PR tree-optimization/86741 - ICE in -Warray-bounds indexing into an object of incomplete type

gcc/ChangeLog:

	PR tree-optimization/86741
	* tree-vrp.c (vrp_prop::check_mem_ref): Avoid incomplete types.

gcc/testsuite/ChangeLog:

	PR tree-optimization/86741
	* gcc.dg/Warray-bounds-33.c: New test.

From-SVN: r263166

gcc/ChangeLog

+2018-07-31  Martin Sebor  <msebor@redhat.com>
+
+	PR tree-optimization/86741
+	* tree-vrp.c (vrp_prop::check_mem_ref): Avoid incomplete types.
+
 2018-07-31  Andreas Krebbel  <krebbel@linux.ibm.com>
 
 	* config/s390/s390.c (s390_expand_setmem): Make the unrolling to

gcc/testsuite/ChangeLog

+2018-07-31  Martin Sebor  <msebor@redhat.com>
+
+	PR tree-optimization/86741
+	* gcc.dg/Warray-bounds-33.c: New test.
+
 2018-07-31  Andreas Krebbel  <krebbel@linux.ibm.com>
 
 	* gcc.target/s390/memset-1.c: Improve testcase.

gcc/testsuite/gcc.dg/Warray-bounds-33.c

+/* PR tree-optimization/86741 - ICE in -Warray-bounds indexing into
+   an object of incomplete type
+   { dg-do compile }
+   { dg-options "-O2 -Wall" }  */
+
+struct S
+{
+  int s;
+};
+
+void f (void);
+
+void test_void (void)
+{
+  extern void v;
+  struct S *b = (struct S*)&v;
+  if (b->s)
+    f ();
+}
+
+void test_incomplete_enum (void)
+{
+  extern enum E e;
+  struct S *b = (struct S*)&e;
+  if (b->s)
+    f ();
+}
+
+void test_func (void)
+{
+  struct S *b = (struct S*)&f;
+  if (b->s)
+    f ();
+}
+
+/* { dg-prune-output "taking address of expression of type .void." } */

gcc/tree-vrp.c

@@ -5048,9 +5048,12 @@ vrp_prop::check_mem_ref (location_t location, tree ref, bool ignore_off_by_one)
      a reference/subscript via a pointer to an object that is not
      an element of an array.  References to members of structs and
      unions are excluded because MEM_REF doesn't make it possible
-     to identify the member where the reference originated.  */
+     to identify the member where the reference originated.
+     Incomplete types are excluded as well because their size is
+     not known.  */
   tree reftype = TREE_TYPE (arg);
   if (POINTER_TYPE_P (reftype)
+      || !COMPLETE_TYPE_P (reftype)
       || RECORD_OR_UNION_TYPE_P (reftype))
     return;