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Remove use of std::abs in experimental::{gcd,lcm}

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PR libstdc++/77801
	* include/experimental/numeric: Include <numeric>.
	(__abs): Define.
	(gcd, lcm): Use __abs instead of std::abs.
	* testsuite/experimental/numeric/77801.cc: New test.
	* testsuite/experimental/numeric/gcd.cc: Test unsigned inputs.
	* testsuite/experimental/numeric/lcm.cc: Likewise.

From-SVN: r240656
This commit is contained in:
Jonathan Wakely 2016-09-30 14:43:37 +01:00 • committed by Jonathan Wakely
parent e70bbc6f1f
commit 9e28a77462
5 changed files with 57 additions and 4 deletions
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10
libstdc++-v3/ChangeLog
View file

@ -1,3 +1,13 @@
2016-09-30 Jonathan Wakely <jwakely@redhat.com>
PR libstdc++/77801
* include/experimental/numeric: Include <numeric>.
(__abs): Define.
(gcd, lcm): Use __abs instead of std::abs.
* testsuite/experimental/numeric/77801.cc: New test.
* testsuite/experimental/numeric/gcd.cc: Test unsigned inputs.
* testsuite/experimental/numeric/lcm.cc: Likewise.
2016-09-29 Ville Voutilainen <ville.voutilainen@gmail.com>
Make optional::reset noexcept, make optional::value

22
libstdc++-v3/include/experimental/numeric
View file

@ -39,8 +39,8 @@
# include <bits/c++14_warning.h>
#else
#include <numeric>
#include <experimental/type_traits>
#include <cmath>
namespace std _GLIBCXX_VISIBILITY(default)
{
@ -52,6 +52,19 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
#define __cpp_lib_experimental_gcd_lcm 201411
// std::abs is not constexpr and doesn't support unsigned integers.
template<typename _Tp>
constexpr
enable_if_t<__and_<is_integral<_Tp>, is_signed<_Tp>>::value, _Tp>
__abs(_Tp __val)
{ return __val < 0 ? -__val : __val; }
template<typename _Tp>
constexpr
enable_if_t<__and_<is_integral<_Tp>, is_unsigned<_Tp>>::value, _Tp>
__abs(_Tp __val)
{ return __val; }
// Greatest common divisor
template<typename _Mn, typename _Nn>
constexpr common_type_t<_Mn, _Nn>
@ -60,8 +73,8 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
static_assert(is_integral<_Mn>::value, "arguments to gcd are integers");
static_assert(is_integral<_Nn>::value, "arguments to gcd are integers");
return __m == 0 ? std::abs(__n)
: __n == 0 ? std::abs(__m)
return __m == 0 ? fundamentals_v2::__abs(__n)
: __n == 0 ? fundamentals_v2::__abs(__m)
: fundamentals_v2::gcd(__n, __m % __n);
}
@ -74,7 +87,8 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
static_assert(is_integral<_Nn>::value, "arguments to lcm are integers");
return (__m != 0 && __n != 0)
? (std::abs(__m) / fundamentals_v2::gcd(__m, __n)) * std::abs(__n)
? (fundamentals_v2::__abs(__m) / fundamentals_v2::gcd(__m, __n))
* fundamentals_v2::__abs(__n)
: 0;
}

22
libstdc++-v3/testsuite/experimental/numeric/77801.cc Normal file
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@ -0,0 +1,22 @@
// Copyright (C) 2016 Free Software Foundation, Inc.
//
// This file is part of the GNU ISO C++ Library. This library is free
// software; you can redistribute it and/or modify it under the
// terms of the GNU General Public License as published by the
// Free Software Foundation; either version 3, or (at your option)
// any later version.
// This 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 General Public License for more details.
// You should have received a copy of the GNU General Public License along
// with this library; see the file COPYING3. If not see
// <http://www.gnu.org/licenses/>.
// { dg-do compile { target c++14 } }
#include <cstdlib>
#include <experimental/numeric>
constexpr int i = std::experimental::gcd(4L, 5L); // PR libstdc++/77801

4
libstdc++-v3/testsuite/experimental/numeric/gcd.cc
View file

@ -25,3 +25,7 @@ static_assert(lcm(21, 6) == 42, "");
static_assert(lcm(41, 0) == 0, "LCD with zero is zero");
static_assert(lcm(0, 7) == 0, "LCD with zero is zero");
static_assert(lcm(0, 0) == 0, "no division by zero");
static_assert(lcm(1u, 2) == 2, "unsigned and signed");
static_assert(lcm(3, 4u) == 12, "signed and unsigned");
static_assert(lcm(5u, 6u) == 30, "unsigned and unsigned");

3
libstdc++-v3/testsuite/experimental/numeric/lcm.cc
View file

@ -29,3 +29,6 @@ static_assert( gcd(0, 13) == 13, "GCD of any number and 0 is that number" );
static_assert( gcd(29, 0) == 29, "GCD of any number and 0 is that number" );
static_assert( gcd(0, 0) == 0, "" );
static_assert(gcd(1u, 2) == 1, "unsigned and signed");
static_assert(gcd(3, 4u) == 1, "signed and unsigned");
static_assert(gcd(5u, 6u) == 1, "unsigned and unsigned");