1 files changed, 83 insertions, 0 deletions
diff --git a/include/tools/simdsupport.hxx b/include/tools/simdsupport.hxx
new file mode 100644
index 000000000..fa8923bb0
--- /dev/null
+++ b/include/tools/simdsupport.hxx
@@ -0,0 +1,83 @@
+/* -*- Mode: C++; tab-width: 4; indent-tabs-mode: nil; c-basic-offset: 4 -*- */
+/*
+ * This file is part of the LibreOffice project.
+ *
+ * This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/.
+ *
+ */
+
+// IMPORTANT: Having CPU-specific routines turned out to be a maintenance
+// problem, because of various problems such as compilers moving CPU-specific
+// code out of #ifdef code into static initialization or our code using C++
+// features that caused the compiler to emit code that used CPU-specific
+// instructions (even cpuid.hxx isn't safe, see the comment there).
+// The only safe usage is using CPU-specific code that's always available,
+// such as SSE2-specific code for x86_64. Do not use for anything else
+// unless you really know what you are doing (and you check git history
+// to learn from past problems).
+
+// Determine the compiler support for SIMD compiler intrinsics.
+// This changes from one compiled unit to the other, depending if
+// the support has been detected and if the compiled unit contains
+// code using intrinsics or not. So we have to (re)set them again
+// every time this file has been included.
+
+// In other words... DO NOT ADD "#pragma once" here
+
+#undef LO_SSE2_AVAILABLE
+#undef LO_SSSE3_AVAILABLE
+#undef LO_AVX_AVAILABLE
+#undef LO_AVX2_AVAILABLE
+#undef LO_AVX512F_AVAILABLE
+
+#if defined(_MSC_VER) // VISUAL STUDIO COMPILER
+
+// With MSVC using -arch is in fact not necessary for being able
+// to use CPU intrinsics, code using AVX512F intrinsics will compile
+// even if compiled with -arch:AVX, the -arch option really only affects
+// instructions generated for C/C++ code.
+#if defined(_M_X64) || defined(_M_X86)
+// As such, if we're building for X86 or X64, support for these is always available
+// with MSVC2019+.
+#define LO_SSE2_AVAILABLE
+#define LO_SSSE3_AVAILABLE
+#define LO_AVX_AVAILABLE
+#define LO_AVX2_AVAILABLE
+#define LO_AVX512F_AVAILABLE
+#include <intrin.h>
+#include <immintrin.h>
+#endif
+
+#else // compiler Clang and GCC
+
+#if defined(__SSE2__) || defined(__x86_64__) // SSE2 is required for X64
+#define LO_SSE2_AVAILABLE
+#include <emmintrin.h>
+#endif // defined(__SSE2__)
+
+#if defined(__SSSE3__)
+#define LO_SSSE3_AVAILABLE
+#include <tmmintrin.h>
+#endif // defined(__SSSE3__)
+
+#if defined(__AVX__)
+#define LO_AVX_AVAILABLE
+#include <immintrin.h>
+#endif // defined(__AVX__)
+
+#if defined(__AVX2__)
+#define LO_AVX2_AVAILABLE
+#include <immintrin.h>
+#endif // defined(__AVX2__)
+
+#if defined(__AVX512F__)
+#define LO_AVX512F_AVAILABLE
+#include <immintrin.h>
+#else
+#endif // defined(__AVX512F__)
+
+#endif // end compiler Clang and GCC
+
+/* vim:set shiftwidth=4 softtabstop=4 expandtab: */