Add LUT for quantized sigmoid function

* Move LUT implementation to a seperate file. It will be used
  for both QASYMM8 and QASYMM8_SIGNED.
* Fix wrong constant value related to QASYMM8_SIGNED leaky ReLU
  in 32-bit build.

Resolves: COMPMID-5464
Signed-off-by: Viet-Hoa Do <viet-hoa.do@arm.com>
Change-Id: I2b24d52409a38f1b66fd532f431eff8a9e4547b6
Reviewed-on: https://review.mlplatform.org/c/ml/ComputeLibrary/+/8066
Comments-Addressed: Arm Jenkins <bsgcomp@arm.com>
Reviewed-by: Gunes Bayir <gunes.bayir@arm.com>
Tested-by: Arm Jenkins <bsgcomp@arm.com>
Benchmark: Arm Jenkins <bsgcomp@arm.com>
diff --git a/arm_compute/core/Types.h b/arm_compute/core/Types.h
index 952c174..1fad815 100644
--- a/arm_compute/core/Types.h
+++ b/arm_compute/core/Types.h
@@ -1686,7 +1686,7 @@
         return _lut;
     }
 
-    void init_lut(const UniformQuantizationInfo &qi_in, const UniformQuantizationInfo &qi_out)
+    void init_lut(DataType data_type, const UniformQuantizationInfo &qi_in, const UniformQuantizationInfo &qi_out)
     {
         if(_act == ActivationFunction::HARD_SWISH)
         {
@@ -1696,14 +1696,35 @@
         {
             qasymm8_leaky_relu_populate_table(_lut, qi_in, qi_out, _a);
         }
+        else if(_act == ActivationFunction::LOGISTIC)
+        {
+            if(data_type == DataType::QASYMM8)
+            {
+                qasymm8_logistic_populate_table(_lut, qi_in, qi_out);
+            }
+            else
+            {
+                qasymm8_signed_logistic_populate_table(_lut, qi_in, qi_out);
+            }
+        }
     }
 #endif // __aarch64__
 
     static inline bool is_lut_supported(ActivationFunction act_func, DataType data_type)
     {
 #ifdef __aarch64__
-        auto supported = (data_type == DataType::QASYMM8 && (act_func == ActivationFunction::HARD_SWISH || act_func == ActivationFunction::LEAKY_RELU));
-        return supported;
+        switch(act_func)
+        {
+            case ActivationFunction::HARD_SWISH:
+            case ActivationFunction::LEAKY_RELU:
+                return data_type == DataType::QASYMM8;
+
+            case ActivationFunction::LOGISTIC:
+                return (data_type == DataType::QASYMM8) || (data_type == DataType::QASYMM8_SIGNED);
+
+            default:
+                return false;
+        }
 #else  // __aarch64__
         ARM_COMPUTE_UNUSED(act_func);
         ARM_COMPUTE_UNUSED(data_type);
@@ -1735,6 +1756,22 @@
             lut[i] = qasymm8_leaky_relu(i, qi_in, qi_out, alpha);
         }
     }
+
+    static inline void qasymm8_logistic_populate_table(LookupTable256 &lut, const UniformQuantizationInfo &qi_in, const UniformQuantizationInfo &qi_out)
+    {
+        for(size_t i = 0; i < lut.size(); ++i)
+        {
+            lut[i] = qasymm8_logistic(i, qi_in, qi_out);
+        }
+    }
+
+    static inline void qasymm8_signed_logistic_populate_table(LookupTable256 &lut, const UniformQuantizationInfo &qi_in, const UniformQuantizationInfo &qi_out)
+    {
+        for(size_t i = 0; i < lut.size(); ++i)
+        {
+            lut[i] = qasymm8_signed_logistic(static_cast<int8_t>(i), qi_in, qi_out);
+        }
+    }
 #endif // __aarch64__
 };