[Bug c/116386] New: false-positive -Werror=return-type when compiling with -fsanitize=thread

[pierrick.bouvier at posteo dot net via Gcc-bugs]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=116386

            Bug ID: 116386
           Summary: false-positive -Werror=return-type when compiling with
                    -fsanitize=thread
           Product: gcc
           Version: 14.2.0
            Status: UNCONFIRMED
          Severity: normal
          Priority: P3
         Component: c
          Assignee: unassigned at gcc dot gnu.org
          Reporter: pierrick.bouvier at posteo dot net
  Target Milestone: ---

$ cat file.c
#include <assert.h>
int tab[10];
int f()
{
    for (int i = 0; i < 10; ++i) 
    {
        if (tab[i]) {
            return 0;
        }
    }
    assert(0);
}

$ gcc -c -Wall -Werror file.c
# no warning
$ gcc -c -Wall -Werror file.c -fsanitize=thread 
file.c: In function ‘f’:
file.c:12:1: error: control reaches end of non-void function
[-Werror=return-type]

It seems like assert(0) is ignored during control flow analysis when compiling
with thread sanitizer.

Found on gcc 12.2.0 (debian stable), and still present on gcc 14.2.0 (debian
unstable).