diff --git a/gcc/cp/ChangeLog b/gcc/cp/ChangeLog
index 74af04ca5c5828dab5147cf9800d7f50ad29ed9d..12a3cc6268061f4250ce2639c19b77ac353b5db5 100644
--- a/gcc/cp/ChangeLog
+++ b/gcc/cp/ChangeLog
@@ -1,3 +1,8 @@
+2007-01-11  Simon Martin  <simartin@users.sourceforge.net>
+
+	PR c++/29573
+	* tree.c (cp_tree_equal): Properly handle MODOP_EXPR trees.
+
 2007-01-10  Mark Mitchell  <mark@codesourcery.com>
 
 	PR c++/28999
diff --git a/gcc/cp/tree.c b/gcc/cp/tree.c
index ae3dc4c27867ca7c0201c225037038415c4a082b..742e09014e3a256d6b53ac2422d3e74ce27129a0 100644
--- a/gcc/cp/tree.c
+++ b/gcc/cp/tree.c
@@ -1709,6 +1709,21 @@ cp_tree_equal (tree t1, tree t2)
 	  return cp_tree_equal (o1, o2);
       }
 
+    case MODOP_EXPR:
+      {
+	tree t1_op1, t2_op1;
+
+	if (!cp_tree_equal (TREE_OPERAND (t1, 0), TREE_OPERAND (t2, 0)))
+	  return false;
+
+	t1_op1 = TREE_OPERAND (t1, 1);
+	t2_op1 = TREE_OPERAND (t2, 1);
+	if (TREE_CODE (t1_op1) != TREE_CODE (t2_op1))
+	  return false;
+
+	return cp_tree_equal (TREE_OPERAND (t1, 2), TREE_OPERAND (t2, 2));
+      }
+
     case PTRMEM_CST:
       /* Two pointer-to-members are the same if they point to the same
 	 field or function in the same class.  */
diff --git a/gcc/testsuite/ChangeLog b/gcc/testsuite/ChangeLog
index c63f07418b73ecce86a5d62b7daa4431c3809a62..7b9b3757380cc364ae860880dc2c066f20a2f8b0 100644
--- a/gcc/testsuite/ChangeLog
+++ b/gcc/testsuite/ChangeLog
@@ -1,3 +1,8 @@
+2007-01-11  Simon Martin  <simartin@users.sourceforge.net>
+
+	PR c++/29573
+	* g++.dg/template/sizeof-template-argument.C: New test.
+
 2007-01-11  Jan Hubicka  <jh@suse.cz>
 
 	* gcc.dg/tree-ssa/tailrecursion-4.c: Update dump file.
diff --git a/gcc/testsuite/g++.dg/template/sizeof-template-argument.C b/gcc/testsuite/g++.dg/template/sizeof-template-argument.C
new file mode 100644
index 0000000000000000000000000000000000000000..f7472c3c1a1c15c39936a5168d6991e195c600f7
--- /dev/null
+++ b/gcc/testsuite/g++.dg/template/sizeof-template-argument.C
@@ -0,0 +1,15 @@
+/* This used to ICE (PR c++/29573) */
+/* { dg-do "compile" } */
+
+template<int> struct A {};
+
+template<typename> struct B : A <sizeof(=)> {}; /* { dg-error "parse error in template argument list" } */
+
+template<typename> struct C : A <sizeof(=)> {}; /* { dg-error "parse error in template argument list" } */
+
+int a;
+
+template<typename> struct D : A <sizeof(a=1)> {}; /* This used to ICE as well. */
+
+template<typename> struct E : A <sizeof(a=1)> {}; /* This used to ICE as well. */
+