[Bug sanitizer/81275] New: [gcc7 gcc8] -fsanitize=thread produce incorrect -Wreturn-type warning

[dimhen at gmail dot com]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=81275

            Bug ID: 81275
           Summary: [gcc7 gcc8] -fsanitize=thread produce incorrect
                    -Wreturn-type warning
           Product: gcc
           Version: unknown
            Status: UNCONFIRMED
          Severity: normal
          Priority: P3
         Component: sanitizer
          Assignee: unassigned at gcc dot gnu.org
          Reporter: dimhen at gmail dot com
                CC: dodji at gcc dot gnu.org, dvyukov at gcc dot gnu.org,
                    jakub at gcc dot gnu.org, kcc at gcc dot gnu.org, marxin at gcc dot gnu.org
  Target Milestone: ---

g++ -Werror=return-type -c t.cpp # no warning

g++ -Werror=return-type -fsanitize=thread -c t.cpp # warning
t.cpp:14:1: error: control reaches end of non-void function
[-Werror=return-type]
 }
 ^


Affected versions:
gcc version 7.0.1 20170420 (experimental) [trunk revision 247015] (GCC)
gcc version 8.0.0 20170625 (experimental) [trunk revision 249632] (GCC)

-fsanitize={address,undefined} unaffected

$ cat t.cpp
int f1(int a, int b)
{
    switch (a) {
    case 0:
        switch (b) {
        default:
            return 0;
        }
        break; // NO warning if commented out

    default:
        return 0;
    }
}