2013-10-20  Chris Jefferson  <chris@bubblescope.net>
	    Paolo Carlini  <paolo.carlini@oracle.com>

	PR libstdc++/58800
	* include/bits/stl_algo.h (__unguarded_partition_pivot): Change
	__last - 2 to __last - 1.
	* testsuite/25_algorithms/nth_element/58800.cc: New

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

From-SVN: r203872