http://gcc.gnu.org/bugzilla/show_bug.cgi?id=59709
Bug ID: 59709
Summary: break program behavior with optimization
Product: gcc
Version: unknown
Status: UNCONFIRMED
Severity: normal
Priority: P3
Component: c++
Assignee: unassigned at gcc dot gnu.org
Reporter: faithandbrave at gmail dot com
Hi, I encountered difficult problem. If I use -O2 option, follow code behavior
be break. (in GCC 4.8.2)
#include <iostream>
#include <string>
#include <boost/spirit/include/qi.hpp>
namespace qi = boost::spirit::qi;
int main()
{
const std::string input = "hello:";
auto rule = *(qi::char_ - ':') >> ':';
std::string::const_iterator it = input.begin();
std::string result;
if (qi::parse(it, input.end(), rule, result)) {
std::cout << "parse successful" << std::endl;
}
else {
std::cout << "parse failed" << std::endl;
}
}
If I don't use optimization, the problem result is "parse successful". But if I
use optimization, the problem result is output "parse failed" or output
nothing.
If I don't use `auto` and I write type, the problem result is "parse
successful" correctly :
#include <iostream>
#include <string>
#include <boost/spirit/include/qi.hpp>
namespace qi = boost::spirit::qi;
int main()
{
const std::string input = "hello:";
qi::rule<std::string::const_iterator, std::string()> rule = *(qi::char_ -
':') >> ':';
std::string::const_iterator it = input.begin();
std::string result;
if (qi::parse(it, input.end(), rule, result)) {
std::cout << "parse successful" << std::endl;
}
else {
std::cout << "parse failed" << std::endl;
}
}
I couldn't write minimal code without Boost.Spirit. Sorry.
