Fixes the Lvalue computation by actually setting the LvalueBit properly when instantiating tensors of const T. Added a test to check the fix.

2 files changed, 44 insertions, 4 deletions

diff --git a/unsupported/Eigen/CXX11/src/Tensor/TensorTraits.h b/unsupported/Eigen/CXX11/src/Tensor/TensorTraits.h
index a844a4d68..66ddfd554 100644
--- a/unsupported/Eigen/CXX11/src/Tensor/TensorTraits.h
+++ b/unsupported/Eigen/CXX11/src/Tensor/TensorTraits.h
@@ -54,7 +54,7 @@ struct traits<Tensor<Scalar_, NumIndices_, Options_> >
   static const int Layout = Options_ & RowMajor ? RowMajor : ColMajor;
   enum {
     Options = Options_,
-    Flags = compute_tensor_flags<Scalar_, Options_>::ret | LvalueBit,
+    Flags = compute_tensor_flags<Scalar_, Options_>::ret | (is_const<Scalar_>::value ? 0 : LvalueBit),
   };
 };
 
@@ -69,7 +69,7 @@ struct traits<TensorFixedSize<Scalar_, Dimensions, Options_> >
   static const int Layout = Options_ & RowMajor ? RowMajor : ColMajor;
   enum {
     Options = Options_,
-    Flags = compute_tensor_flags<Scalar_, Options_>::ret | LvalueBit,
+    Flags = compute_tensor_flags<Scalar_, Options_>::ret | (is_const<Scalar_>::value ? 0: LvalueBit),
   };
 };
 
@@ -86,7 +86,7 @@ struct traits<TensorMap<PlainObjectType, Options_> >
   static const int Layout = BaseTraits::Layout;
   enum {
     Options = Options_,
-    Flags = ((BaseTraits::Flags | LvalueBit) & ~AlignedBit) | (Options&Aligned ? AlignedBit : 0),
+    Flags = (BaseTraits::Flags & ~AlignedBit) | (Options&Aligned ? AlignedBit : 0),
   };
 };
 
@@ -102,7 +102,7 @@ struct traits<TensorRef<PlainObjectType> >
   static const int Layout = BaseTraits::Layout;
   enum {
     Options = BaseTraits::Options,
-    Flags = ((BaseTraits::Flags | LvalueBit) & ~AlignedBit) | (Options&Aligned ? AlignedBit : 0),
+    Flags = (BaseTraits::Flags & ~AlignedBit) | (Options&Aligned ? AlignedBit : 0),
   };
 };
 
diff --git a/unsupported/test/cxx11_tensor_ref.cpp b/unsupported/test/cxx11_tensor_ref.cpp
index aa369f278..c7b5ecddb 100644
--- a/unsupported/test/cxx11_tensor_ref.cpp
+++ b/unsupported/test/cxx11_tensor_ref.cpp
@@ -196,6 +196,45 @@ static void test_coeff_ref()
 }
 
 
+static void test_nested_ops_with_ref()
+{
+  Tensor<float, 4> t(2, 3, 5, 7);
+  t.setRandom();
+  TensorMap<Tensor<const float, 4> > m(t.data(), 2, 3, 5, 7);
+  array<pair<ptrdiff_t, ptrdiff_t>, 4> paddings;
+  paddings[0] = make_pair(0, 0);
+  paddings[1] = make_pair(2, 1);
+  paddings[2] = make_pair(3, 4);
+  paddings[3] = make_pair(0, 0);
+  Eigen::DSizes<Eigen::DenseIndex, 4> shuffle_dims{0, 1, 2, 3};
+  TensorRef<Tensor<const float, 4> > ref(m.pad(paddings));
+  array<pair<ptrdiff_t, ptrdiff_t>, 4> trivial;
+  trivial[0] = make_pair(0, 0);
+  trivial[1] = make_pair(0, 0);
+  trivial[2] = make_pair(0, 0);
+  trivial[3] = make_pair(0, 0);
+  Tensor<float, 4> padded = ref.shuffle(shuffle_dims).pad(trivial);
+  VERIFY_IS_EQUAL(padded.dimension(0), 2+0);
+  VERIFY_IS_EQUAL(padded.dimension(1), 3+3);
+  VERIFY_IS_EQUAL(padded.dimension(2), 5+7);
+  VERIFY_IS_EQUAL(padded.dimension(3), 7+0);
+
+  for (int i = 0; i < 2; ++i) {
+    for (int j = 0; j < 6; ++j) {
+      for (int k = 0; k < 12; ++k) {
+        for (int l = 0; l < 7; ++l) {
+          if (j >= 2 && j < 5 && k >= 3 && k < 8) {
+            VERIFY_IS_EQUAL(padded(i,j,k,l), t(i,j-2,k-3,l));
+          } else {
+            VERIFY_IS_EQUAL(padded(i,j,k,l), 0.0f);
+          }
+        }
+      }
+    }
+  }
+}
+
+
 void test_cxx11_tensor_ref()
 {
   CALL_SUBTEST(test_simple_lvalue_ref());
@@ -205,4 +244,5 @@ void test_cxx11_tensor_ref()
   CALL_SUBTEST(test_ref_of_ref());
   CALL_SUBTEST(test_ref_in_expr());
   CALL_SUBTEST(test_coeff_ref());
+  CALL_SUBTEST(test_nested_ops_with_ref());
 }