add widening horizontal add for s16 vectors

CMakeLists.txt

@@ -17,6 +17,7 @@ add_subdirectory(external/highway)
 # Collect source files
 file(GLOB SOURCE_FILES
         "quicktex/*.cpp"
+        "quicktex/tests/*.cpp"
         "quicktex/s3tc/*.cpp"
         "quicktex/s3tc/bc1/*.cpp"
         "quicktex/s3tc/bc3/*.cpp"
@@ -27,6 +28,7 @@ file(GLOB SOURCE_FILES
 
 file(GLOB HEADER_FILES
         "quicktex/*.h"
+        "quicktex/tests/*.h"
         "quicktex/s3tc/*.h"
         "quicktex/s3tc/bc1/*.h"
         "quicktex/s3tc/bc3/*.h"
@@ -53,6 +55,8 @@ if (OpenMP_CXX_FOUND)
     target_link_libraries(_quicktex PUBLIC OpenMP::OpenMP_CXX)
 endif ()
 
+target_link_libraries(_quicktex PUBLIC hwy)
+
 # Set module features, like C/C++ standards
 target_compile_features(_quicktex PUBLIC cxx_std_17 c_std_11)
 

quicktex/VecUtil.h

@@ -0,0 +1,84 @@
+/*  Quicktex Texture Compression Library
+    Copyright (C) 2021 Andrew Cassidy <drewcassidy@me.com>
+    Partially derived from rgbcx.h written by Richard Geldreich <richgel99@gmail.com>
+    and licenced under the public domain
+
+    This program is free software: you can redistribute it and/or modify
+    it under the terms of the GNU Lesser General Public License as published by
+    the Free Software Foundation, either version 3 of the License, or
+    (at your option) any later version.
+
+    This program is distributed in the hope that it will be useful,
+    but WITHOUT ANY WARRANTY; without even the implied warranty of
+    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+    GNU Lesser General Public License for more details.
+
+    You should have received a copy of the GNU Lesser General Public License
+    along with this program.  If not, see <http://www.gnu.org/licenses/>.
+ */
+
+#pragma once
+
+#include <hwy/highway.h>
+
+namespace hn = hwy::HWY_NAMESPACE;
+
+#if HWY_TARGET == HWY_NEON
+#include <arm_neon.h>
+#elif HWY_ARCH_X86_64
+#include <immintrin.h>
+#endif
+
+namespace quicktex {
+
+using Tag_s16 = hn::ScalableTag<int16_t>;
+using Vec_s16 = hn::Vec<Tag_s16>;
+using Tag_s32 = hn::ScalableTag<int32_t>;
+using Vec_s32 = hn::Vec<Tag_s32>;
+
+const Tag_s16 TagS16;
+const Tag_s32 TagS32;
+
+/// Helper function for doing sum-of-lanes without a tag lvalue. We're not targeting SVE (yet) so this should work fine.
+/// \tparam V Vector type to sum (8- and 16-bit integers are NOT supported)
+/// \param v Vector to sum
+/// \return The sum of all lanes in each lane.
+template <typename V> inline V SumOfLanes(V v) {
+    hn::DFromV<V> tag;
+    return hn::SumOfLanes(tag, v);
+}
+
+inline int32_t WideningSumS16(const Vec_s16 v) {
+#if HWY_TARGET == HWY_SCALAR
+    // In Scalar mode this is a no-op, since there's only one lane
+    return (int32_t)v.raw;
+#elif HWY_TARGET == HWY_NEON
+    static_assert(hn::MaxLanes(TagS16) == 8);
+    static_assert(hn::MaxLanes(TagS32) == 4);
+
+    // Pairwise widening sum, then sum all N/2 widened lanes
+    auto paired = Vec_s32(vpaddlq_s16(v.raw));
+    auto sums = SumOfLanes(paired);
+    return hn::GetLane(sums);
+#elif HWY_ARCH_X86_64
+#if HWY_TARGET == HWY_AVX2 || HWY_TARGET == HWY_AVX3
+    static_assert(hn::MaxLanes(TagS16) == 16);
+    static_assert(hn::MaxLanes(TagS32) == 8);
+
+    // Pairwise widening sum with multiply by 1, then sum all N/2 widened lanes
+    auto paired = Vec_s32(_mm256_madd_epi16(v.raw, __mm256_set1_epi16(1)));
+    auto sums = SumOfLanes(paired);
+    return hn::GetLane(sums);
+#else
+    static_assert(hn::MaxLanes(TagS16) == 8);
+    static_assert(hn::MaxLanes(TagS32) == 4);
+
+    // Pairwise widening sum with multiply by 1, then sum all N/2 widened lanes
+    auto paired = Vec_s32(_mm_madd_epi16(v.raw, _mm_set1_epi16(1)));
+    auto sums = SumOfLanes(paired);
+    return hn::GetLane(sums);
+#endif
+#endif
+}
+
+}  // namespace quicktex

quicktex/_bindings.cpp

@@ -35,6 +35,7 @@ namespace py = pybind11;
 namespace quicktex::bindings {
 
 void InitS3TC(py::module_ &m);
+void InitCTests(py::module_ &m);
 
 PYBIND11_MODULE(_quicktex, m) {
     m.doc() = "More Stuff";
@@ -69,6 +70,7 @@ PYBIND11_MODULE(_quicktex, m) {
     DefSubscript2D(raw_texture, &RawTexture::GetPixel, &RawTexture::SetPixel, &RawTexture::Size);
 
     InitS3TC(m);
+    InitCTests(m);
 }
 
 }  // namespace quicktex::bindings

quicktex/s3tc/bc1/BC1Encoder.cpp

@@ -37,6 +37,7 @@
 #include "../../Vector4Int.h"
 #include "../../bitwiseEnums.h"
 #include "../../util.h"
+#include "../../VecUtil.h"
 #include "Histogram.h"
 #include "OrderTable.h"
 #include "SingleColorTable.h"

quicktex/tests/TestSIMD.cpp

@@ -0,0 +1,65 @@
+/*  Quicktex Texture Compression Library
+    Copyright (C) 2021 Andrew Cassidy <drewcassidy@me.com>
+    Partially derived from rgbcx.h written by Richard Geldreich <richgel99@gmail.com>
+    and licenced under the public domain
+
+    This program is free software: you can redistribute it and/or modify
+    it under the terms of the GNU Lesser General Public License as published by
+    the Free Software Foundation, either version 3 of the License, or
+    (at your option) any later version.
+
+    This program is distributed in the hope that it will be useful,
+    but WITHOUT ANY WARRANTY; without even the implied warranty of
+    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+    GNU Lesser General Public License for more details.
+
+    You should have received a copy of the GNU Lesser General Public License
+    along with this program.  If not, see <http://www.gnu.org/licenses/>.
+ */
+
+#include "TestSIMD.h"
+
+#include <hwy/highway.h>
+
+#include <array>
+#include <cassert>
+#include <cstdint>
+#include <numeric>
+
+#include "../VecUtil.h"
+
+namespace hn = hwy::HWY_NAMESPACE;
+
+namespace quicktex::tests {
+
+void TestWidenSumS16() {
+    const hn::ScalableTag<int16_t> tag;
+    const auto vec_size = hn::MaxLanes(tag);
+    std::array<int16_t, vec_size> buffer;
+
+    std::iota(buffer.begin(), buffer.end(), 1);
+    auto v = hn::Load(tag, &buffer[0]);
+    auto sum = WideningSumS16(v);
+    assert(sum == vec_size / 2 * (vec_size + 1));  // Gauss formula
+
+    buffer.fill(1);
+    v = hn::Load(tag, &buffer[0]);
+    sum = WideningSumS16(v);
+    assert(sum == vec_size);
+
+    buffer.fill(0);
+    v = hn::Load(tag, &buffer[0]);
+    sum= WideningSumS16(v);
+    assert(sum == 0);
+
+    buffer.fill(std::numeric_limits<int16_t>::max());
+    v = hn::Load(tag, &buffer[0]);
+    sum= WideningSumS16(v);
+    assert(sum == std::numeric_limits<int16_t>::max() * (int)vec_size);
+
+    buffer.fill(std::numeric_limits<int16_t>::min());
+    v = hn::Load(tag, &buffer[0]);
+    sum= WideningSumS16(v);
+    assert(sum == std::numeric_limits<int16_t>::min() * (int)vec_size);
+}
+}  // namespace quicktex::tests

quicktex/tests/TestSIMD.h

@@ -0,0 +1,26 @@
+/*  Quicktex Texture Compression Library
+    Copyright (C) 2021 Andrew Cassidy <drewcassidy@me.com>
+    Partially derived from rgbcx.h written by Richard Geldreich <richgel99@gmail.com>
+    and licenced under the public domain
+
+    This program is free software: you can redistribute it and/or modify
+    it under the terms of the GNU Lesser General Public License as published by
+    the Free Software Foundation, either version 3 of the License, or
+    (at your option) any later version.
+
+    This program is distributed in the hope that it will be useful,
+    but WITHOUT ANY WARRANTY; without even the implied warranty of
+    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+    GNU Lesser General Public License for more details.
+
+    You should have received a copy of the GNU Lesser General Public License
+    along with this program.  If not, see <http://www.gnu.org/licenses/>.
+ */
+
+#pragma once
+
+namespace quicktex::tests {
+
+void TestWidenSumS16();
+
+} // namespace quicktex::tests

quicktex/tests/_bindings.cpp

@@ -0,0 +1,44 @@
+/*  Quicktex Texture Compression Library
+    Copyright (C) 2021 Andrew Cassidy <drewcassidy@me.com>
+    Partially derived from rgbcx.h written by Richard Geldreich <richgel99@gmail.com>
+    and licenced under the public domain
+
+    This program is free software: you can redistribute it and/or modify
+    it under the terms of the GNU Lesser General Public License as published by
+    the Free Software Foundation, either version 3 of the License, or
+    (at your option) any later version.
+
+    This program is distributed in the hope that it will be useful,
+    but WITHOUT ANY WARRANTY; without even the implied warranty of
+    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+    GNU Lesser General Public License for more details.
+
+    You should have received a copy of the GNU Lesser General Public License
+    along with this program.  If not, see <http://www.gnu.org/licenses/>.
+ */
+
+#include "../_bindings.h"
+
+#include <pybind11/pybind11.h>
+#include <pybind11/stl.h>
+
+#include <array>
+#include <cstddef>
+#include <cstdint>
+#include <stdexcept>
+#include <string>
+
+#include "TestSIMD.h"
+
+namespace py = pybind11;
+namespace quicktex::bindings {
+
+using namespace pybind11::literals;
+using namespace quicktex::tests;
+
+void InitCTests(py::module_ &quicktex) {
+    py::module_ ctests = quicktex.def_submodule("_ctests", "Internal tests for C-level functions");
+
+    ctests.def("test_WidenSumS16", &TestWidenSumS16);
+}
+}  // namespace quicktex::bindings

tests/test_ctest.py

@@ -0,0 +1,8 @@
+import unittest
+
+import _quicktex._ctests as c
+
+
+class TestCTest(unittest.TestCase):
+    def test_WidenSumS16(self):
+        c.test_WidenSumS16()

tools/CompilerWarnings.cmake

@@ -52,7 +52,7 @@ function(set_project_warnings project_name)
             -Wunused         # warn on anything being unused
             -Woverloaded-virtual # warn if you overload (not override) a virtual
             # function
-            -Wpedantic   # warn if non-standard C++ is used
+#            -Wpedantic   # warn if non-standard C++ is used
             #-Wconversion # warn on type conversions that may lose data
             #-Wsign-conversion  # warn on sign conversions
             -Wnull-dereference # warn if a null dereference is detected