFINED_VALUE_AT_ZERO): New.
        (CTZ_DEFINED_VALUE_AT_ZERO): New.

        * config/arm/arm.c (TARGET_INIT_BUILTINS): Remove.
        (TARGET_EXPAND_BUILTIN): Remove.
        (def_builtin, arm_init_builtins, arm_expand_builtin): Remove.
        * config/arm/arm.h (CLZ_DEFINED_VALUE_AT_ZERO): New.
        (enum arm_builtins): Remove.
        * config/arm/arm.md (UNSPEC_CLZ): Remove.
        (clzsi2): Rename from clz; use clz instead of unspec.
        (ctzsi2): New.
        * config/arm/arm-protos.h: Update.

From-SVN: r62453