https://gcc.gnu.org/bugzilla/show_bug.cgi?id=78717
--- Comment #2 from AK <hiraditya at msn dot com> --- With -O3 I see only the following definition of find which calls the real find function I was expecting to be visible in the gimple. D.12805 = _ZNKSt7__cxx1112basic_stringIcSt11char_traitsIcESaIcEE4findERKS4_mD.11635 (s1D.12794, s2D.12795, 0); std::__cxx11::basic_string<_CharT, _Traits, _Alloc>::size_type std::__cxx11::basic_string<_CharT, _Traits, _Alloc>::find(const std::__cxx11::basic_string<_CharT, _Traits, _Alloc>&, std::__cxx11::basic_string<_CharT, _Traits, _Alloc>::size_type) const But after I #defined _GLIBCXX_DEBUG in test.cpp (before including string), I can see the find function.
