Nathan Myers  <ncm@cantrip.org>

	* include/bits/basic_string.h
	(replace(__pos, __n1, __s, __n2)): Optimize by avoiding
	temporaries (i.e., call _M_replace_safe) when possible.
	(replace(__pos, __n, __str)): Call replace(__pos, __n1, __s, __n2).
	(replace(__pos, __n1, __s)): Call replace(__pos, __n1, __s , __n2).
	(replace(__i1, __i2, __str)): Call replace(__i1, __i2, __s, __n).
	(replace(__i1, __i2, __s)): Call replace(__i1, __i2, __s, __n).
	(replace(__i1, __i2, __s, __n)): Call replace(__pos1, __n1, __s, __n2).
	* include/bits/basic_string.tcc
	(replace(__pos1, __n1, __str, __pos2, __n2)): Call
	replace(__pos, __n1, __s, __n2).
	* testsuite/21_strings/replace.cc (test03): New testcases.

	* include/bits/basic_string.h (insert(__pos, __s, __n)):
	Adjust comparison wrt overflow.

Co-Authored-By: Nathan Myers <ncm@cantrip.org>

From-SVN: r48834