[Bug c/92479] New: missing warnings for unreachable codes with -Wunreachable-code

[tangyixuan at mail dot dlut.edu.cn]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=92479

            Bug ID: 92479
           Summary: missing warnings for unreachable codes with
                    -Wunreachable-code
           Product: gcc
           Version: 10.0
            Status: UNCONFIRMED
          Severity: normal
          Priority: P3
         Component: c
          Assignee: unassigned at gcc dot gnu.org
          Reporter: tangyixuan at mail dot dlut.edu.cn
  Target Milestone: ---

Hi, there is no warning for the unreachable code with [-Wunreachable-code] as
follow. Would it be better to warn developers if the 'break' branch is
unreachable?

$ cat s.c
int main()
{
  for(int i = 1;; i++){
    if(0)
      break;
  }
}

$ gcc -c -Wunreachable-code s.c
no warnings.

$ gcc -v
Target: x86_64-pc-linux-gnu
gcc version 10.0.0 20191110 (experimental) (GCC)

$ clang -c -Wunreachable-code-break s.c
s.c:5:7: warning: 'break' will never be executed [-Wunreachable-code-break]
      break;
      ^~~~~
1 warning generated.

Best regards