IVGCVSW-4139 Fix regression in ConvertDequantize()

* Removed TENSOR_QUANT8_SYMM from the list of generally supported
  tensor data types
* Fixed tensor info in DequantizeIfRequired() for on the fly
  dequantized QSymm8 weights
* Moved code for checking whether a Dequantize operator is linked
  to FullyConnected or Lstm weights from ConvertDequantize() into
  a separate function inside 1.2/HalPolicy.cpp

Signed-off-by: Aron Virginas-Tar <Aron.Virginas-Tar@arm.com>
Change-Id: I19ea6f89a90f553a964b87d44f8ad8a064e96f7f

1 files changed, 65 insertions, 0 deletions

diff --git a/1.2/HalPolicy.cpp b/1.2/HalPolicy.cpp
index f901a31b..c8e29688 100644
--- a/1.2/HalPolicy.cpp
+++ b/1.2/HalPolicy.cpp
@@ -23,6 +23,63 @@ namespace hal_1_2
 
 using namespace armnn;
 
+namespace
+{
+
+bool IsQSymmDequantizeForWeights(const Operation& operation, const Model& model)
+{
+    const Operand* operand = GetInputOperand<hal_1_2::HalPolicy>(operation, 0, model);
+    if (!operand)
+    {
+        return false;
+    }
+
+    if(!IsQSymm8(*operand))
+    {
+        // Only QSymm8 weights are dequantized on the fly by the driver
+        return false;
+    }
+
+    if (!IsOperandConstant<hal_1_2::HalPolicy>(*operand))
+    {
+        // Non-const input is not accepted for weights
+        return false;
+    }
+
+    // Iterate through all the operations and find the operation feeding from the Dequantize output
+    const size_t outputIndex = operation.outputs[0];
+    for (uint32_t operationIdx = 0; operationIdx < model.operations.size(); ++operationIdx)
+    {
+        const auto& operationIt = model.operations[operationIdx];
+        switch (operationIt.type)
+        {
+            case HalPolicy::OperationType::FULLY_CONNECTED:
+                if (outputIndex == operationIt.inputs[1]) // Weights are bound to slot 1
+                {
+                    // If the output is going into the FC weights return true
+                    return true;
+                }
+                break;
+            case HalPolicy::OperationType::LSTM:
+                for (size_t k = 0; k < operationIt.inputs.size(); ++k)
+                {
+                    if (outputIndex == operationIt.inputs[k])
+                    {
+                        // If the output is going into the LSTM weights return true
+                        return true;
+                    }
+                }
+                break;
+            default:
+                break;
+        }
+    }
+
+    return false;
+}
+
+} // anonymous namespace
+
 bool HalPolicy::ConvertOperation(const Operation& operation, const Model& model, ConversionData& data)
 {
     switch (operation.type)
@@ -561,6 +618,14 @@ bool HalPolicy::ConvertDepthwiseConv2d(const Operation& operation, const Model&
 bool HalPolicy::ConvertDequantize(const Operation& operation, const Model& model, ConversionData& data)
 {
     ALOGV("hal_1_2::HalPolicy::ConvertDequantize()");
+
+    if (IsQSymmDequantizeForWeights(operation, model))
+    {
+        // NOTE: QSymm8 weights are dequantized internally by the driver,
+        // therefore this type of Dequantize is implicitly supported
+        return true;
+    }
+
     return ::ConvertDequantize<hal_1_2::HalPolicy>(operation, model, data);
 }