re PR bootstrap/78817 (stage2 bootstrap failure in vec.h:1613:5: error: argument…

re PR bootstrap/78817 (stage2 bootstrap failure in vec.h:1613:5: error: argument 1 null where non-null expected after r243661)

	PR bootstrap/78817
	* vec.h (vec<T, va_heap, vl_ptr>::safe_grow_cleared): Revert
	2016-12-15 change.

From-SVN: r243883

gcc/ChangeLog

+2016-12-22  Jakub Jelinek  <jakub@redhat.com>
+
+	PR bootstrap/78817
+	* vec.h (vec<T, va_heap, vl_ptr>::safe_grow_cleared): Revert
+	2016-12-15 change.
+
 2016-12-21  Vladimir Makarov  <vmakarov@redhat.com>
 
 	PR rtl-optimization/78580

gcc/vec.h

@@ -1607,16 +1607,10 @@ inline void
 vec<T, va_heap, vl_ptr>::safe_grow_cleared (unsigned len MEM_STAT_DECL)
 {
   unsigned oldlen = length ();
-  gcc_checking_assert (oldlen <= len);
-
-  if (size_t sz = sizeof (T) * (len - oldlen))
-    {
-      safe_grow (len PASS_MEM_STAT);
-
-      T *p = address ();
-      gcc_assert (p != NULL);
-      memset (p + oldlen, 0, sz);
-    }
+  size_t sz = sizeof (T) * (len - oldlen);
+  safe_grow (len PASS_MEM_STAT);
+  if (sz != 0)
+    memset (&(address ()[oldlen]), 0, sz);
 }