COMPMID-3853: Decouple NEActivationLayer

Decouple datatypes and remove Activation template.
Binary size dropped by 25Kb.

Signed-off-by: Michalis Spyrou <michalis.spyrou@arm.com>
Change-Id: I32c207db124895fee25b56437f9495403315b867
Reviewed-on: https://review.mlplatform.org/c/ml/ComputeLibrary/+/4217
Tested-by: Arm Jenkins <bsgcomp@arm.com>
Reviewed-by: Georgios Pinitas <georgios.pinitas@arm.com>
Comments-Addressed: Arm Jenkins <bsgcomp@arm.com>
diff --git a/src/core/NEON/kernels/activation/impl/fp32_neon_activation.cpp b/src/core/NEON/kernels/activation/impl/fp32_neon_activation.cpp
new file mode 100644
index 0000000..610db05
--- /dev/null
+++ b/src/core/NEON/kernels/activation/impl/fp32_neon_activation.cpp
@@ -0,0 +1,211 @@
+/*
+ * Copyright (c) 2020 Arm Limited.
+ *
+ * SPDX-License-Identifier: MIT
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a copy
+ * of this software and associated documentation files (the "Software"), to
+ * deal in the Software without restriction, including without limitation the
+ * rights to use, copy, modify, merge, publish, distribute, sublicense, and/or
+ * sell copies of the Software, and to permit persons to whom the Software is
+ * furnished to do so, subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice shall be included in all
+ * copies or substantial portions of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+ * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+ * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+ * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
+ * SOFTWARE.
+ */
+#include "arm_compute/core/Helpers.h"
+#include "arm_compute/core/ITensorPack.h"
+#include "arm_compute/core/Window.h"
+#include "src/core/NEON/NEMath.h"
+#include "src/core/NEON/wrapper/wrapper.h"
+#include "src/core/common/StdTypes.h"
+#include "src/core/common/Validate.h"
+
+#include <arm_neon.h>
+#include <cmath>
+#include <cstddef>
+
+namespace arm_compute
+{
+namespace cpu
+{
+namespace
+{
+#ifndef __aarch64__
+inline float32x4_t mask_float_vector(const float32x4_t &in, const uint32x4_t &mask)
+{
+    auto int_in = vreinterpretq_u32_f32(in);
+    return vreinterpretq_f32_u32(wrapper::vand(int_in, mask));
+}
+#endif /* __arch64__ */
+} // namespace
+
+void fp32_neon_activation(const ITensor *src, ITensor *dst, const ActivationLayerInfo &act_info, const Window &window)
+{
+    /** NEON vector tag type. */
+    using ExactTagType = typename arm_compute::wrapper::traits::neon_bitvector_tag_t<float, wrapper::traits::BitWidth::W128>;
+
+    constexpr int                                 window_step_x  = 4;
+    const auto                                    window_start_x = static_cast<int>(window.x().start());
+    const auto                                    window_end_x   = static_cast<int>(window.x().end());
+    const ActivationLayerInfo::ActivationFunction act            = act_info.activation();
+
+    Window win_collapsed = window.collapse_if_possible(window, Window::DimZ);
+    win_collapsed.set(Window::DimX, Window::Dimension(0, 1, 1));
+
+    Iterator input(src, win_collapsed);
+    Iterator output(dst, win_collapsed);
+
+    // In case of non-aarch64, a small delta value is added to the input
+    // to prevent NAN values caused by zeros in inputs to SQRT.
+    // In case of aarh64, we call vsqrt directly, so we don't use delta.
+#ifndef __aarch64__
+    const auto delta = wrapper::vdup_n(static_cast<float>(1e-24), ExactTagType {});
+#endif /* __aarch64 */
+    const auto const_1     = wrapper::vdup_n(static_cast<float>(1.f), ExactTagType {});
+    const auto const_0     = wrapper::vdup_n(static_cast<float>(0.f), ExactTagType{});
+    const auto const_6     = wrapper::vdup_n(static_cast<float>(6.f), ExactTagType{});
+    const auto const_3     = wrapper::vdup_n(static_cast<float>(3.f), ExactTagType{});
+    const auto const_inv_6 = wrapper::vdup_n(static_cast<float>(0.166666667f), ExactTagType{});
+
+    const auto va = wrapper::vdup_n(static_cast<float>(act_info.a()), ExactTagType{});
+    const auto vb = wrapper::vdup_n(static_cast<float>(act_info.b()), ExactTagType{});
+    const auto a  = static_cast<float>(act_info.a());
+    const auto b  = static_cast<float>(act_info.b());
+    execute_window_loop(win_collapsed, [&](const Coordinates &)
+    {
+        const auto input_ptr  = reinterpret_cast<const float *>(input.ptr());
+        const auto output_ptr = reinterpret_cast<float *>(output.ptr());
+
+        wrapper::traits::neon_bitvector_t<float, wrapper::traits::BitWidth::W128> tmp;
+
+        // Compute S elements per iteration
+        int x = window_start_x;
+        for(; x <= (window_end_x - window_step_x); x += window_step_x)
+        {
+            const auto vin = wrapper::vloadq(input_ptr + x);
+            switch(act)
+            {
+                case ActivationLayerInfo::ActivationFunction::ABS:
+                    tmp = wrapper::vabs(vin);
+                    break;
+                case ActivationLayerInfo::ActivationFunction::LINEAR:
+                    tmp = wrapper::vmla(vb, va, vin);
+                    break;
+                case ActivationLayerInfo::ActivationFunction::LOGISTIC:
+                    tmp = wrapper::vinv(wrapper::vadd(const_1, wrapper::vexpq(wrapper::vneg(vin))));
+                    break;
+                case ActivationLayerInfo::ActivationFunction::RELU:
+                    tmp = wrapper::vmax(const_0, vin);
+                    break;
+                case ActivationLayerInfo::ActivationFunction::BOUNDED_RELU:
+                    tmp = wrapper::vmin(va, wrapper::vmax(const_0, vin));
+                    break;
+                case ActivationLayerInfo::ActivationFunction::LU_BOUNDED_RELU:
+                    tmp = wrapper::vmin(va, wrapper::vmax(vb, vin));
+                    break;
+                case ActivationLayerInfo::ActivationFunction::LEAKY_RELU:
+                    tmp = wrapper::vbsl(wrapper::vcgt(vin, const_0), vin, wrapper::vmul(va, vin));
+                    break;
+                case ActivationLayerInfo::ActivationFunction::SOFT_RELU:
+                    tmp = wrapper::vlog(wrapper::vadd(const_1, wrapper::vexpq(vin)));
+                    break;
+                case ActivationLayerInfo::ActivationFunction::ELU:
+                    tmp = wrapper::vbsl(wrapper::vcge(vin, const_0), vin, wrapper::vmul(va, wrapper::vsub(wrapper::vexpq(vin), const_1)));
+                    break;
+                case ActivationLayerInfo::ActivationFunction::SQRT:
+#ifdef __aarch64__
+                    tmp = wrapper::vsqrt(vin);
+#else  /* aarch64 */
+                    {
+                        const auto bitmask = wrapper::vceq(vin, wrapper::vdup_n(0.f, ExactTagType{}));
+                        tmp                 = wrapper::vinv(wrapper::vinvsqrt(wrapper::vadd(vin, mask_float_vector(delta, bitmask))));
+                        tmp                 = mask_float_vector(tmp, wrapper::vnot(bitmask));
+                    }
+#endif /* aarch64 */
+                    break;
+                case ActivationLayerInfo::ActivationFunction::SQUARE:
+                    tmp = wrapper::vmul(vin, vin);
+                    break;
+                case ActivationLayerInfo::ActivationFunction::TANH:
+                    tmp = wrapper::vmul(va, wrapper::vtanh(wrapper::vmul(vb, vin)));
+                    break;
+                case ActivationLayerInfo::ActivationFunction::IDENTITY:
+                    tmp = vin;
+                    break;
+                case ActivationLayerInfo::ActivationFunction::HARD_SWISH:
+                    tmp = wrapper::vmul(vin, wrapper::vmul(const_inv_6, wrapper::vmin(const_6, wrapper::vmax(const_0, wrapper::vadd(vin, const_3)))));
+                    break;
+                default:
+                    ARM_COMPUTE_ERROR("Unsupported activation function");
+            }
+            wrapper::vstore(output_ptr + x, tmp);
+        }
+
+        // Compute left-over elements
+        for(; x < window_end_x; ++x)
+        {
+            const float in = *(reinterpret_cast<const float *>(input_ptr + x));
+            float       tmp;
+            switch(act)
+            {
+                case ActivationLayerInfo::ActivationFunction::ABS:
+                    tmp = std::abs(in);
+                    break;
+                case ActivationLayerInfo::ActivationFunction::LINEAR:
+                    tmp = a * in + b;
+                    break;
+                case ActivationLayerInfo::ActivationFunction::LOGISTIC:
+                    tmp = static_cast<float>(1) / (static_cast<float>(1) + std::exp(-in));
+                    break;
+                case ActivationLayerInfo::ActivationFunction::RELU:
+                    tmp = std::max<float>(static_cast<float>(0), in);
+                    break;
+                case ActivationLayerInfo::ActivationFunction::BOUNDED_RELU:
+                    tmp = std::min<float>(a, std::max(static_cast<float>(0), in));
+                    break;
+                case ActivationLayerInfo::ActivationFunction::LU_BOUNDED_RELU:
+                    tmp = std::min<float>(a, std::max<float>(b, in));
+                    break;
+                case ActivationLayerInfo::ActivationFunction::LEAKY_RELU:
+                    tmp = (in > 0) ? in : a * in;
+                    break;
+                case ActivationLayerInfo::ActivationFunction::SOFT_RELU:
+                    tmp = std::log(static_cast<float>(1) + std::exp(in));
+                    break;
+                case ActivationLayerInfo::ActivationFunction::ELU:
+                    tmp = (in >= 0) ? in : a * (std::exp(in) - 1);
+                    break;
+                case ActivationLayerInfo::ActivationFunction::SQRT:
+                    tmp = std::sqrt(in);
+                    break;
+                case ActivationLayerInfo::ActivationFunction::SQUARE:
+                    tmp = in * in;
+                    break;
+                case ActivationLayerInfo::ActivationFunction::TANH:
+                    tmp = a * std::tanh(b * in);
+                    break;
+                case ActivationLayerInfo::ActivationFunction::IDENTITY:
+                    tmp = in;
+                    break;
+                case ActivationLayerInfo::ActivationFunction::HARD_SWISH:
+                    tmp = in * ((std::min(std::max((in + 3), 0.0f), 6.0f)) * 0.166666667f);
+                    break;
+                default:
+                    ARM_COMPUTE_ERROR("Unsupported activation function");
+            }
+            *(output_ptr + x) = tmp;
+        }
+    },
+    input, output);
+}
+} // namespace cpu
+} // namespace arm_compute