re PR libstdc++/51795 (linear_congruential_engine doesn't work correctly)

2012-04-29  Marc Glisse  <marc.glisse@inria.fr>
	    Paolo Carlini  <paolo.carlini@oracle.com>

	PR libstdc++/51795
	* include/bits/stl_algobase.h (__lg<>(_Size)): Remove.
	(__lg(int), __lg(unsigned), __lg(long), __lg(unsigned long),
	__lg(long long), __lg(unsigned long long)): Define constexpr.
	* include/bits/random.h (_Mod<>): Overcome Schrage's algorithm
	limitations.
	(__mod): Adjust.
	(linear_congruential): Remove FIXME static_assert.
	* include/bits/random.tcc (_Mod<>): Adjust.
	* testsuite/26_numerics/random/linear_congruential_engine/operators/
	51795.cc: New.

Co-Authored-By: Paolo Carlini <paolo.carlini@oracle.com>

From-SVN: r186948

1 files changed, 45 insertions, 0 deletions

diff --git a/libstdc++-v3/testsuite/26_numerics/random/linear_congruential_engine/operators/51795.cc b/libstdc++-v3/testsuite/26_numerics/random/linear_congruential_engine/operators/51795.cc
new file mode 100644
index 0000000..a626df0
--- /dev/null
+++ b/libstdc++-v3/testsuite/26_numerics/random/linear_congruential_engine/operators/51795.cc
@@ -0,0 +1,45 @@
+// { dg-options "-std=gnu++11" }
+// { dg-require-cstdint "" }
+//
+// Copyright (C) 2012 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/>.
+
+// 26.5.3.1 class template linear_congruential_engine [rand.eng.lcong]
+
+#include <random>
+#include <testsuite_hooks.h>
+
+void test01()
+{
+  bool test __attribute__((unused)) = true;
+
+  typedef std::linear_congruential_engine<std::uint64_t, 1103515245ULL,
+					  12345, 2147483648ULL> engine;
+  engine eng(1103527590ULL);
+
+  for (unsigned it = 0; it < 1000; ++it)
+    {
+      std::uint64_t num = eng();
+      VERIFY( (num >= eng.min() && num <= eng.max()) );
+    }
+}
+
+int main()
+{
+  test01();
+  return 0;
+}