re PR libstdc++/56202 (SIGFPE (division by zero) in std::binomial_distribution)

2013-02-04  Manuel López-Ibáñez  <manu@gcc.gnu.org>
	    Paolo Carlini  <paolo.carlini@oracle.com>

	PR libstdc++/56202
	* include/bits/random.tcc (binomial_distribution<>::
	_M_waiting(_UniformRandomNumberGenerator&, _IntType)): Avoid
	division by zero.

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

From-SVN: r195722

libstdc++-v3/ChangeLog

+2013-02-04  Manuel López-Ibáñez  <manu@gcc.gnu.org>
+	    Paolo Carlini  <paolo.carlini@oracle.com>
+
+	PR libstdc++/56202
+	* include/bits/random.tcc (binomial_distribution<>::
+	_M_waiting(_UniformRandomNumberGenerator&, _IntType)): Avoid
+	division by zero.
+
 2013-02-03  Richard Sandiford  <rdsandiford@googlemail.com>
 
 	Update copyright years.

libstdc++-v3/include/bits/random.tcc

@@ -1658,6 +1658,12 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
 	do
 	  {
 	    const double __e = -std::log(1.0 - __aurng());
+	    if (__t == __x)
+	      {
+		if (__e)
+		  return __x;
+		continue;
+	      }
 	    __sum += __e / (__t - __x);
 	    __x += 1;
 	  }