Fix fully connected and matmul mismatches

* There is an issue with quantized fully connected and matmul
  when the lower bound of bounded ReLU is negative.
* Use int32_t for the calculation of min/max quantized value
  rather than PixelValue to avoid this issue.

Partially resolves: COMPMID-5996
Signed-off-by: Viet-Hoa Do <viet-hoa.do@arm.com>
Change-Id: I7b22e9d56a2441fc6a4c5c4e627f57d6e00d6ff1
Reviewed-on: https://review.mlplatform.org/c/ml/ComputeLibrary/+/9502
Tested-by: Arm Jenkins <bsgcomp@arm.com>
Reviewed-by: Jakub Sujak <jakub.sujak@arm.com>
Comments-Addressed: Arm Jenkins <bsgcomp@arm.com>
Benchmark: Arm Jenkins <bsgcomp@arm.com>
diff --git a/src/core/utils/quantization/AsymmHelpers.cpp b/src/core/utils/quantization/AsymmHelpers.cpp
index ba9a97a..f5b69c7 100644
--- a/src/core/utils/quantization/AsymmHelpers.cpp
+++ b/src/core/utils/quantization/AsymmHelpers.cpp
@@ -24,6 +24,7 @@
 #include "arm_compute/core/utils/quantization/AsymmHelpers.h"
 #include "arm_compute/core/Helpers.h"
 #include "support/ToolchainSupport.h"
+#include "src/core/utils/quantization/AsymmHelpers.h"
 
 #include <cmath>
 #include <limits>
@@ -177,11 +178,15 @@
     return std::make_pair(min_quant_val, max_quant_val);
 }
 
-std::tuple<PixelValue, PixelValue> get_quantized_asymmetric_output_min_max(const QuantizationInfo &q_info, const ActivationLayerInfo &act_info, DataType data_type)
+std::tuple<int32_t, int32_t> get_quantized_asymmetric_output_min_max(const QuantizationInfo &q_info, const ActivationLayerInfo &act_info, DataType data_type)
 {
-    PixelValue type_min{};
-    PixelValue type_max{};
-    std::tie(type_min, type_max)         = get_min_max(data_type);
+    ARM_COMPUTE_ERROR_ON(data_type != DataType::QASYMM8 && data_type != DataType::QASYMM8_SIGNED);
+
+    const auto min_max = get_min_max(data_type);
+
+    int32_t type_min = std::get<0>(min_max).get<int32_t>();
+    int32_t type_max = std::get<1>(min_max).get<int32_t>();
+
     const UniformQuantizationInfo q_unif = q_info.uniform();
 
     if(act_info.enabled())
@@ -189,15 +194,15 @@
         switch(act_info.activation())
         {
             case ActivationLayerInfo::ActivationFunction::RELU:
-                type_min = PixelValue(q_unif.offset);
+                type_min = q_unif.offset;
                 break;
             case ActivationLayerInfo::ActivationFunction::BOUNDED_RELU:
-                type_min = PixelValue(q_unif.offset);
-                type_max = PixelValue(act_info.a(), data_type, q_info);
+                type_min = q_unif.offset;
+                type_max = (data_type == DataType::QASYMM8) ? quantize_qasymm8(act_info.a(), q_info) : quantize_qasymm8_signed(act_info.a(), q_info);
                 break;
             case ActivationLayerInfo::ActivationFunction::LU_BOUNDED_RELU:
-                type_min = PixelValue(act_info.b(), data_type, q_info);
-                type_max = PixelValue(act_info.a(), data_type, q_info);
+                type_min = (data_type == DataType::QASYMM8) ? quantize_qasymm8(act_info.b(), q_info) : quantize_qasymm8_signed(act_info.b(), q_info);
+                type_max = (data_type == DataType::QASYMM8) ? quantize_qasymm8(act_info.a(), q_info) : quantize_qasymm8_signed(act_info.a(), q_info);
                 break;
             default:
                 ARM_COMPUTE_ERROR("Activation function not supported.");
@@ -205,7 +210,7 @@
         }
     }
 
-    return std::make_pair(type_min, type_max);
+    return std::make_tuple(type_min, type_max);
 }
 
 void compute_quantized_multipliers_and_shifts(const ITensorInfo *input,