Detect "effectively inner/outer" chipping in TensorChipping

unsupported/Eigen/CXX11/src/Tensor/TensorChipping.h

diff --git a/unsupported/Eigen/CXX11/src/Tensor/TensorChipping.h b/unsupported/Eigen/CXX11/src/Tensor/TensorChipping.h
index 000b1fb..f5172cd 100644
--- a/unsupported/Eigen/CXX11/src/Tensor/TensorChipping.h
+++ b/unsupported/Eigen/CXX11/src/Tensor/TensorChipping.h
@@ -173,6 +173,26 @@
     }
     m_inputStride *= input_dims[m_dim.actualDim()];
     m_inputOffset = m_stride * op.offset();
+
+    // Check if chipping is effectively inner or outer: products of dimensions
+    // before or after the chipped dimension is `1`.
+    Index after_chipped_dim_product = 1;
+    for (int i = m_dim.actualDim() + 1; i < NumInputDims; ++i) {
+      after_chipped_dim_product *= input_dims[i];
+    }
+
+    Index before_chipped_dim_product = 1;
+    for (int i = 0; i < m_dim.actualDim(); ++i) {
+      before_chipped_dim_product *= input_dims[i];
+    }
+
+    if (static_cast<int>(Layout) == static_cast<int>(ColMajor)) {
+      m_isEffectivelyInnerChipping = before_chipped_dim_product == 1;
+      m_isEffectivelyOuterChipping = after_chipped_dim_product == 1;
+    } else {
+      m_isEffectivelyInnerChipping = after_chipped_dim_product == 1;
+      m_isEffectivelyOuterChipping = before_chipped_dim_product == 1;
+    }
   }
 
   EIGEN_DEVICE_FUNC EIGEN_STRONG_INLINE const Dimensions& dimensions() const { return m_dimensions; }
@@ -336,13 +356,11 @@
   }
 
   EIGEN_DEVICE_FUNC EIGEN_STRONG_INLINE bool isInnerChipping() const {
-    return IsInnerChipping || (static_cast<int>(Layout) == ColMajor && m_dim.actualDim() == 0) ||
-           (static_cast<int>(Layout) == RowMajor && m_dim.actualDim() == NumInputDims - 1);
+    return IsInnerChipping || m_isEffectivelyInnerChipping;
   }
 
   EIGEN_DEVICE_FUNC EIGEN_STRONG_INLINE bool isOuterChipping() const {
-    return IsOuterChipping || (static_cast<int>(Layout) == ColMajor && m_dim.actualDim() == NumInputDims - 1) ||
-           (static_cast<int>(Layout) == RowMajor && m_dim.actualDim() == 0);
+    return IsOuterChipping || m_isEffectivelyOuterChipping;
   }
 
   Dimensions m_dimensions;
@@ -352,6 +370,11 @@
   TensorEvaluator<ArgType, Device> m_impl;
   const internal::DimensionId<DimId> m_dim;
   const Device EIGEN_DEVICE_REF m_device;
+
+  // If product of all dimensions after or before the chipped dimension is `1`,
+  // it is effectively the same as chipping innermost or outermost dimension.
+  bool m_isEffectivelyInnerChipping;
+  bool m_isEffectivelyOuterChipping;
 };
 
 // Eval as lvalue