[Bug tree-optimization/86701] New: Optimize strlen called on std::string c_str()

[david.bolvansky at gmail dot com]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=86701

            Bug ID: 86701
           Summary: Optimize strlen called on std::string c_str()
           Product: gcc
           Version: 9.0
            Status: UNCONFIRMED
          Severity: normal
          Priority: P3
         Component: tree-optimization
          Assignee: unassigned at gcc dot gnu.org
          Reporter: david.bolvansky at gmail dot com
  Target Milestone: ---

Transform:
int lenstr(std::string &str) {
    return strlen(str.c_str() /* .data() */);
}

To:
int lenstr(std::string &str) {
    return str.length();
}