gcc/
        * builtin-types.def (BT_FN_FLOAT_CONST_STRING): New.
        (BT_FN_DOUBLE_CONST_STRING, BT_FN_LONG_DOUBLE_CONST_STRING): New.
        * builtins.def (__builtin_nan, __builtin_nanf, __builtin_nanl): New.
        (__builtin_nans, __builtin_nansf, __builtin_nansl): New.
        * builtins.c (fold_builtin_nan): New.
        (fold_builtin): Call it.
        * real.c (real_nan): Parse a non-empty string.
        (round_for_format): Fix NaN significand truncation.
        * real.h (real_nan): Return bool.
        * doc/extend.texi: Document new builtins.

libstdc++/
        * include/std/std_limits.h (__glibcpp_f32_QNaN_bytes,
        __glibcpp_f32_has_QNaN, __glibcpp_f32_SNaN_bytes,
        __glibcpp_f32_has_SNaN, __glibcpp_f64_QNaN_bytes,
        __glibcpp_f64_has_QNaN, __glibcpp_f64_SNaN_bytes,
        __glibcpp_f64_has_SNaN, __glibcpp_f80_QNaN_bytes,
        __glibcpp_f80_has_QNaN, __glibcpp_f80_SNaN_bytes,
        __glibcpp_f80_has_SNaN, __glibcpp_f96_QNaN_bytes,
        __glibcpp_f96_has_QNaN, __glibcpp_f96_SNaN_bytes,
        __glibcpp_f96_has_SNaN, __glibcpp_f128_QNaN_bytes,
        __glibcpp_f128_has_QNaN, __glibcpp_f128_SNaN_bytes,
        __glibcpp_f128_has_SNaN, __glibcpp_float_QNaN_bytes,
        __glibcpp_float_has_QNaN, __glibcpp_float_SNaN_bytes,
        __glibcpp_float_has_SNaN, __glibcpp_double_QNaN_bytes,
        __glibcpp_double_has_QNaN, __glibcpp_double_SNaN_bytes,
        __glibcpp_double_has_SNaN, __glibcpp_long_double_QNaN_bytes,
        __glibcpp_long_double_has_QNaN, __glibcpp_long_double_SNaN_bytes,
        __glibcpp_long_double_has_SNaN): Remove.
        (__glibcpp_f128_is_iec559): True if IEEE.
        (__glibcpp_float_QNaN, __glibcpp_float_SNaN): Remove.
        (__glibcpp_double_QNaN, __glibcpp_double_SNaN): Remove.
        (__glibcpp_long_double_QNaN, __glibcpp_long_double_SNaN): Remove.
        (std::numeric_limits<float>::has_quiet_NaN): Use __builtin_nanf.
        (std::numeric_limits<float>::has_signaling_NaN): Mirror has_quiet_NaN.
        (std::numeric_limits<float>::quiet_NaN): Use __builtin_nanf.
        (std::numeric_limits<float>::signaling_NaN): Use __builtin_nansf.
        (std::numeric_limits<double>): Similarly.
        (std::numeric_limits<long double>): Similarly.
        * src/limits.cc (__glibcpp_float_QNaN, __glibcpp_float_SNaN): Remove.
        (__glibcpp_double_QNaN, __glibcpp_double_SNaN): Remove.
        (__glibcpp_long_double_QNaN, __glibcpp_long_double_SNaN): Remove.

        * testsuite/18_support/numeric_limits.cc (test_infinity): New.
        (test_denorm_min, test_qnan, test_is_iec559): New.

From-SVN: r57221