[multiple changes]
2008-07-05 Paolo Carlini <paolo.carlini@oracle.com> * include/std/ratio: Prefer __INTMAX_MAX__ to INTMAX_MAX (INTMAX_MIN). 2008-07-05 Chris Fairles <chris.fairles@gmail.com> * include/std/ratio: Documentation for std::ratio class. Add conditions to ratio_less to prevent overflow. * testsuite/20_util/ratio/comparisons/comp2.cc: New. * testsuite/20_util/ratio/cons/cons_overflow.cc: Update dg-error line numbers. From-SVN: r137504
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@ -1,3 +1,15 @@
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2008-07-05 Paolo Carlini <paolo.carlini@oracle.com>
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* include/std/ratio: Prefer __INTMAX_MAX__ to INTMAX_MAX (INTMAX_MIN).
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2008-07-05 Chris Fairles <chris.fairles@gmail.com>
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* include/std/ratio: Documentation for std::ratio class. Add conditions
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to ratio_less to prevent overflow.
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* testsuite/20_util/ratio/comparisons/comp2.cc: New.
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* testsuite/20_util/ratio/cons/cons_overflow.cc: Update dg-error line
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numbers.
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2008-07-04 Chris Fairles <chris.fairles@gmail.com>
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2008-07-04 Chris Fairles <chris.fairles@gmail.com>
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* include/std/ratio: New, per N2661.
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* include/std/ratio: New, per N2661.
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@ -96,10 +96,10 @@ namespace std
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"overflow in multiplication");
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"overflow in multiplication");
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static_assert(__a0 * __b1 + __b0 * __a1 < (__c >> 1),
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static_assert(__a0 * __b1 + __b0 * __a1 < (__c >> 1),
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"overflow in multiplication");
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"overflow in multiplication");
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static_assert(__b0 * __a0 <= INTMAX_MAX,
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static_assert(__b0 * __a0 <= __INTMAX_MAX__,
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"overflow in multiplication");
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"overflow in multiplication");
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static_assert((__a0 * __b1 + __b0 * __a1) * __c <=
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static_assert((__a0 * __b1 + __b0 * __a1) * __c <=
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INTMAX_MAX - __b0 * __a0, "overflow in multiplication");
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__INTMAX_MAX__ - __b0 * __a0, "overflow in multiplication");
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public:
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public:
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static const intmax_t value = _Pn * _Qn;
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static const intmax_t value = _Pn * _Qn;
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@ -108,12 +108,12 @@ namespace std
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// Helpers for __safe_add
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// Helpers for __safe_add
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template<intmax_t _Pn, intmax_t _Qn, bool>
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template<intmax_t _Pn, intmax_t _Qn, bool>
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struct __add_overflow_check_impl
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struct __add_overflow_check_impl
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: integral_constant<bool, (_Pn <= INTMAX_MAX - _Qn)>
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: integral_constant<bool, (_Pn <= __INTMAX_MAX__ - _Qn)>
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{ };
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{ };
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template<intmax_t _Pn, intmax_t _Qn>
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template<intmax_t _Pn, intmax_t _Qn>
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struct __add_overflow_check_impl<_Pn, _Qn, false>
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struct __add_overflow_check_impl<_Pn, _Qn, false>
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: integral_constant<bool, (_Pn >= -INTMAX_MAX - _Qn)>
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: integral_constant<bool, (_Pn >= -__INTMAX_MAX__ - _Qn)>
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{ };
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{ };
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template<intmax_t _Pn, intmax_t _Qn>
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template<intmax_t _Pn, intmax_t _Qn>
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@ -130,12 +130,27 @@ namespace std
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static const intmax_t value = _Pn + _Qn;
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static const intmax_t value = _Pn + _Qn;
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};
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};
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/**
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* @brief Provides compile-time rational arithmetic.
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*
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* This class template represents any finite rational number with a
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* numerator and denominator representable by compile-time constants of
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* type intmax_t. The ratio is simplified when instantiated.
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*
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* For example:
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* @code
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* std::ratio<7,-21>::num == -1;
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* std::ratio<7,-21>::den == 3;
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* @endcode
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*
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*/
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template<intmax_t _Num, intmax_t _Den = 1>
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template<intmax_t _Num, intmax_t _Den = 1>
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struct ratio
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struct ratio
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{
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{
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static_assert(_Den != 0, "denominator cannot be zero");
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static_assert(_Den != 0, "denominator cannot be zero");
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static_assert(_Num > INTMAX_MIN && _Den > INTMAX_MIN, "out of range");
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static_assert(_Num >= -__INTMAX_MAX__ && _Den >= -__INTMAX_MAX__,
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"out of range");
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// Note: sign(N) * abs(N) == N
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// Note: sign(N) * abs(N) == N
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static const intmax_t num =
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static const intmax_t num =
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_Num * __static_sign<_Den>::value / __static_gcd<_Num, _Den>::value;
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_Num * __static_sign<_Den>::value / __static_gcd<_Num, _Den>::value;
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@ -211,10 +226,26 @@ namespace std
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{ };
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{ };
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template<typename _R1, typename _R2>
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template<typename _R1, typename _R2>
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struct ratio_less
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struct __ratio_less_simple_impl
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: integral_constant<bool,
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: integral_constant<bool,
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(__safe_multiply<_R1::num, _R2::den>::value <
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(__safe_multiply<_R1::num, _R2::den>::value
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__safe_multiply<_R2::num, _R1::den>::value)>
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< __safe_multiply<_R2::num, _R1::den>::value)>
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{ };
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// If the denominators are equal or the signs differ, we can just compare
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// numerators, otherwise fallback to the simple cross-multiply method.
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template<typename _R1, typename _R2>
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struct __ratio_less_impl
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: conditional<(_R1::den == _R2::den
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|| (__static_sign<_R1::num>::value
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!= __static_sign<_R2::num>::value)),
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integral_constant<bool, (_R1::num < _R2::num)>,
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__ratio_less_simple_impl<_R1, _R2>>::type
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{ };
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template<typename _R1, typename _R2>
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struct ratio_less
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: __ratio_less_impl<_R1, _R2>::type
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{ };
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{ };
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template<typename _R1, typename _R2>
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template<typename _R1, typename _R2>
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@ -0,0 +1,56 @@
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// { dg-options "-std=gnu++0x" }
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// Copyright (C) 2008 Free Software Foundation
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//
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// This file is part of the GNU ISO C++ Library. This library is free
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// software; you can redistribute it and/or modify it under the
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// terms of the GNU General Public License as published by the
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// Free Software Foundation; either version 2, or (at your option)
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// any later version.
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// This library is distributed in the hope that it will be useful,
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// but WITHOUT ANY WARRANTY; without even the implied warranty of
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// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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// GNU General Public License for more details.
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// You should have received a copy of the GNU General Public License
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// along with this library; see the file COPYING. If not, write to
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// the Free Software Foundation, 51 Franklin Street, Fifth Floor,
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// Boston, MA 02110-1301, USA.
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#include <ratio>
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#include <testsuite_hooks.h>
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#ifdef _GLIBCXX_USE_C99_STDINT_TR1
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static const std::intmax_t M = INTMAX_MAX;
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void
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test01()
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{
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bool test __attribute__((unused)) = true;
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//no overflow with same denominator
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VERIFY(( std::ratio_less<std::ratio<M - 2, M>,
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std::ratio<M - 1, M>>::value == 1 ) );
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VERIFY(( std::ratio_less<std::ratio<M - 1, M>,
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std::ratio<M - 2, M>>::value == 0 ) );
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//no overflow if signs differ
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VERIFY(( std::ratio_less<std::ratio<-M, M - 1>,
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std::ratio<M - 1, M - 2>>::value == 1 ) );
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VERIFY(( std::ratio_less<std::ratio<M - 1, M - 2>,
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std::ratio<-M, M - 1>>::value == 0 ) );
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}
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#endif //_GLIBCXX_USE_C99_STDINT_TR1
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int main()
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{
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#ifdef _GLIBCXX_USE_C99_STDINT_TR1
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test01();
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#endif
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return 0;
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}
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@ -51,8 +51,8 @@ test04()
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// { dg-error "instantiated from here" "" { target *-*-* } 36 }
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// { dg-error "instantiated from here" "" { target *-*-* } 36 }
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// { dg-error "instantiated from here" "" { target *-*-* } 42 }
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// { dg-error "instantiated from here" "" { target *-*-* } 42 }
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// { dg-error "instantiated from here" "" { target *-*-* } 48 }
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// { dg-error "instantiated from here" "" { target *-*-* } 48 }
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// { dg-error "denominator cannot be zero" "" { target *-*-* } 136 }
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// { dg-error "denominator cannot be zero" "" { target *-*-* } 150 }
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// { dg-error "out of range" "" { target *-*-* } 137 }
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// { dg-error "out of range" "" { target *-*-* } 151 }
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// { dg-excess-errors "In instantiation of" }
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// { dg-excess-errors "In instantiation of" }
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#endif //_GLIBCXX_USE_C99_STDINT_TR1
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#endif //_GLIBCXX_USE_C99_STDINT_TR1
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