2006-08-28  Roger Sayle  <roger@eyesopen.com>
	    Paolo Carlini  <pcarlini@suse.de>

	* include/bits/stl_algo.h (__heap_select, __introselect): New.
	(nth_element): New implementation.
	(partial_copy): Use __heap_select.
	* testsuite/performance/25_algorithms/nth_element_worst_case.cc: New.

Co-Authored-By: Paolo Carlini <pcarlini@suse.de>

From-SVN: r116520