[Bug middle-end/90037] New: [9 Regression] -Wnull-dereference false positive after r269302

[msebor at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=90037

            Bug ID: 90037
           Summary: [9 Regression] -Wnull-dereference false positive after
                    r269302
           Product: gcc
           Version: 9.0
            Status: UNCONFIRMED
          Severity: normal
          Priority: P3
         Component: middle-end
          Assignee: unassigned at gcc dot gnu.org
          Reporter: msebor at gcc dot gnu.org
  Target Milestone: ---

Created attachment 46134
  --> https://gcc.gnu.org/bugzilla/attachment.cgi?id=46134&action=edit
Test case.

The false positive for the attached test case was reported in 
https://bugzilla.redhat.com/show_bug.cgi?id=1698478:

$ gcc -O2 -S -Wall -Wextra -Wnull-dereference bz1698478.c
bz1698478.c: In function ‘parse_with_separator’:
bz1698478.c:121:14: warning: potential null pointer dereference
[-Wnull-dereference]
  121 |       grp = (*g == '+' ? 0 : getgrnam (g));
      |              ^~