diff --git a/gcc/ChangeLog b/gcc/ChangeLog
index 1215863c452..8ac232141a9 100644
--- a/gcc/ChangeLog
+++ b/gcc/ChangeLog
@@ -1,3 +1,9 @@
+2008-03-30  H.J. Lu  <hongjiu.lu@intel.com>
+
+	PR target/38781
+	* config/i386/i386.c (classify_argument): Check total size of
+	structure.
+
 2009-03-30  Martin Jambor  <mjambor@suse.cz>
 
 	* ipa-prop.h (jump_func_type): Rename IPA_UNKNOWN, IPA_CONST,
diff --git a/gcc/config/i386/i386.c b/gcc/config/i386/i386.c
index 3dec02f3acd..09a6597b894 100644
--- a/gcc/config/i386/i386.c
+++ b/gcc/config/i386/i386.c
@@ -4942,6 +4942,8 @@ classify_argument (enum machine_mode mode, const_tree type,
 		    }
 		  else
 		    {
+		      int pos;
+
 		      type = TREE_TYPE (field);
 
 		      /* Flexible array member is ignored.  */
@@ -4970,13 +4972,10 @@ classify_argument (enum machine_mode mode, const_tree type,
 						+ bit_offset) % 256);
 		      if (!num)
 			return 0;
-		      for (i = 0; i < num; i++)
-			{
-			  int pos =
-			    (int_bit_position (field) + (bit_offset % 64)) / 8 / 8;
-			  classes[i + pos] =
-			    merge_classes (subclasses[i], classes[i + pos]);
-			}
+		      pos = (int_bit_position (field) + (bit_offset % 64)) / 8 / 8;
+		      for (i = 0; i < num && (i + pos) < words; i++)
+			classes[i + pos] =
+			  merge_classes (subclasses[i], classes[i + pos]);
 		    }
 		}
 	    }