[Bug analyzer/97568] New: -fanalyzer assumes that an extern const pointer is NULL

[vincent-gcc at vinc17 dot net via Gcc-bugs]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=97568

            Bug ID: 97568
           Summary: -fanalyzer assumes that an extern const pointer is
                    NULL
           Product: gcc
           Version: 11.0
            Status: UNCONFIRMED
          Severity: normal
          Priority: P3
         Component: analyzer
          Assignee: dmalcolm at gcc dot gnu.org
          Reporter: vincent-gcc at vinc17 dot net
  Target Milestone: ---

On the following program tst.c:

extern int *const s;
int main (void)
{
  return s[0];
}

I get under Debian/unstable:


zira:~> gcc-snapshot -fanalyzer -c tst.c
tst.c: In function 'main':
tst.c:4:11: warning: dereference of NULL '0' [CWE-690]
[-Wanalyzer-null-dereference]
    4 |   return s[0];
      |          ~^~~
  'main': event 1
    |
    |

This occurs with:

gcc (Debian 20201023-1) 11.0.0 20201023 (experimental) [master revision
d08d481912b:b3da6ca6235:9e3b9ddb996f18d541a3e03611d46c3a6c0c0b5f]

There was no such issue with:

gcc (Debian 20201002-1) 11.0.0 20201002 (experimental) [master revision
05d39f0de9e:767e018251e:1d3e12c469e5f5627c2e271232e1a3d8a88783be]