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From: "msebor at gcc dot gnu.org" <gcc-bugzilla@gcc.gnu.org>
To: gcc-bugs@gcc.gnu.org
Subject: [Bug middle-end/101455] New: missing -Wstringop-overflow on buffer
 overflow by a complex number
Date: Wed, 14 Jul 2021 17:43:50 +0000
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https://gcc.gnu.org/bugzilla/show_bug.cgi?id=3D101455

            Bug ID: 101455
           Summary: missing -Wstringop-overflow on buffer overflow by a
                    complex number
           Product: gcc
           Version: 11.1.0
            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: ---

The store in the function below overflows the buffer and should be diagnose=
d by
-Wstringop-overflow (which is enabled by default) but isn't.  It's only
diagnosed by -Warray-bounds (which is included in -Wall).

$ cat a.c && gcc -O2 -S -fdump-tree-strlen=3D/dev/stdout a.c
void* f (double x, double i)
{
  _Complex double *p =3D __builtin_malloc (sizeof (double));
  *p =3D __builtin_complex (x, i);
  return p;
}

;; Function f (f, funcdef_no=3D0, decl_uid=3D1944, cgraph_uid=3D1, symbol_o=
rder=3D0)

;; 1 loops found
;;
;; Loop 0
;;  header 0, latch 1
;;  depth 0, outer -1
;;  nodes: 0 1 2
;; 2 succs { 1 }
void * f (double x, double i)
{
  complex double * p;

  <bb 2> [local count: 1073741824]:
  p_3 =3D __builtin_malloc (8);
  REALPART_EXPR <*p_3> =3D x_4(D);
  IMAGPART_EXPR <*p_3> =3D i_5(D);
  return p_3;

}=