re PR libstdc++/52699 (infinite loop generated with -O0)
2012-04-14 Paolo Carlini <paolo.carlini@oracle.com> PR libstdc++/52699 * include/bits/random.tcc (independent_bits_engine<>::operator()()) Avoid various overflows; use common_type on result_type and _RandomNumberEngine::result_type; avoid floating point computations; other smaller tweaks. * include/bits/random.tcc (uniform_int_distribution<>::operator()) Use common_type; assume _UniformRandomNumberGenerator::result_type unsigned; tidy. * include/bits/stl_algobase.h (__lg(unsigned), __lg(unsigned long), __lg(unsigned long long)): Add. From-SVN: r186456
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2012-04-14 Paolo Carlini <paolo.carlini@oracle.com>
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PR libstdc++/52699
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* include/bits/random.tcc (independent_bits_engine<>::operator()())
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Avoid various overflows; use common_type on result_type and
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_RandomNumberEngine::result_type; avoid floating point computations;
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other smaller tweaks.
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* include/bits/random.tcc (uniform_int_distribution<>::operator())
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Use common_type; assume _UniformRandomNumberGenerator::result_type
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unsigned; tidy.
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* include/bits/stl_algobase.h (__lg(unsigned), __lg(unsigned long),
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__lg(unsigned long long)): Add.
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2012-04-14 Alan Modra <amodra@gmail.com>
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PR libstdc++/52839
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@ -730,40 +730,65 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
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independent_bits_engine<_RandomNumberEngine, __w, _UIntType>::
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operator()()
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{
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const long double __r = static_cast<long double>(_M_b.max())
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- static_cast<long double>(_M_b.min()) + 1.0L;
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const result_type __m = std::log(__r) / std::log(2.0L);
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result_type __n, __n0, __y0, __y1, __s0, __s1;
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typedef typename _RandomNumberEngine::result_type _Eresult_type;
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const _Eresult_type __r
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= (_M_b.max() - _M_b.min() < std::numeric_limits<_Eresult_type>::max()
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? _M_b.max() - _M_b.min() + 1 : 0);
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const unsigned __edig = std::numeric_limits<_Eresult_type>::digits;
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const unsigned __m = __r ? std::__lg(__r) : __edig;
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typedef typename std::common_type<_Eresult_type, result_type>::type
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__ctype;
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const unsigned __cdig = std::numeric_limits<__ctype>::digits;
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unsigned __n, __n0;
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__ctype __s0, __s1, __y0, __y1;
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for (size_t __i = 0; __i < 2; ++__i)
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{
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__n = (__w + __m - 1) / __m + __i;
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__n0 = __n - __w % __n;
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const result_type __w0 = __w / __n;
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const result_type __w1 = __w0 + 1;
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__s0 = result_type(1) << __w0;
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__s1 = result_type(1) << __w1;
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__y0 = __s0 * (__r / __s0);
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__y1 = __s1 * (__r / __s1);
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if (__r - __y0 <= __y0 / __n)
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const unsigned __w0 = __w / __n; // __w0 <= __m
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__s0 = 0;
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__s1 = 0;
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if (__w0 < __cdig)
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{
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__s0 = __ctype(1) << __w0;
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__s1 = __s0 << 1;
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}
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__y0 = 0;
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__y1 = 0;
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if (__r)
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{
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__y0 = __s0 * (__r / __s0);
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if (__s1)
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__y1 = __s1 * (__r / __s1);
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if (__r - __y0 <= __y0 / __n)
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break;
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}
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else
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break;
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}
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result_type __sum = 0;
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for (size_t __k = 0; __k < __n0; ++__k)
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{
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result_type __u;
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__ctype __u;
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do
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__u = _M_b() - _M_b.min();
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while (__u >= __y0);
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__sum = __s0 * __sum + __u % __s0;
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while (__y0 && __u >= __y0);
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__sum = __s0 * __sum + (__s0 ? __u % __s0 : __u);
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}
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for (size_t __k = __n0; __k < __n; ++__k)
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{
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result_type __u;
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__ctype __u;
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do
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__u = _M_b() - _M_b.min();
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while (__u >= __y1);
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__sum = __s1 * __sum + __u % __s1;
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while (__y1 && __u >= __y1);
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__sum = __s1 * __sum + (__s1 ? __u % __s1 : __u);
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}
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return __sum;
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}
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@ -840,12 +865,11 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
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operator()(_UniformRandomNumberGenerator& __urng,
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const param_type& __param)
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{
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typedef typename std::make_unsigned<typename
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_UniformRandomNumberGenerator::result_type>::type __urngtype;
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typedef typename _UniformRandomNumberGenerator::result_type
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_Gresult_type;
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typedef typename std::make_unsigned<result_type>::type __utype;
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typedef typename std::conditional<(sizeof(__urngtype)
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> sizeof(__utype)),
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__urngtype, __utype>::type __uctype;
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typedef typename std::common_type<_Gresult_type, __utype>::type
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__uctype;
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const __uctype __urngmin = __urng.min();
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const __uctype __urngmax = __urng.max();
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@ -989,14 +989,26 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
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__lg(int __n)
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{ return sizeof(int) * __CHAR_BIT__ - 1 - __builtin_clz(__n); }
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inline unsigned
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__lg(unsigned __n)
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{ return sizeof(int) * __CHAR_BIT__ - 1 - __builtin_clz(__n); }
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inline long
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__lg(long __n)
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{ return sizeof(long) * __CHAR_BIT__ - 1 - __builtin_clzl(__n); }
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inline unsigned long
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__lg(unsigned long __n)
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{ return sizeof(long) * __CHAR_BIT__ - 1 - __builtin_clzl(__n); }
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inline long long
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__lg(long long __n)
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{ return sizeof(long long) * __CHAR_BIT__ - 1 - __builtin_clzll(__n); }
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inline unsigned long long
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__lg(unsigned long long __n)
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{ return sizeof(long long) * __CHAR_BIT__ - 1 - __builtin_clzll(__n); }
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_GLIBCXX_END_NAMESPACE_VERSION
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_GLIBCXX_BEGIN_NAMESPACE_ALGO
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