From 2918f85ba976dbfbf72f7d4c1961a577f5850148 Mon Sep 17 00:00:00 2001
From: Eugene Zhulenev <ezhulenev@google.com>
Date: Mon, 9 Dec 2019 16:19:38 -0800
Subject: Do not use std::vector in getResourceRequirements

---
 unsupported/Eigen/CXX11/src/Tensor/TensorAssign.h  |  9 ++--
 unsupported/Eigen/CXX11/src/Tensor/TensorBlock.h   | 34 --------------
 unsupported/Eigen/CXX11/src/Tensor/TensorBlockV2.h | 54 ++++++++++++++++++++++
 .../Eigen/CXX11/src/Tensor/TensorBroadcasting.h    | 13 +++---
 .../Eigen/CXX11/src/Tensor/TensorChipping.h        | 15 +++---
 .../Eigen/CXX11/src/Tensor/TensorConversion.h      |  6 +--
 unsupported/Eigen/CXX11/src/Tensor/TensorEvalTo.h  |  6 +--
 .../Eigen/CXX11/src/Tensor/TensorEvaluator.h       | 39 +++++++++-------
 .../Eigen/CXX11/src/Tensor/TensorExecutor.h        | 29 ++++--------
 .../Eigen/CXX11/src/Tensor/TensorForcedEval.h      |  6 ++-
 .../Eigen/CXX11/src/Tensor/TensorGenerator.h       | 10 ++--
 .../Eigen/CXX11/src/Tensor/TensorImagePatch.h      |  8 ----
 .../Eigen/CXX11/src/Tensor/TensorMorphing.h        | 21 ++++-----
 unsupported/Eigen/CXX11/src/Tensor/TensorPadding.h | 15 +++---
 .../Eigen/CXX11/src/Tensor/TensorReduction.h       |  9 ----
 unsupported/Eigen/CXX11/src/Tensor/TensorReverse.h | 13 +++---
 .../Eigen/CXX11/src/Tensor/TensorShuffling.h       | 17 +++----
 17 files changed, 153 insertions(+), 151 deletions(-)

diff --git a/unsupported/Eigen/CXX11/src/Tensor/TensorAssign.h b/unsupported/Eigen/CXX11/src/Tensor/TensorAssign.h
index d7795a00d..c4f6f86e8 100644
--- a/unsupported/Eigen/CXX11/src/Tensor/TensorAssign.h
+++ b/unsupported/Eigen/CXX11/src/Tensor/TensorAssign.h
@@ -208,10 +208,11 @@ struct TensorEvaluator<const TensorAssignOp<LeftArgType, RightArgType>, Device>
            TensorOpCost(0, sizeof(CoeffReturnType), 0, vectorized, PacketSize);
   }
 
-  EIGEN_DEVICE_FUNC EIGEN_STRONG_INLINE void getResourceRequirements(
-      std::vector<internal::TensorOpResourceRequirements>* resources) const {
-    m_leftImpl.getResourceRequirements(resources);
-    m_rightImpl.getResourceRequirements(resources);
+  EIGEN_DEVICE_FUNC EIGEN_STRONG_INLINE
+  internal::TensorBlockV2ResourceRequirements getResourceRequirements() const {
+    return internal::TensorBlockV2ResourceRequirements::merge(
+        m_leftImpl.getResourceRequirements(),
+        m_rightImpl.getResourceRequirements());
   }
 
   EIGEN_DEVICE_FUNC EIGEN_STRONG_INLINE void evalBlockV2(
diff --git a/unsupported/Eigen/CXX11/src/Tensor/TensorBlock.h b/unsupported/Eigen/CXX11/src/Tensor/TensorBlock.h
index 447da9121..ba11bf7a8 100644
--- a/unsupported/Eigen/CXX11/src/Tensor/TensorBlock.h
+++ b/unsupported/Eigen/CXX11/src/Tensor/TensorBlock.h
@@ -65,40 +65,6 @@ enum TensorBlockShapeType {
   kSkewedInnerDims
 };
 
-struct TensorOpResourceRequirements {
-  TensorBlockShapeType block_shape;
-  Index block_total_size;
-  // TODO(andydavis) Add 'target_num_threads' to support communication of
-  // thread-resource requirements. This will allow ops deep in the
-  // expression tree (like reductions) to communicate resources
-  // requirements based on local state (like the total number of reductions
-  // to be computed).
-  TensorOpResourceRequirements(TensorBlockShapeType shape,
-                               const Index size)
-      : block_shape(shape), block_total_size(size) {}
-};
-
-// Tries to merge multiple resource requirements.
-EIGEN_DEVICE_FUNC EIGEN_STRONG_INLINE void MergeResourceRequirements(
-    const std::vector<TensorOpResourceRequirements>& resources,
-    TensorBlockShapeType* block_shape, Index* block_total_size) {
-  if (resources.empty()) {
-    return;
-  }
-  // TODO(andydavis) Implement different policies (i.e. revert to a default
-  // policy if block shapes/sizes conflict).
-  *block_shape = resources[0].block_shape;
-  *block_total_size = resources[0].block_total_size;
-  for (std::vector<TensorOpResourceRequirements>::size_type i = 1; i < resources.size(); ++i) {
-    if (resources[i].block_shape == kSkewedInnerDims &&
-        *block_shape != kSkewedInnerDims) {
-      *block_shape = kSkewedInnerDims;
-    }
-    *block_total_size =
-        numext::maxi(*block_total_size, resources[i].block_total_size);
-  }
-}
-
 /**
  * \class TensorBlock
  * \ingroup CXX11_Tensor_Module
diff --git a/unsupported/Eigen/CXX11/src/Tensor/TensorBlockV2.h b/unsupported/Eigen/CXX11/src/Tensor/TensorBlockV2.h
index 221f8e843..6cacf1cc1 100644
--- a/unsupported/Eigen/CXX11/src/Tensor/TensorBlockV2.h
+++ b/unsupported/Eigen/CXX11/src/Tensor/TensorBlockV2.h
@@ -57,6 +57,60 @@ EIGEN_STRONG_INLINE DSizes<std::ptrdiff_t, sizeof...(Indices)> strides(
   return strides<Layout>(DSizes<std::ptrdiff_t, sizeof...(Indices)>(sizes));
 }
 
+// -------------------------------------------------------------------------- //
+
+// Tensor block shape type defines what are the shape preference for the blocks
+// extracted from the larger tensor.
+//
+// Example: blocks of 100 elements from the large 100x100 tensor:
+// - tensor: 100x100
+// - target_block_size: 100
+//
+// TensorBlockShapeType:
+//  - kUniformAllDims: 100 blocks of size 10x10
+//  - kSkewedInnerDims: 100 blocks of size 100x1 (or 1x100 depending on a column
+//                      or row major layout)
+enum class TensorBlockV2ShapeType { kUniformAllDims, kSkewedInnerDims };
+
+struct TensorBlockV2ResourceRequirements {
+  TensorBlockV2ShapeType shape_type;
+  size_t size;
+
+  TensorBlockShapeType shapeV1() const {
+    return shape_type == TensorBlockV2ShapeType::kUniformAllDims
+               ? internal::kUniformAllDims
+               : internal::kSkewedInnerDims;
+  }
+
+  static TensorBlockV2ResourceRequirements
+  merge(const TensorBlockV2ResourceRequirements &lhs,
+        const TensorBlockV2ResourceRequirements &rhs) {
+    return {merge(lhs.shape_type, rhs.shape_type), merge(rhs.size, lhs.size)};
+  }
+
+  // This is a resource requirement that should be returned from expressions
+  // that do not have any block evaluation preference (e.g. default tensor
+  // expression with raw buffer access).
+  static TensorBlockV2ResourceRequirements any() {
+    return {TensorBlockV2ShapeType::kUniformAllDims, 1};
+  }
+
+private:
+  using Requirements = TensorBlockV2ResourceRequirements;
+
+  static size_t merge(size_t lhs_size, size_t rhs_size) {
+    return numext::maxi(lhs_size, rhs_size);
+  }
+
+  static TensorBlockV2ShapeType merge(TensorBlockV2ShapeType lhs,
+                                      TensorBlockV2ShapeType rhs) {
+    return (lhs == TensorBlockV2ShapeType::kSkewedInnerDims ||
+            rhs == TensorBlockV2ShapeType::kSkewedInnerDims)
+               ? TensorBlockV2ShapeType::kSkewedInnerDims
+               : TensorBlockV2ShapeType::kUniformAllDims;
+  }
+};
+
 // -------------------------------------------------------------------------- //
 // TensorBlockDescriptor specifies a block offset within a tensor and the block
 // sizes along each of the tensor dimensions.
diff --git a/unsupported/Eigen/CXX11/src/Tensor/TensorBroadcasting.h b/unsupported/Eigen/CXX11/src/Tensor/TensorBroadcasting.h
index 80162ad12..454b0f752 100644
--- a/unsupported/Eigen/CXX11/src/Tensor/TensorBroadcasting.h
+++ b/unsupported/Eigen/CXX11/src/Tensor/TensorBroadcasting.h
@@ -616,17 +616,16 @@ struct TensorEvaluator<const TensorBroadcastingOp<Broadcast, ArgType>, Device>
            TensorOpCost(0, 0, compute_cost, vectorized, PacketSize);
   }
 
-  EIGEN_DEVICE_FUNC EIGEN_STRONG_INLINE void getResourceRequirements(
-      std::vector<internal::TensorOpResourceRequirements>* resources) const {
+  EIGEN_DEVICE_FUNC EIGEN_STRONG_INLINE
+  internal::TensorBlockV2ResourceRequirements getResourceRequirements() const {
     // TODO(wuke): Targeting L1 size is 30% faster than targeting L{-1} on large
     // tensors. But this might need further tuning.
-    Eigen::Index block_total_size_max = numext::maxi<Eigen::Index>(
+    const size_t target_block_size = numext::maxi<size_t>(
         1, m_device.firstLevelCacheSize() / sizeof(Scalar));
 
-    resources->push_back(internal::TensorOpResourceRequirements(
-        internal::kSkewedInnerDims, block_total_size_max));
-
-    m_impl.getResourceRequirements(resources);
+    return internal::TensorBlockV2ResourceRequirements::merge(
+        {internal::TensorBlockV2ShapeType::kSkewedInnerDims, target_block_size},
+        m_impl.getResourceRequirements());
   }
 
   EIGEN_DEVICE_FUNC EIGEN_STRONG_INLINE TensorBlockV2
diff --git a/unsupported/Eigen/CXX11/src/Tensor/TensorChipping.h b/unsupported/Eigen/CXX11/src/Tensor/TensorChipping.h
index 098110217..9b835c4de 100644
--- a/unsupported/Eigen/CXX11/src/Tensor/TensorChipping.h
+++ b/unsupported/Eigen/CXX11/src/Tensor/TensorChipping.h
@@ -294,13 +294,14 @@ struct TensorEvaluator<const TensorChippingOp<DimId, ArgType>, Device>
            TensorOpCost(0, 0, cost, vectorized, PacketSize);
   }
 
-  EIGEN_DEVICE_FUNC EIGEN_STRONG_INLINE void getResourceRequirements(
-      std::vector<internal::TensorOpResourceRequirements>* resources) const {
-    Eigen::Index block_total_size_max = numext::maxi<Eigen::Index>(
-        1, m_device.lastLevelCacheSize() / sizeof(Scalar));
-    resources->push_back(internal::TensorOpResourceRequirements(
-        internal::kSkewedInnerDims, block_total_size_max));
-    m_impl.getResourceRequirements(resources);
+  EIGEN_DEVICE_FUNC EIGEN_STRONG_INLINE
+  internal::TensorBlockV2ResourceRequirements getResourceRequirements() const {
+    const size_t target_block_size =
+        numext::maxi<size_t>(1, m_device.lastLevelCacheSize() / sizeof(Scalar));
+
+    return internal::TensorBlockV2ResourceRequirements::merge(
+        {internal::TensorBlockV2ShapeType::kSkewedInnerDims, target_block_size},
+        m_impl.getResourceRequirements());
   }
 
   EIGEN_DEVICE_FUNC EIGEN_STRONG_INLINE TensorBlockV2
diff --git a/unsupported/Eigen/CXX11/src/Tensor/TensorConversion.h b/unsupported/Eigen/CXX11/src/Tensor/TensorConversion.h
index 027322582..f9f90ec02 100644
--- a/unsupported/Eigen/CXX11/src/Tensor/TensorConversion.h
+++ b/unsupported/Eigen/CXX11/src/Tensor/TensorConversion.h
@@ -397,9 +397,9 @@ struct TensorEvaluator<const TensorConversionOp<TargetType, ArgType>, Device>
     }
   }
 
-  EIGEN_DEVICE_FUNC EIGEN_STRONG_INLINE void getResourceRequirements(
-      std::vector<internal::TensorOpResourceRequirements>* resources) const {
-    m_impl.getResourceRequirements(resources);
+  EIGEN_DEVICE_FUNC EIGEN_STRONG_INLINE
+  internal::TensorBlockV2ResourceRequirements getResourceRequirements() const {
+    return m_impl.getResourceRequirements();
   }
 
   EIGEN_DEVICE_FUNC EIGEN_STRONG_INLINE TensorBlockV2
diff --git a/unsupported/Eigen/CXX11/src/Tensor/TensorEvalTo.h b/unsupported/Eigen/CXX11/src/Tensor/TensorEvalTo.h
index e6bb56136..2cbc4e878 100644
--- a/unsupported/Eigen/CXX11/src/Tensor/TensorEvalTo.h
+++ b/unsupported/Eigen/CXX11/src/Tensor/TensorEvalTo.h
@@ -164,9 +164,9 @@ struct TensorEvaluator<const TensorEvalToOp<ArgType, MakePointer_>, Device>
     internal::pstoret<CoeffReturnType, PacketReturnType, Aligned>(m_buffer + i, m_impl.template packet<TensorEvaluator<ArgType, Device>::IsAligned ? Aligned : Unaligned>(i));
   }
 
-  EIGEN_DEVICE_FUNC EIGEN_STRONG_INLINE void getResourceRequirements(
-      std::vector<internal::TensorOpResourceRequirements>* resources) const {
-    m_impl.getResourceRequirements(resources);
+  EIGEN_DEVICE_FUNC EIGEN_STRONG_INLINE
+  internal::TensorBlockV2ResourceRequirements getResourceRequirements() const {
+    return m_impl.getResourceRequirements();
   }
 
   EIGEN_DEVICE_FUNC EIGEN_STRONG_INLINE void evalBlockV2(
diff --git a/unsupported/Eigen/CXX11/src/Tensor/TensorEvaluator.h b/unsupported/Eigen/CXX11/src/Tensor/TensorEvaluator.h
index c0314499d..4085ad314 100644
--- a/unsupported/Eigen/CXX11/src/Tensor/TensorEvaluator.h
+++ b/unsupported/Eigen/CXX11/src/Tensor/TensorEvaluator.h
@@ -149,8 +149,10 @@ struct TensorEvaluator
                         PacketType<CoeffReturnType, Device>::size);
   }
 
-  EIGEN_DEVICE_FUNC EIGEN_STRONG_INLINE void getResourceRequirements(
-      std::vector<internal::TensorOpResourceRequirements>*) const {}
+  EIGEN_DEVICE_FUNC EIGEN_STRONG_INLINE
+  internal::TensorBlockV2ResourceRequirements getResourceRequirements() const {
+    return internal::TensorBlockV2ResourceRequirements::any();
+  }
 
   EIGEN_DEVICE_FUNC EIGEN_STRONG_INLINE TensorBlockV2
   blockV2(TensorBlockDesc& desc, TensorBlockScratch& scratch,
@@ -320,8 +322,10 @@ struct TensorEvaluator<const Derived, Device>
                         PacketType<CoeffReturnType, Device>::size);
   }
 
-  EIGEN_DEVICE_FUNC EIGEN_STRONG_INLINE void getResourceRequirements(
-      std::vector<internal::TensorOpResourceRequirements>*) const {}
+  EIGEN_DEVICE_FUNC EIGEN_STRONG_INLINE
+  internal::TensorBlockV2ResourceRequirements getResourceRequirements() const {
+    return internal::TensorBlockV2ResourceRequirements::any();
+  }
 
   EIGEN_DEVICE_FUNC EIGEN_STRONG_INLINE TensorBlockV2
   blockV2(TensorBlockDesc& desc, TensorBlockScratch& scratch,
@@ -517,9 +521,9 @@ struct TensorEvaluator<const TensorCwiseUnaryOp<UnaryOp, ArgType>, Device>
         TensorOpCost(0, 0, functor_cost, vectorized, PacketSize);
   }
 
-  EIGEN_DEVICE_FUNC EIGEN_STRONG_INLINE void getResourceRequirements(
-      std::vector<internal::TensorOpResourceRequirements>* resources) const {
-    m_argImpl.getResourceRequirements(resources);
+  EIGEN_DEVICE_FUNC EIGEN_STRONG_INLINE
+  internal::TensorBlockV2ResourceRequirements getResourceRequirements() const {
+    return m_argImpl.getResourceRequirements();
   }
 
   EIGEN_DEVICE_FUNC EIGEN_STRONG_INLINE TensorBlockV2
@@ -655,10 +659,11 @@ struct TensorEvaluator<const TensorCwiseBinaryOp<BinaryOp, LeftArgType, RightArg
            TensorOpCost(0, 0, functor_cost, vectorized, PacketSize);
   }
 
-  EIGEN_DEVICE_FUNC EIGEN_STRONG_INLINE void getResourceRequirements(
-      std::vector<internal::TensorOpResourceRequirements>* resources) const {
-    m_leftImpl.getResourceRequirements(resources);
-    m_rightImpl.getResourceRequirements(resources);
+  EIGEN_DEVICE_FUNC EIGEN_STRONG_INLINE
+  internal::TensorBlockV2ResourceRequirements getResourceRequirements() const {
+    return internal::TensorBlockV2ResourceRequirements::merge(
+        m_leftImpl.getResourceRequirements(),
+        m_rightImpl.getResourceRequirements());
   }
 
   EIGEN_DEVICE_FUNC EIGEN_STRONG_INLINE TensorBlockV2
@@ -934,11 +939,13 @@ struct TensorEvaluator<const TensorSelectOp<IfArgType, ThenArgType, ElseArgType>
         .cwiseMax(m_elseImpl.costPerCoeff(vectorized));
   }
 
-  EIGEN_DEVICE_FUNC EIGEN_STRONG_INLINE void getResourceRequirements(
-      std::vector<internal::TensorOpResourceRequirements>* resources) const {
-    m_condImpl.getResourceRequirements(resources);
-    m_thenImpl.getResourceRequirements(resources);
-    m_elseImpl.getResourceRequirements(resources);
+  EIGEN_DEVICE_FUNC EIGEN_STRONG_INLINE
+  internal::TensorBlockV2ResourceRequirements getResourceRequirements() const {
+    return internal::TensorBlockV2ResourceRequirements::merge(
+        m_condImpl.getResourceRequirements(),
+        internal::TensorBlockV2ResourceRequirements::merge(
+            m_thenImpl.getResourceRequirements(),
+            m_elseImpl.getResourceRequirements()));
   }
 
   EIGEN_DEVICE_FUNC EIGEN_STRONG_INLINE TensorBlockV2
diff --git a/unsupported/Eigen/CXX11/src/Tensor/TensorExecutor.h b/unsupported/Eigen/CXX11/src/Tensor/TensorExecutor.h
index ca056e96e..db123d8a4 100644
--- a/unsupported/Eigen/CXX11/src/Tensor/TensorExecutor.h
+++ b/unsupported/Eigen/CXX11/src/Tensor/TensorExecutor.h
@@ -182,25 +182,18 @@ class TensorExecutor<Expression, DefaultDevice, Vectorizable,
         TensorBlockScratch;
 
     Evaluator evaluator(expr, device);
-    Index total_size = array_prod(evaluator.dimensions());
-    Index cache_size = device.firstLevelCacheSize() / sizeof(Scalar);
 
     // TODO(ezhulenev): Do not use tiling for small tensors?
     const bool needs_assign = evaluator.evalSubExprsIfNeeded(NULL);
 
     if (needs_assign) {
-      // Size tensor blocks to fit in cache (or requested target block size).
-      Index block_total_size = numext::mini(cache_size, total_size);
-      TensorBlockShapeType block_shape = kSkewedInnerDims;
       // Query expression tree for desired block size/shape.
-      std::vector<TensorOpResourceRequirements> resources;
-      evaluator.getResourceRequirements(&resources);
-      MergeResourceRequirements(resources, &block_shape, &block_total_size);
+      const TensorBlockV2ResourceRequirements requirements =
+          evaluator.getResourceRequirements();
 
-      TensorBlockMapper block_mapper(
-          TensorBlockDimensions(evaluator.dimensions()), block_shape,
-          block_total_size);
-      block_total_size = block_mapper.block_dims_total_size();
+      const TensorBlockMapper block_mapper(
+          TensorBlockDimensions(evaluator.dimensions()), requirements.shapeV1(),
+          requirements.size);
 
       // Share scratch memory allocator between all blocks.
       TensorBlockScratch scratch(device);
@@ -268,14 +261,10 @@ template <typename Evaluator, typename TensorBlockMapper, bool Vectorizable>
 TensorExecutorTilingContext<TensorBlockMapper> GetTensorExecutorTilingContext(
     const ThreadPoolDevice& device, const Evaluator& evaluator,
     bool allocate_buffer = true) {
-  // Prefer blocks skewed toward inner dimension.
-  TensorBlockShapeType block_shape = kSkewedInnerDims;
-  Index block_total_size = 0;
-
   // Query expression tree for desired block size/shape.
-  std::vector<TensorOpResourceRequirements> resources;
-  evaluator.getResourceRequirements(&resources);
-  MergeResourceRequirements(resources, &block_shape, &block_total_size);
+  const TensorBlockV2ResourceRequirements requirements =
+      evaluator.getResourceRequirements();
+
   int num_threads = device.numThreads();
 
   // Estimate minimum block size based on cost.
@@ -285,7 +274,7 @@ TensorExecutorTilingContext<TensorBlockMapper> GetTensorExecutorTilingContext(
 
   TensorBlockMapper block_mapper(
       typename TensorBlockMapper::Dimensions(evaluator.dimensions()),
-      block_shape, block_size);
+      requirements.shapeV1(), block_size);
 
   block_size = block_mapper.block_dims_total_size();
   const size_t align = numext::maxi(EIGEN_MAX_ALIGN_BYTES, 1);
diff --git a/unsupported/Eigen/CXX11/src/Tensor/TensorForcedEval.h b/unsupported/Eigen/CXX11/src/Tensor/TensorForcedEval.h
index 8d17d4b76..95fa4f509 100644
--- a/unsupported/Eigen/CXX11/src/Tensor/TensorForcedEval.h
+++ b/unsupported/Eigen/CXX11/src/Tensor/TensorForcedEval.h
@@ -176,8 +176,10 @@ struct TensorEvaluator<const TensorForcedEvalOp<ArgType_>, Device>
     return internal::ploadt<PacketReturnType, LoadMode>(m_buffer + index);
   }
 
-  EIGEN_DEVICE_FUNC EIGEN_STRONG_INLINE void getResourceRequirements(
-      std::vector<internal::TensorOpResourceRequirements>*) const {}
+  EIGEN_DEVICE_FUNC EIGEN_STRONG_INLINE
+  internal::TensorBlockV2ResourceRequirements getResourceRequirements() const {
+    return internal::TensorBlockV2ResourceRequirements::any();
+  }
 
   EIGEN_DEVICE_FUNC EIGEN_STRONG_INLINE TensorBlockV2
   blockV2(TensorBlockDesc& desc, TensorBlockScratch& scratch,
diff --git a/unsupported/Eigen/CXX11/src/Tensor/TensorGenerator.h b/unsupported/Eigen/CXX11/src/Tensor/TensorGenerator.h
index 77fa32dc7..bed7a1b00 100644
--- a/unsupported/Eigen/CXX11/src/Tensor/TensorGenerator.h
+++ b/unsupported/Eigen/CXX11/src/Tensor/TensorGenerator.h
@@ -167,12 +167,12 @@ struct TensorEvaluator<const TensorGeneratorOp<Generator, ArgType>, Device>
     return rslt;
   }
 
-  EIGEN_DEVICE_FUNC EIGEN_STRONG_INLINE void getResourceRequirements(
-      std::vector<internal::TensorOpResourceRequirements>* resources) const {
-    Eigen::Index block_total_size_max = numext::maxi<Eigen::Index>(
+  EIGEN_DEVICE_FUNC EIGEN_STRONG_INLINE
+  internal::TensorBlockV2ResourceRequirements getResourceRequirements() const {
+    const size_t target_block_size = numext::maxi<size_t>(
         1, m_device.firstLevelCacheSize() / sizeof(Scalar));
-    resources->push_back(internal::TensorOpResourceRequirements(
-        internal::kSkewedInnerDims, block_total_size_max));
+    return {internal::TensorBlockV2ShapeType::kSkewedInnerDims,
+            target_block_size};
   }
 
   struct BlockIteratorState {
diff --git a/unsupported/Eigen/CXX11/src/Tensor/TensorImagePatch.h b/unsupported/Eigen/CXX11/src/Tensor/TensorImagePatch.h
index 76bed5526..959e77e01 100644
--- a/unsupported/Eigen/CXX11/src/Tensor/TensorImagePatch.h
+++ b/unsupported/Eigen/CXX11/src/Tensor/TensorImagePatch.h
@@ -540,14 +540,6 @@ struct TensorEvaluator<const TensorImagePatchOp<Rows, Cols, ArgType>, Device>
            TensorOpCost(0, 0, compute_cost, vectorized, PacketSize);
   }
 
-  EIGEN_DEVICE_FUNC EIGEN_STRONG_INLINE void getResourceRequirements(
-      std::vector<internal::TensorOpResourceRequirements>* resources) const {
-    Eigen::Index block_total_size_max = numext::maxi<Eigen::Index>(
-        1, m_device.lastLevelCacheSize() / sizeof(Scalar));
-    resources->push_back(internal::TensorOpResourceRequirements(
-        internal::kSkewedInnerDims, block_total_size_max));
-  }
-
  protected:
   EIGEN_DEVICE_FUNC EIGEN_STRONG_INLINE PacketReturnType packetWithPossibleZero(Index index) const
   {
diff --git a/unsupported/Eigen/CXX11/src/Tensor/TensorMorphing.h b/unsupported/Eigen/CXX11/src/Tensor/TensorMorphing.h
index d3628f94e..7299cdcdb 100644
--- a/unsupported/Eigen/CXX11/src/Tensor/TensorMorphing.h
+++ b/unsupported/Eigen/CXX11/src/Tensor/TensorMorphing.h
@@ -198,10 +198,9 @@ struct TensorEvaluator<const TensorReshapingOp<NewDimensions, ArgType>, Device>
     return m_impl.costPerCoeff(vectorized);
   }
 
-  EIGEN_DEVICE_FUNC EIGEN_STRONG_INLINE void getResourceRequirements(
-      std::vector<internal::TensorOpResourceRequirements>*) const {
-    // TODO(ezhulenev): If we'll ever support block evaluation without raw
-    // access we'll need to get requirements from `m_impl`.
+  EIGEN_DEVICE_FUNC EIGEN_STRONG_INLINE
+  internal::TensorBlockV2ResourceRequirements getResourceRequirements() const {
+    return internal::TensorBlockV2ResourceRequirements::any();
   }
 
   // required in block(OutputTensorBlock* output_block) const
@@ -636,13 +635,13 @@ struct TensorEvaluator<const TensorSlicingOp<StartIndices, Sizes, ArgType>, Devi
     return m_impl.costPerCoeff(vectorized) + TensorOpCost(0, 0, m_is_identity ? 1 : NumDims);
   }
 
-  EIGEN_DEVICE_FUNC EIGEN_STRONG_INLINE void getResourceRequirements(
-      std::vector<internal::TensorOpResourceRequirements>* resources) const {
-    Eigen::Index block_total_size_max = numext::maxi<Eigen::Index>(
-        1, m_device.lastLevelCacheSize() / sizeof(Scalar));
-    resources->push_back(internal::TensorOpResourceRequirements(
-        internal::kSkewedInnerDims, block_total_size_max));
-    m_impl.getResourceRequirements(resources);
+  EIGEN_DEVICE_FUNC EIGEN_STRONG_INLINE
+  internal::TensorBlockV2ResourceRequirements getResourceRequirements() const {
+    const size_t target_block_size =
+        numext::maxi<size_t>(1, m_device.lastLevelCacheSize() / sizeof(Scalar));
+    return internal::TensorBlockV2ResourceRequirements::merge(
+        {internal::TensorBlockV2ShapeType::kSkewedInnerDims, target_block_size},
+        m_impl.getResourceRequirements());
   }
 
   EIGEN_DEVICE_FUNC EIGEN_STRONG_INLINE TensorBlockV2
diff --git a/unsupported/Eigen/CXX11/src/Tensor/TensorPadding.h b/unsupported/Eigen/CXX11/src/Tensor/TensorPadding.h
index 4d1a09ada..0d7444730 100644
--- a/unsupported/Eigen/CXX11/src/Tensor/TensorPadding.h
+++ b/unsupported/Eigen/CXX11/src/Tensor/TensorPadding.h
@@ -227,14 +227,13 @@ struct TensorEvaluator<const TensorPaddingOp<PaddingDimensions, ArgType>, Device
     return cost;
   }
 
-  EIGEN_DEVICE_FUNC EIGEN_STRONG_INLINE void getResourceRequirements(
-      std::vector<internal::TensorOpResourceRequirements>* resources) const {
-    Eigen::Index block_total_size_max = numext::maxi<Eigen::Index>(
-        1, m_device.lastLevelCacheSize() / sizeof(Scalar));
-    resources->push_back(internal::TensorOpResourceRequirements(
-        internal::kSkewedInnerDims, block_total_size_max));
-
-    m_impl.getResourceRequirements(resources);
+  EIGEN_DEVICE_FUNC EIGEN_STRONG_INLINE
+  internal::TensorBlockV2ResourceRequirements getResourceRequirements() const {
+    const size_t target_block_size =
+        numext::maxi<size_t>(1, m_device.lastLevelCacheSize() / sizeof(Scalar));
+    return internal::TensorBlockV2ResourceRequirements::merge(
+        {internal::TensorBlockV2ShapeType::kSkewedInnerDims, target_block_size},
+        m_impl.getResourceRequirements());
   }
 
   EIGEN_DEVICE_FUNC EIGEN_STRONG_INLINE TensorBlockV2
diff --git a/unsupported/Eigen/CXX11/src/Tensor/TensorReduction.h b/unsupported/Eigen/CXX11/src/Tensor/TensorReduction.h
index 0bb1e643e..c600c319d 100644
--- a/unsupported/Eigen/CXX11/src/Tensor/TensorReduction.h
+++ b/unsupported/Eigen/CXX11/src/Tensor/TensorReduction.h
@@ -905,15 +905,6 @@ struct TensorReductionEvaluatorBase<const TensorReductionOp<Op, Dims, ArgType, M
     }
   }
 
-  EIGEN_DEVICE_FUNC EIGEN_STRONG_INLINE void getResourceRequirements(
-      std::vector<internal::TensorOpResourceRequirements>* resources) const {
-    Eigen::Index block_total_size_max = numext::maxi<Eigen::Index>(
-        1, m_device.lastLevelCacheSize() / sizeof(Scalar));
-    resources->push_back(internal::TensorOpResourceRequirements(
-        internal::kSkewedInnerDims, block_total_size_max));
-    m_impl.getResourceRequirements(resources);
-  }
-
   EIGEN_DEVICE_FUNC EvaluatorPointerType data() const { return m_result; }
   EIGEN_DEVICE_FUNC const TensorEvaluator<ArgType, Device>& impl() const { return m_impl; }
   EIGEN_DEVICE_FUNC const Device& device() const { return m_device; }
diff --git a/unsupported/Eigen/CXX11/src/Tensor/TensorReverse.h b/unsupported/Eigen/CXX11/src/Tensor/TensorReverse.h
index c5830da0a..0d18cfc36 100644
--- a/unsupported/Eigen/CXX11/src/Tensor/TensorReverse.h
+++ b/unsupported/Eigen/CXX11/src/Tensor/TensorReverse.h
@@ -248,12 +248,13 @@ struct TensorEvaluator<const TensorReverseOp<ReverseDimensions, ArgType>, Device
     return rslt;
   }
 
-  EIGEN_DEVICE_FUNC EIGEN_STRONG_INLINE void getResourceRequirements(
-      std::vector<internal::TensorOpResourceRequirements>* resources) const {
-    Eigen::Index block_total_size_max = numext::maxi<Eigen::Index>(
-        1, m_device.lastLevelCacheSize() / sizeof(Scalar));
-    resources->push_back(internal::TensorOpResourceRequirements(
-        internal::kSkewedInnerDims, block_total_size_max));
+  EIGEN_DEVICE_FUNC EIGEN_STRONG_INLINE
+  internal::TensorBlockV2ResourceRequirements getResourceRequirements() const {
+    const size_t target_block_size =
+        numext::maxi<size_t>(1, m_device.lastLevelCacheSize() / sizeof(Scalar));
+    return internal::TensorBlockV2ResourceRequirements::merge(
+        {internal::TensorBlockV2ShapeType::kSkewedInnerDims, target_block_size},
+        m_impl.getResourceRequirements());
   }
 
   EIGEN_DEVICE_FUNC EIGEN_STRONG_INLINE TensorBlockV2
diff --git a/unsupported/Eigen/CXX11/src/Tensor/TensorShuffling.h b/unsupported/Eigen/CXX11/src/Tensor/TensorShuffling.h
index 655fd91e8..42bca8172 100644
--- a/unsupported/Eigen/CXX11/src/Tensor/TensorShuffling.h
+++ b/unsupported/Eigen/CXX11/src/Tensor/TensorShuffling.h
@@ -244,18 +244,19 @@ struct TensorEvaluator<const TensorShufflingOp<Shuffle, ArgType>, Device>
     return PacketLoader<LoadMode, Self, TensorEvaluator<ArgType, Device>::PacketAccess>::Run(*this, index);
   }
 
-  EIGEN_DEVICE_FUNC EIGEN_STRONG_INLINE void getResourceRequirements(
-      std::vector<internal::TensorOpResourceRequirements>* resources) const {
+  EIGEN_DEVICE_FUNC EIGEN_STRONG_INLINE
+  internal::TensorBlockV2ResourceRequirements getResourceRequirements() const {
     static const int inner_dim =
         Layout == static_cast<int>(ColMajor) ? 0 : NumDims - 1;
-    const bool inner_dim_shuffled = m_shuffle[inner_dim] != inner_dim;
 
-    Eigen::Index block_total_size_max = numext::maxi<Eigen::Index>(
+    const size_t target_block_size = numext::maxi<size_t>(
         1, m_device.firstLevelCacheSize() / sizeof(Scalar));
-    resources->push_back(internal::TensorOpResourceRequirements(
-        inner_dim_shuffled ? internal::kUniformAllDims
-                           : internal::kSkewedInnerDims,
-        block_total_size_max));
+
+    const bool inner_dim_shuffled = m_shuffle[inner_dim] != inner_dim;
+    return {inner_dim_shuffled
+                ? internal::TensorBlockV2ShapeType::kUniformAllDims
+                : internal::TensorBlockV2ShapeType::kSkewedInnerDims,
+            target_block_size};
   }
 
   EIGEN_DEVICE_FUNC EIGEN_STRONG_INLINE TensorBlockV2
-- 
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