Re: Implement numeric_limits<__float128>.

2019-05-10 Thread Marc Glisse 

On Fri, 10 May 2019, Ed Smith-Rowland via libstdc++ wrote:

I know people are mostly looking at release branch work but I'd like to post 
this.  Other projects like mppp and boost use our __float128 with C++.  I use 
it for specfun testing and various other projects. I'd like to offer a series 
of patches to enable this support straight from libstdc++.  This is the first 
patch. Next will be  and then  a bit later.


It's pretty straightforward but others might have tips on configuration (and 
anything else ;-)).  Built and tested of x86_64-linux.


+#  define FLT128_MAX 1.18973149535723176508575932662800702e4932Q
+#  define FLT128_MIN 3.36210314311209350626267781732175260e-4932Q
etc

do such names really belong in ?

I see that the preprocessor has macros
#define __FLT128_MAX__ 1.18973149535723176508575932662800702e+4932F128
#define __FLT128_MIN__ 3.36210314311209350626267781732175260e-4932F128

for type _Float128 but the C++ compiler does not know that type or 
operator""F128. It seems broken that the compiler defines the macro for 
something it does not support. Having FLT128_MIN and __FLT128_MIN__ refer 
to different things seems like a bad idea. If you define 
__STDC_WANT_IEC_60559_TYPES_EXT__ and include  you already get 
FLT128_MIN as _Float128 and if you include  you already get 
FLT128_MIN as __float128 (and if you do both in this order you get a 
redefinition warning with -Wsystem-headers).


--
Marc Glisse

Implement numeric_limits<__float128>.

2019-05-10 Thread Ed Smith-Rowland via gcc-patches 

Greetings,

I know people are mostly looking at release branch work but I'd like to 
post this.  Other projects like mppp and boost use our __float128 with 
C++.  I use it for specfun testing and various other projects. I'd like 
to offer a series of patches to enable this support straight from 
libstdc++.  This is the first patch. Next will be  and then 
 a bit later.


It's pretty straightforward but others might have tips on configuration 
(and anything else ;-)).  Built and tested of x86_64-linux.


Ok?

Ed


2019-05-11  Ed Smith-Rowland  <3dw...@verizon.net>

    Implement numeric_limits<__float128>.
* include/std/limits: Copy limit macros from quadmath.h;
(__glibcxx_float128_has_denorm_loss, __glibcxx_float128_traps,
__glibcxx_float128_tinyness_before): New macros (set to false);
(numeric_limits<__float128>): New specialization.
* : Add __float128 test guarded by _GLIBCXX_USE_FLOAT128.
* : testsuite/18_support/numeric_limits/denorm_min.cc: Add __float128
test guarded by _GLIBCXX_USE_FLOAT128.
* : testsuite/18_support/numeric_limits/dr559.cc: Same.
* : testsuite/18_support/numeric_limits/epsilon.cc: Same.
* : testsuite/18_support/numeric_limits/infinity.cc: Same.
* : testsuite/18_support/numeric_limits/is_iec559.cc: Same.
* : testsuite/18_support/numeric_limits/lowest.cc: Same.
* : testsuite/18_support/numeric_limits/max_digits10.cc: Same.
* : testsuite/18_support/numeric_limits/min_max.cc: Same.
* : testsuite/18_support/numeric_limits/quiet_NaN.cc: Same.

Index: include/std/limits
===
--- include/std/limits  (revision 271076)
+++ include/std/limits  (working copy)
@@ -41,6 +41,19 @@
 
 #include 
 
+#if defined(_GLIBCXX_USE_FLOAT128) && !defined(__STRICT_ANSI__)
+#  define FLT128_MAX 1.18973149535723176508575932662800702e4932Q
+#  define FLT128_MIN 3.36210314311209350626267781732175260e-4932Q
+#  define FLT128_EPSILON 1.92592994438723585305597794258492732e-34Q
+#  define FLT128_DENORM_MIN 6.475175119438025110924438958227646552e-4966Q
+#  define FLT128_MANT_DIG 113
+#  define FLT128_MIN_EXP (-16381)
+#  define FLT128_MAX_EXP 16384
+#  define FLT128_DIG 33
+#  define FLT128_MIN_10_EXP (-4931)
+#  define FLT128_MAX_10_EXP 4932
+#endif
+
 //
 // The numeric_limits<> traits document implementation-defined aspects
 // of fundamental arithmetic data types (integers and floating points).
@@ -123,6 +136,24 @@
 #  define __glibcxx_long_double_tinyness_before false
 #endif
 
+#if defined(_GLIBCXX_USE_FLOAT128) && !defined(__STRICT_ANSI__)
+
+// __float128
+
+// Default values.  Should be overridden in configuration files if necessary.
+
+#  ifndef __glibcxx_float128_has_denorm_loss
+#define __glibcxx_float128_has_denorm_loss false
+#  endif
+#  ifndef __glibcxx_float128_traps
+#define __glibcxx_float128_traps false
+#  endif
+#  ifndef __glibcxx_float128_tinyness_before
+#define __glibcxx_float128_tinyness_before false
+#  endif
+
+#  endif // _GLIBCXX_USE_FLOAT128
+
 // You should not need to define any macros below this point.
 
 #define __glibcxx_signed_b(T,B)((T)(-1) < 0)
@@ -1880,6 +1911,85 @@
 #undef __glibcxx_long_double_traps
 #undef __glibcxx_long_double_tinyness_before
 
+#if defined(_GLIBCXX_USE_FLOAT128) && !defined(__STRICT_ANSI__)
+
+  /// numeric_limits<__float128> specialization.
+  template<>
+struct numeric_limits<__float128>
+{
+  static _GLIBCXX_USE_CONSTEXPR bool is_specialized = true;
+
+  static _GLIBCXX_CONSTEXPR __float128
+  min() _GLIBCXX_USE_NOEXCEPT { return FLT128_MIN; }
+
+  static _GLIBCXX_CONSTEXPR __float128
+  max() _GLIBCXX_USE_NOEXCEPT { return FLT128_MAX; }
+
+#if __cplusplus >= 201103L
+  static _GLIBCXX_CONSTEXPR __float128
+  lowest() _GLIBCXX_USE_NOEXCEPT { return -FLT128_MAX; }
+#endif
+
+  static _GLIBCXX_USE_CONSTEXPR int digits = FLT128_MANT_DIG;
+  static _GLIBCXX_USE_CONSTEXPR int digits10 = FLT128_DIG;
+#if __cplusplus >= 201103L
+  static _GLIBCXX_USE_CONSTEXPR int max_digits10
+= __glibcxx_max_digits10 (FLT128_MANT_DIG);
+#endif
+  static _GLIBCXX_USE_CONSTEXPR bool is_signed = true;
+  static _GLIBCXX_USE_CONSTEXPR bool is_integer = false;
+  static _GLIBCXX_USE_CONSTEXPR bool is_exact = false;
+  static _GLIBCXX_USE_CONSTEXPR int radix = __FLT_RADIX__;
+
+  static _GLIBCXX_CONSTEXPR __float128
+  epsilon() _GLIBCXX_USE_NOEXCEPT { return FLT128_EPSILON; }
+
+  static _GLIBCXX_CONSTEXPR __float128
+  round_error() _GLIBCXX_USE_NOEXCEPT { return 0.5Q; }
+
+  static _GLIBCXX_USE_CONSTEXPR int min_exponent = FLT128_MIN_EXP;
+  static _GLIBCXX_USE_CONSTEXPR int min_exponent10 = FLT128_MIN_10_EXP;
+  static _GLIBCXX_USE_CONSTEXPR int max_exponent = FLT128_MAX_EXP;
+  static _GL