id,summary,reporter,owner,description,type,status,milestone,component,version,severity,resolution,keywords,cc
2655,pure virtual function called under gcc -O2,eherbst@…,Eric Niebler,"The following code results in a pure virtual function call under gcc-4.3.0 20080428 (red hat 4.3.0-8) with -O2 but not with -O1. The innermost non-error-handling stack frame gdb shows is 

boost::xpressive::detail::end_matcher::match<__gnu_cxx::__normal_iterator<char const*, std::string>, boost::xpressive::detail::no_next>

at boost/xpressive/detail/core/flow_control.hpp:64.

---
#include <string>
#include <boost/xpressive/xpressive_static.hpp>
#include <boost/xpressive/regex_algorithms.hpp>
using std::string;
namespace xpr = boost::xpressive;

int main()
{
	string text = ""at"";
	xpr::sregex r1 = xpr::as_xpr('a'),
		r2 = 'b' >> r1,
		r3 = r2 | r1;
	xpr::regex_replace(text, r3, string(""""));
	return 0;
}
---

The problem goes away if I do any one of these:
- switch the order of the alternation
- replace 'r1' in the definition of r3 with  xpr::as_xpr('a')
- replace 'r2' in the definition of r3 with  ('b' >> r1)
- match to a string not starting with 'a'

It does not go away if I do one of these:
- change the 'b' in r2 to 'a'
- stick a by_ref() around r1 in the definition of r2

Any ideas?

Thank you.",Support Requests,closed,Boost 1.38.0,xpressive,Boost 1.37.0,Problem,fixed,,