Provide a C++ version of iseqsig (bug 22377)

In C++ mode, __MATH_TG cannot be used for defining iseqsig, because
__MATH_TG relies on __builtin_types_compatible_p, which is a C-only
builtin.  This is true when float128 is provided as an ABI-distinct type
from long double.

Moreover, the comparison macros from ISO C take two floating-point
arguments, which need not have the same type.  Choosing what underlying
function to call requires evaluating the formats of the arguments, then
selecting which is wider.  The macro __MATH_EVAL_FMT2 provides this
information, however, only the type of the macro expansion is relevant
(actually evaluating the expression would be incorrect).

This patch provides a C++ version of iseqsig, in which only the type of
__MATH_EVAL_FMT2 (__typeof or decltype) is used as a template parameter
for __iseqsig_type.  This function calls the appropriate underlying
function.

Tested for powerpc64le and x86_64.

	[BZ #22377]
	* math/Makefile [C++] (tests): Add test for iseqsig.
	* math/math.h [C++] (iseqsig): New implementation, which does
	not rely on __MATH_TG/__builtin_types_compatible_p.
	* math/test-math-iseqsig.cc: New file.
	* sysdeps/powerpc/powerpc64le/Makefile
	(CFLAGS-test-math-iseqsig.cc): New variable.
This commit is contained in:
Gabriel F. T. Gomes 2017-11-03 10:44:36 -02:00
parent 10e93d9687
commit c85e54ac6c
5 changed files with 198 additions and 5 deletions

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@ -1,3 +1,13 @@
2017-12-19 Gabriel F. T. Gomes <gabriel@inconstante.eti.br>
[BZ #22377]
* math/Makefile [C++] (tests): Add test for iseqsig.
* math/math.h [C++] (iseqsig): New implementation, which does
not rely on __MATH_TG/__builtin_types_compatible_p.
* math/test-math-iseqsig.cc: New file.
* sysdeps/powerpc/powerpc64le/Makefile
(CFLAGS-test-math-iseqsig.cc): New variable.
2017-12-19 Dmitry V. Levin <ldv@altlinux.org>
* elf/dl-load.c (is_trusted_path): Remove.

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@ -220,7 +220,7 @@ tests-static += atest-exp atest-sincos atest-exp2
ifneq (,$(CXX))
tests += test-math-isinff test-math-iszero test-math-issignaling \
test-math-iscanonical test-math-cxx11
test-math-iscanonical test-math-cxx11 test-math-iseqsig
endif
ifneq (no,$(PERL))

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@ -1182,8 +1182,76 @@ iszero (__T __val)
/* Return X == Y but raising "invalid" and setting errno if X or Y is
a NaN. */
# define iseqsig(x, y) \
__MATH_TG (__MATH_EVAL_FMT2 (x, y), __iseqsig, ((x), (y)))
# if !defined __cplusplus || (__cplusplus < 201103L && !defined __GNUC__)
# define iseqsig(x, y) \
__MATH_TG (__MATH_EVAL_FMT2 (x, y), __iseqsig, ((x), (y)))
# else
/* In C++ mode, __MATH_TG cannot be used, because it relies on
__builtin_types_compatible_p, which is a C-only builtin. Moreover,
the comparison macros from ISO C take two floating-point arguments,
which need not have the same type. Choosing what underlying function
to call requires evaluating the formats of the arguments, then
selecting which is wider. The macro __MATH_EVAL_FMT2 provides this
information, however, only the type of the macro expansion is
relevant (actually evaluating the expression would be incorrect).
Thus, the type is used as a template parameter for __iseqsig_type,
which calls the appropriate underlying function. */
extern "C++" {
template<typename> struct __iseqsig_type;
template<> struct __iseqsig_type<float>
{
static int __call (float __x, float __y) throw ()
{
return __iseqsigf (__x, __y);
}
};
template<> struct __iseqsig_type<double>
{
static int __call (double __x, double __y) throw ()
{
return __iseqsig (__x, __y);
}
};
template<> struct __iseqsig_type<long double>
{
static int __call (double __x, double __y) throw ()
{
# ifndef __NO_LONG_DOUBLE_MATH
return __iseqsigl (__x, __y);
# else
return __iseqsig (__x, __y);
# endif
}
};
# if __HAVE_DISTINCT_FLOAT128
template<> struct __iseqsig_type<_Float128>
{
static int __call (_Float128 __x, _Float128 __y) throw ()
{
return __iseqsigf128 (__x, __y);
}
};
# endif
template<typename _T1, typename _T2>
inline int
iseqsig (_T1 __x, _T2 __y) throw ()
{
# if __cplusplus >= 201103L
typedef decltype (__MATH_EVAL_FMT2 (__x, __y)) _T3;
# else
typedef __typeof (__MATH_EVAL_FMT2 (__x, __y)) _T3;
# endif
return __iseqsig_type<_T3>::__call (__x, __y);
}
} /* extern "C++" */
# endif /* __cplusplus */
#endif
__END_DECLS

111
math/test-math-iseqsig.cc Normal file
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@ -0,0 +1,111 @@
/* Test for the C++ implementation of iseqsig.
Copyright (C) 2017 Free Software Foundation, Inc.
This file is part of the GNU C Library.
The GNU C Library is free software; you can redistribute it and/or
modify it under the terms of the GNU Lesser General Public
License as published by the Free Software Foundation; either
version 2.1 of the License, or (at your option) any later version.
The GNU C Library is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
Lesser General Public License for more details.
You should have received a copy of the GNU Lesser General Public
License along with the GNU C Library; if not, see
<http://www.gnu.org/licenses/>. */
#define _GNU_SOURCE 1
#include <math.h>
#include <stdio.h>
#include <limits>
/* There is no NaN for _Float128 in std::numeric_limits.
Include ieee754_float128.h and use the bitfields in the union
ieee854_float128.ieee_nan to build a NaN. */
#if __HAVE_DISTINCT_FLOAT128
# include <ieee754_float128.h>
#endif
#include <support/check.h>
static void
check (int actual, int expected, const char *actual_expr, int line)
{
if (actual != expected)
{
support_record_failure ();
printf ("%s:%d: error: %s\n", __FILE__, line, actual_expr);
printf ("%s:%d: expected: %d\n", __FILE__, line, expected);
printf ("%s:%d: actual: %d\n", __FILE__, line, actual);
}
}
#define CHECK(actual, expected) \
check ((actual), (expected), #actual, __LINE__)
template <class T1, class T2>
static void
check_type ()
{
T1 t1 = 0;
T2 t2 = 0;
CHECK (iseqsig (t1, t2), 1);
t2 = 1;
CHECK (iseqsig (t1, t2), 0);
if (std::numeric_limits<T1>::has_quiet_NaN
&& std::numeric_limits<T2>::has_quiet_NaN)
{
CHECK (iseqsig (std::numeric_limits<T1>::quiet_NaN (), t2), 0);
CHECK (iseqsig (t1, std::numeric_limits<T2>::quiet_NaN ()), 0);
CHECK (iseqsig (std::numeric_limits<T1>::quiet_NaN (),
std::numeric_limits<T2>::quiet_NaN ()), 0);
}
}
#if __HAVE_DISTINCT_FLOAT128
static void
check_float128 ()
{
ieee854_float128 q1, q2, q3_nan;
q1.d = 0;
q2.d = 1;
q3_nan.ieee_nan.negative = 0;
q3_nan.ieee_nan.exponent = 0x7FFF;
q3_nan.ieee_nan.quiet_nan = 1;
q3_nan.ieee_nan.mantissa0 = 0x0000;
q3_nan.ieee_nan.mantissa1 = 0x00000000;
q3_nan.ieee_nan.mantissa2 = 0x00000000;
q3_nan.ieee_nan.mantissa3 = 0x00000000;
CHECK (iseqsig (q1.d, q1.d), 1);
CHECK (iseqsig (q1.d, q2.d), 0);
CHECK (iseqsig (q1.d, q3_nan.d), 0);
CHECK (iseqsig (q3_nan.d, q3_nan.d), 0);
}
#endif
static int
do_test (void)
{
check_type<float, float> ();
check_type<float, double> ();
check_type<float, long double> ();
check_type<double, float> ();
check_type<double, double> ();
check_type<double, long double> ();
check_type<long double, float> ();
check_type<long double, double> ();
check_type<long double, long double> ();
#if __HAVE_DISTINCT_FLOAT128
check_float128 ();
#endif
return 0;
}
#include <support/test-driver.c>

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@ -20,10 +20,14 @@ $(foreach suf,$(all-object-suffixes),$(objpfx)test-ifloat64x%$(suf)): CFLAGS +=
CFLAGS-libm-test-support-float128.c += -mfloat128
CFLAGS-libm-test-support-float64x.c += -mfloat128
CFLAGS-test-math-iscanonical.cc += -mfloat128
CFLAGS-test-math-iseqsig.cc += -mfloat128
CFLAGS-test-math-issignaling.cc += -mfloat128
CFLAGS-test-math-iszero.cc += -mfloat128
$(objpfx)test-float128% $(objpfx)test-ifloat128% \
$(objpfx)test-float64x% $(objpfx)test-ifloat64x% $(objpfx)test-math-iszero: \
$(foreach test, \
test-float128% test-ifloat128% test-float64x% test-ifloat64x% \
test-math-iscanonical test-math-iseqsig test-math-issignaling \
test-math-iszero, \
$(objpfx)$(test)): \
gnulib-tests += $(f128-loader-link)
endif