diff --git a/lib/AST/ASTContext.cpp b/lib/AST/ASTContext.cpp
index f47e28b..51815d5 100644
--- a/lib/AST/ASTContext.cpp
+++ b/lib/AST/ASTContext.cpp
@@ -1371,8 +1371,7 @@
 
 /// getDependentSizedArrayType - Returns a non-unique reference to
 /// the type for a dependently-sized array of the specified element
-/// type. FIXME: We will need these to be uniqued, or at least
-/// comparable, at some point.
+/// type.
 QualType ASTContext::getDependentSizedArrayType(QualType EltTy,
                                                 Expr *NumElts,
                                                 ArrayType::ArraySizeModifier ASM,
@@ -1381,15 +1380,38 @@
   assert((NumElts->isTypeDependent() || NumElts->isValueDependent()) && 
          "Size must be type- or value-dependent!");
 
-  // Since we don't unique expressions, it isn't possible to unique
-  // dependently-sized array types.
+  llvm::FoldingSetNodeID ID;
+  DependentSizedArrayType::Profile(ID, *this, getCanonicalType(EltTy), ASM, 
+                                   EltTypeQuals, NumElts);
 
-  DependentSizedArrayType *New =
-    new (*this,8) DependentSizedArrayType(EltTy, QualType(),
-                                          NumElts, ASM, EltTypeQuals,
-                                          Brackets);
-
-  DependentSizedArrayTypes.push_back(New);
+  void *InsertPos = 0;
+  DependentSizedArrayType *Canon
+    = DependentSizedArrayTypes.FindNodeOrInsertPos(ID, InsertPos);
+  DependentSizedArrayType *New;
+  if (Canon) {
+    // We already have a canonical version of this array type; use it as
+    // the canonical type for a newly-built type.
+    New = new (*this,8) DependentSizedArrayType(*this, EltTy, 
+                                                QualType(Canon, 0),
+                                                NumElts, ASM, EltTypeQuals,
+                                                Brackets);
+  } else {
+    QualType CanonEltTy = getCanonicalType(EltTy);
+    if (CanonEltTy == EltTy) {
+      New = new (*this,8) DependentSizedArrayType(*this, EltTy, QualType(),
+                                                  NumElts, ASM, EltTypeQuals,
+                                                  Brackets);
+      DependentSizedArrayTypes.InsertNode(New, InsertPos);
+    } else {
+      QualType Canon = getDependentSizedArrayType(CanonEltTy, NumElts,
+                                                  ASM, EltTypeQuals,
+                                                  SourceRange());
+      New = new (*this,8) DependentSizedArrayType(*this, EltTy, Canon,
+                                                  NumElts, ASM, EltTypeQuals,
+                                                  Brackets);      
+    }
+  }
+  
   Types.push_back(New);
   return QualType(New, 0);
 }
diff --git a/lib/AST/Type.cpp b/lib/AST/Type.cpp
index c8e317c..ed91e80 100644
--- a/lib/AST/Type.cpp
+++ b/lib/AST/Type.cpp
@@ -64,6 +64,18 @@
   C.Deallocate(this);
 }
 
+void DependentSizedArrayType::Profile(llvm::FoldingSetNodeID &ID, 
+                                      ASTContext &Context,
+                                      QualType ET,
+                                      ArraySizeModifier SizeMod,
+                                      unsigned TypeQuals,
+                                      Expr *E) {
+  ID.AddPointer(ET.getAsOpaquePtr());
+  ID.AddInteger(SizeMod);
+  ID.AddInteger(TypeQuals);
+  E->Profile(ID, Context, true);
+}
+
 void DependentSizedExtVectorType::Destroy(ASTContext& C) {
   // FIXME: Deallocate size expression, once we're cloning properly.
 //  if (SizeExpr)