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authorGabriel F. T. Gomes <gftg@linux.vnet.ibm.com>2017-08-22 16:34:42 -0300
committerGabriel F. T. Gomes <gftg@linux.vnet.ibm.com>2017-08-28 15:22:37 -0300
commit42496114ec0eb7d6d039d05d4262e109951c600c (patch)
tree02ff0c29ba5887cbd6fe2171015c339500574270 /math
parent56bc7f43603b5d28437496efb32df40997c62cb4 (diff)
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Provide a C++ version of iszero that does not use __MATH_TG (bug 21930)
When signaling nans are enabled (with -fsignaling-nans), the C++ version of iszero uses the fpclassify macro, which is defined with __MATH_TG. However, when support for float128 is available, __MATH_TG uses the builtin __builtin_types_compatible_p, which is only available in C mode. This patch refactors the C++ version of iszero so that it uses function overloading to select between the floating-point types, instead of relying on fpclassify and __MATH_TG. Tested for powerpc64le, s390x, x86_64, and with build-many-glibcs.py. [BZ #21930] * math/math.h [defined __cplusplus && defined __SUPPORT_SNAN__] (iszero): New C++ implementation that does not use fpclassify/__MATH_TG/__builtin_types_compatible_p, when signaling nans are enabled, since __builtin_types_compatible_p is a C-only feature. * math/test-math-iszero.cc: When __HAVE_DISTINCT_FLOAT128 is defined, include ieee754_float128.h for access to the union and member ieee854_float128.ieee. [__HAVE_DISTINCT_FLOAT128] (do_test): Call check_float128. [__HAVE_DISTINCT_FLOAT128] (check_float128): New function. * sysdeps/powerpc/powerpc64le/Makefile [subdir == math] (CXXFLAGS-test-math-iszero.cc): Add -mfloat128 to the build options of test-math-zero on powerpc64le.
Diffstat (limited to 'math')
-rw-r--r--math/math.h33
-rw-r--r--math/test-math-iszero.cc79
2 files changed, 108 insertions, 4 deletions
diff --git a/math/math.h b/math/math.h
index 9162bee50c..f3eb677a40 100644
--- a/math/math.h
+++ b/math/math.h
@@ -513,15 +513,40 @@ inline int issignaling (_Float128 __val) { return __issignalingf128 (__val); }
# endif
# else /* __cplusplus */
extern "C++" {
+# ifdef __SUPPORT_SNAN__
+inline int
+iszero (float __val)
+{
+ return __fpclassifyf (__val) == FP_ZERO;
+}
+inline int
+iszero (double __val)
+{
+ return __fpclassify (__val) == FP_ZERO;
+}
+inline int
+iszero (long double __val)
+{
+# ifdef __NO_LONG_DOUBLE_MATH
+ return __fpclassify (__val) == FP_ZERO;
+# else
+ return __fpclassifyl (__val) == FP_ZERO;
+# endif
+}
+# if __HAVE_DISTINCT_FLOAT128
+inline int
+iszero (_Float128 __val)
+{
+ return __fpclassifyf128 (__val) == FP_ZERO;
+}
+# endif
+# else
template <class __T> inline bool
iszero (__T __val)
{
-# ifdef __SUPPORT_SNAN__
- return fpclassify (__val) == FP_ZERO;
-# else
return __val == 0;
-# endif
}
+# endif
} /* extern C++ */
# endif /* __cplusplus */
#endif /* Use IEC_60559_BFP_EXT. */
diff --git a/math/test-math-iszero.cc b/math/test-math-iszero.cc
index 027e972654..5c07261626 100644
--- a/math/test-math-iszero.cc
+++ b/math/test-math-iszero.cc
@@ -22,6 +22,13 @@
#include <limits>
+/* Support for _Float128 in std::numeric_limits is limited.
+ Include ieee754_float128.h and use the bitfields in the union
+ ieee854_float128.ieee_nan to build corner-case inputs. */
+#if __HAVE_DISTINCT_FLOAT128
+# include <ieee754_float128.h>
+#endif
+
static bool errors;
static void
@@ -72,12 +79,84 @@ check_type ()
std::numeric_limits<T>::has_denorm == std::denorm_absent);
}
+#if __HAVE_DISTINCT_FLOAT128
+static void
+check_float128 ()
+{
+ ieee854_float128 q;
+
+ q.d = 0.0Q;
+ CHECK (iszero (q.d), 1);
+ q.d = -0.0Q;
+ CHECK (iszero (q.d), 1);
+ q.d = 1.0Q;
+ CHECK (iszero (q.d), 0);
+ q.d = -1.0Q;
+ CHECK (iszero (q.d), 0);
+
+ /* Normal min. */
+ q.ieee.negative = 0;
+ q.ieee.exponent = 0x0001;
+ q.ieee.mantissa0 = 0x0000;
+ q.ieee.mantissa1 = 0x00000000;
+ q.ieee.mantissa2 = 0x00000000;
+ q.ieee.mantissa3 = 0x00000000;
+ CHECK (iszero (q.d), 0);
+ q.ieee.negative = 1;
+ CHECK (iszero (q.d), 0);
+
+ /* Normal max. */
+ q.ieee.negative = 0;
+ q.ieee.exponent = 0x7FFE;
+ q.ieee.mantissa0 = 0xFFFF;
+ q.ieee.mantissa1 = 0xFFFFFFFF;
+ q.ieee.mantissa2 = 0xFFFFFFFF;
+ q.ieee.mantissa3 = 0xFFFFFFFF;
+ CHECK (iszero (q.d), 0);
+ q.ieee.negative = 1;
+ CHECK (iszero (q.d), 0);
+
+ /* Infinity. */
+ q.ieee.negative = 0;
+ q.ieee.exponent = 0x7FFF;
+ q.ieee.mantissa0 = 0x0000;
+ q.ieee.mantissa1 = 0x00000000;
+ q.ieee.mantissa2 = 0x00000000;
+ q.ieee.mantissa3 = 0x00000000;
+ CHECK (iszero (q.d), 0);
+
+ /* Quiet NaN. */
+ q.ieee_nan.quiet_nan = 1;
+ q.ieee_nan.mantissa0 = 0x0000;
+ CHECK (iszero (q.d), 0);
+
+ /* Signaling NaN. */
+ q.ieee_nan.quiet_nan = 0;
+ q.ieee_nan.mantissa0 = 0x4000;
+ CHECK (iszero (q.d), 0);
+
+ /* Denormal min. */
+ q.ieee.negative = 0;
+ q.ieee.exponent = 0x0000;
+ q.ieee.mantissa0 = 0x0000;
+ q.ieee.mantissa1 = 0x00000000;
+ q.ieee.mantissa2 = 0x00000000;
+ q.ieee.mantissa3 = 0x00000001;
+ CHECK (iszero (q.d), 0);
+ q.ieee.negative = 1;
+ CHECK (iszero (q.d), 0);
+}
+#endif
+
static int
do_test (void)
{
check_type<float> ();
check_type<double> ();
check_type<long double> ();
+#if __HAVE_DISTINCT_FLOAT128
+ check_float128 ();
+#endif
return errors;
}