diff --git a/gcc/cp/ChangeLog b/gcc/cp/ChangeLog
index 4c9a0dae7f5..b64cf992998 100644
--- a/gcc/cp/ChangeLog
+++ b/gcc/cp/ChangeLog
@@ -1,3 +1,8 @@
+2003-09-03  Mark Mitchell  <mark@codesourcery.com>
+
+	PR c++/12053
+	* class.c (include_empty_classes): Correct logic for ABI version 1.
+
 2003-09-03  Richard Henderson  <rth@redhat.com>
 
 	* optimize.c (optimize_function): Push/pop ggc context around
diff --git a/gcc/cp/class.c b/gcc/cp/class.c
index 3cf161b1e30..1bd63cffa6b 100644
--- a/gcc/cp/class.c
+++ b/gcc/cp/class.c
@@ -4586,7 +4586,19 @@ include_empty_classes (record_layout_info rli)
   if (TREE_CODE (rli_size) == INTEGER_CST
       && INT_CST_LT_UNSIGNED (rli_size, eoc))
     {
-      rli->bitpos = round_up (rli->bitpos, BITS_PER_UNIT);
+      if (!abi_version_at_least (2))
+	/* In version 1 of the ABI, the size of a class that ends with
+	   a bitfield was not rounded up to a whole multiple of a
+	   byte.  Because rli_size_unit_so_far returns only the number
+	   of fully allocated bytes, any extra bits were not included
+	   in the size.  */
+	rli->bitpos = round_down (rli->bitpos, BITS_PER_UNIT);
+      else
+	/* The size should have been rounded to a whole byte.  */
+	my_friendly_assert (tree_int_cst_equal (rli->bitpos,
+						round_down (rli->bitpos,
+							    BITS_PER_UNIT)),
+			    20030903);
       rli->bitpos 
 	= size_binop (PLUS_EXPR, 
 		      rli->bitpos,
diff --git a/gcc/testsuite/ChangeLog b/gcc/testsuite/ChangeLog
index 57b9436a933..a6d708c98fa 100644
--- a/gcc/testsuite/ChangeLog
+++ b/gcc/testsuite/ChangeLog
@@ -1,3 +1,8 @@
+2003-09-03  Mark Mitchell  <mark@codesourcery.com>
+
+	PR c++/12053
+	* g++.dg/abi/layout4.C: New test.
+
 2003-09-02  Scott Brumbaugh  <scottb.lists@verizon.net>
 
 	PR c++/11553
diff --git a/gcc/testsuite/g++.dg/abi/layout4.C b/gcc/testsuite/g++.dg/abi/layout4.C
new file mode 100644
index 00000000000..a1d27ee7f43
--- /dev/null
+++ b/gcc/testsuite/g++.dg/abi/layout4.C
@@ -0,0 +1,18 @@
+// { dg-do run { target i?86-*-* } }
+// { dg-options "-fabi-version=1" }
+
+struct C4
+{
+   int b:30;
+   C4(){};
+};
+
+struct C1:  virtual C4
+{
+  int i;
+};
+
+int main() {
+  if (sizeof (C1) != 12)
+    return 1;
+}