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G++ LTO bug?
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$ type g++-5 | |
g++-5 is /usr/bin/g++-5 | |
$ g++-5 --version | |
g++-5 (Debian 5.2.1-23) 5.2.1 20151028 | |
Copyright (C) 2015 Free Software Foundation, Inc. | |
This is free software; see the source for copying conditions. There is NO | |
warranty; not even for MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. | |
$ dpkg -l g++-5 libstdc++-5-dev | |
Desired=Unknown/Install/Remove/Purge/Hold | |
| Status=Not/Inst/Conf-files/Unpacked/halF-conf/Half-inst/trig-aWait/Trig-pend | |
|/ Err?=(none)/Reinst-required (Status,Err: uppercase=bad) | |
||/ Name Version Architecture Description | |
+++-==============-============-============-================================= | |
ii g++-5 5.2.1-23 i386 GNU C++ compiler | |
ii libstdc++-5-de 5.2.1-23 i386 GNU Standard C++ Library v3 (deve | |
$ uname -a | |
Linux deodand 4.2.0-1-686-pae #1 SMP Debian 4.2.3-2 (2015-10-14) i686 GNU/Linux | |
$ cat t.cc | |
#include <regex> | |
#include <string> | |
int main() { | |
std::string a; | |
std::regex r("x"); | |
return std::regex_match(a, r); | |
} | |
$ g++-5 -O2 -std=c++11 -Wuninitialized -c t.cc | |
$ g++-5 -O2 -std=c++11 -Wuninitialized -o t t.o | |
$ g++-5 -O2 -flto -fuse-linker-plugin -std=c++11 -Wuninitialized -c t.cc | |
$ g++-5 -O2 -flto -fuse-linker-plugin -std=c++11 -Wuninitialized -o t t.o | |
/usr/include/c++/5/bits/regex_compiler.tcc: In member function ‘_M_alternative’: | |
/usr/include/c++/5/bits/regex_compiler.tcc:266:8: warning: ‘__n’ may be used uninitialized in this function [-Wmaybe-uninitialized] | |
for (long __i = 0; __i < __n; ++__i) | |
^ | |
/usr/include/c++/5/bits/regex_compiler.tcc:230:9: note: ‘__n’ was declared here | |
long __n; | |
^ |
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