A detailed description and tests are given at SO (http://stackoverflow.com/questions/36304204/%D0%A1-regex-segfault-on-long-sequences), in short

std::regex r("\\s+");
std::string out = std::regex_replace(cstring, r, " ");

crashes with SIGSEGV on strings with long space sequences (-O3 can handle around 20k spaces, -O0 handles 12k). Clang produce similar results. Switching to libc++ cures the crashes.


Crash dump shows lengthy stack (35k frames) of 

std::__detail::_Executor<char*, std::allocator<std::__cxx11::sub_match<char*> >, std::__cxx11::regex_traits<char>, true>::_M_dfs

calls.


GCC:

Configured with: /build/gcc-multilib/src/gcc-5-20160209/configure --prefix=/usr --libdir=/usr/lib --libexecdir=/usr/lib --mandir=/usr/share/man --infodir=/usr/share/info --with-bugurl=https://bugs.archlinux.org/ --enable-languages=c,c++,ada,fortran,go,lto,objc,obj-c++ --enable-shared --enable-threads=posix --enable-libmpx --with-system-zlib --with-isl --enable-__cxa_atexit --disable-libunwind-exceptions --enable-clocale=gnu --disable-libstdcxx-pch --disable-libssp --enable-gnu-unique-object --enable-linker-build-id --enable-lto --enable-plugin --enable-install-libiberty --with-linker-hash-style=gnu --enable-gnu-indirect-function --enable-multilib --disable-werror --enable-checking=release
Thread model: posix
gcc version 5.3.0 (GCC)