[Bug tree-optimization/84228] New: Bogus -Wstringop-truncation with -g

["mpolacek at gcc dot gnu.org" <gcc-bugzilla at gcc dot gnu dot org>]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=84228

            Bug ID: 84228
           Summary: Bogus -Wstringop-truncation with -g
           Product: gcc
           Version: 8.0
            Status: UNCONFIRMED
          Severity: normal
          Priority: P3
         Component: tree-optimization
          Assignee: unassigned at gcc dot gnu.org
          Reporter: mpolacek at gcc dot gnu.org
  Target Milestone: ---

char *strncpy (char *, const char *, __SIZE_TYPE__);
struct S
{
  char arr[64];
};

int
foo (struct S *p1, const char *a)
{
  if (a)
    goto err;
  strncpy (p1->arr, a, sizeof p1->arr);
  p1->arr[3] = '\0';
err:
  return 0;
}

$ ./cc1 -quiet t.c -Wstringop-truncation -O2 -g
t.c: In function ‘foo’:
t.c:12:3: warning: ‘strncpy’ specified bound 64 equals destination size
[-Wstringop-truncation]
   strncpy (p1->arr, a, sizeof p1->arr);
   ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

the warning is gone without -g.