[Bug middle-end/88226] New: missing warning on fprintf, fputs, and puts with an unterminated array

[msebor at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=88226

            Bug ID: 88226
           Summary: missing warning on fprintf, fputs, and puts with an
                    unterminated array
           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: ---

Of the invalid uses of an unterminated character array below GCC diagnoses just
the first and none of the others.

$ cat t.c && gcc -O2 -S -Wall -fdump-tree-optimized=/dev/stdout t.c
#include <stdio.h>

const char c = 'a';

void g (FILE *f)
{
  printf ("%s", &c);        // warning (good)

  fprintf (f, "%s", &c);    // missing warning
  fputs (&c, f);            // same
  puts (&c);                // same
}
t.c: In function ‘g’:
t.c:7:12: warning: ‘%s’ directive argument is not a nul-terminated string
[-Wformat-overflow=]
    7 |   printf ("%s", &c);        // warning (good)
      |   ~~~~~~~~~^~~~~~~~
t.c:3:12: note: referenced argument declared here
    3 | const char c = 'a';
      |            ^

;; Function g (g, funcdef_no=11, decl_uid=2409, cgraph_uid=12, symbol_order=12)

g (struct FILE * f)
{
  <bb 2> [local count: 1073741824]:
  printf ("%s", &c);
  __builtin_fputs (&c, f_3(D));
  fputs (&c, f_3(D));
  puts (&c); [tail call]
  return;

}