COMPMID-1995: Prepare Graph to support different input/output quantization info

- Added support for different input/output qinfo in ActivationLayer and DepthwiseConv
- Added support for different input/output qinfo in ConcatenateLayer introducing ConcatDescriptor
- Added reshape validate
- Allow OutputLayer to return a specific connection index from the input
- Not run Inplace and Depth mutator when input/output quantization info are different

Change-Id: I03f5e416fc43ddd284e1501887202a3145f76d8a
Signed-off-by: Isabella Gottardi <isabella.gottardi@arm.com>
Reviewed-on: https://review.mlplatform.org/c/852
Comments-Addressed: Arm Jenkins <bsgcomp@arm.com>
Tested-by: Arm Jenkins <bsgcomp@arm.com>
Reviewed-by: Michele Di Giorgio <michele.digiorgio@arm.com>
Reviewed-by: Georgios Pinitas <georgios.pinitas@arm.com>
diff --git a/src/graph/mutators/DepthConcatSubTensorMutator.cpp b/src/graph/mutators/DepthConcatSubTensorMutator.cpp
index a170c4d..0e0a26b 100644
--- a/src/graph/mutators/DepthConcatSubTensorMutator.cpp
+++ b/src/graph/mutators/DepthConcatSubTensorMutator.cpp
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2018 ARM Limited.
+ * Copyright (c) 2018-2019 ARM Limited.
  *
  * SPDX-License-Identifier: MIT
  *
@@ -69,11 +69,12 @@
                 continue;
             }
 
-            // Check that all tensor have the same target and valid inputs
+            // Check that all tensor have the same target, valid inputs and same quantization info
             bool is_valid = std::all_of(node->input_edges().cbegin(), node->input_edges().cend(),
                                         [&](const EdgeID & eid)
             {
-                return (g.edge(eid) != nullptr) && (g.edge(eid)->tensor() != nullptr) && (g.edge(eid)->tensor()->desc().target == output_tensor->desc().target);
+                return (g.edge(eid) != nullptr) && (g.edge(eid)->tensor() != nullptr) && (g.edge(eid)->tensor()->desc().target == output_tensor->desc().target)
+                       && (g.edge(eid)->tensor()->desc().quant_info == output_tensor->desc().quant_info);
             });
 
             // Create subtensors
diff --git a/src/graph/mutators/InPlaceOperationMutator.cpp b/src/graph/mutators/InPlaceOperationMutator.cpp
index 31921b3..1c2985d 100644
--- a/src/graph/mutators/InPlaceOperationMutator.cpp
+++ b/src/graph/mutators/InPlaceOperationMutator.cpp
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2018 ARM Limited.
+ * Copyright (c) 2018-2019 ARM Limited.
  *
  * SPDX-License-Identifier: MIT
  *
@@ -56,8 +56,8 @@
 
                 ARM_COMPUTE_ERROR_ON(current_output_tensor == nullptr || new_output_tensor == nullptr);
 
-                // Prevent in-place operation if there is an accessor bound to the in-place tensor
-                if(new_output_tensor->accessor() == nullptr)
+                // Prevent in-place operation if there is an accessor bound to the in-place tensor or quantization info are different
+                if(new_output_tensor->accessor() == nullptr || current_output_tensor->desc().quant_info == new_output_tensor->desc().quant_info)
                 {
                     ARM_COMPUTE_LOG_GRAPH_VERBOSE("Switching to in-place computation for the node with ID : "
                                                   << node->id() << " and name : " << node->name() << std::endl);
diff --git a/src/graph/mutators/NodeFusionMutator.cpp b/src/graph/mutators/NodeFusionMutator.cpp
index 5927a59..724307e 100644
--- a/src/graph/mutators/NodeFusionMutator.cpp
+++ b/src/graph/mutators/NodeFusionMutator.cpp
@@ -211,10 +211,17 @@
     {
         return true;
     };
-    auto qs8_prec = [](INode & n)
+    auto qs8_prec = [&g](INode & n)
     {
         ARM_COMPUTE_ERROR_ON(n.output(0) == nullptr);
-        return n.output(0)->desc().data_type == DataType::QASYMM8;
+
+        const auto output_edge_id = *n.output_edges().begin();
+        const auto output_edge    = g.edge(output_edge_id);
+        // To perform fusion the two nodes must have same output quantization information
+        const bool same_qinfo     = n.output(0)->desc().quant_info == output_edge->producer()->output(0)->desc().quant_info;
+        const bool output_qasymm8 = n.output(0)->desc().data_type == DataType::QASYMM8;
+
+        return output_qasymm8 && same_qinfo;
     };
 
     // Fusion mutations