resurrected sparse triangular solver

Eigen/src/Core/util/Constants.h

@@ -199,20 +199,16 @@ enum {
   NoUnrolling
 };
 
-enum {
-  Dense   = 0,
-  Sparse  = SparseBit
-};
-
 enum {
   ColMajor = 0,
   RowMajor = RowMajorBit
 };
 
 enum {
-  NoDirectAccess = 0,
+  IsDense         = 0,
+  NoDirectAccess  = 0,
   HasDirectAccess = DirectAccessBit,
-  IsSparse = SparseBit
+  IsSparse        = SparseBit
 };
 
 const int FullyCoherentAccessPattern  = 0x1;

Eigen/src/Core/util/XprHelper.h

@@ -110,7 +110,7 @@ template<int _Rows, int _Cols> struct ei_size_at_compile_time
 
 template<typename T, int Sparseness = ei_traits<T>::Flags&SparseBit> class ei_eval;
 
-template<typename T> struct ei_eval<T,Dense>
+template<typename T> struct ei_eval<T,IsDense>
 {
   typedef Matrix<typename ei_traits<T>::Scalar,
                 ei_traits<T>::RowsAtCompileTime,