office-gobmx/include/tools/cpuid.hxx
Luboš Luňák 2d36e7f518 remove AVX and AVX512 code from Calc
It's been a source of numerous problems since the beginning.
Poor separation of C++ code causing the compiler to emit some generic
code as CPU-specific, compiler optimizations moving CPU-specific
code out of #ifdef to unguarded static initialization, etc.

And it doesn't seem to even particularly improve performance,
on my Ryzen2500U for one full column (1m cells) sumArray() takes
about 1.6ms with AVX, 1.9ms with SSE2 and 4.6ms with generic code.
So SSE2 code is perhaps worth it, especially given that SSE2 is our
baseline requirement on x86_64 everywhere and x86 on Windows,
but AVX+ is nowhere near worth the trouble.

So this code removes all AVX+ code from Calc, and makes SSE2
a hardcoded option on where it's guaranteed. If we raise the baseline
to AVX, the SSE2 code may be replaced by the one removed by this
commit. Generic code is there for other platforms, if other platforms
add CPU-specific code, they should preferably follow the same rules.

This does not necessarily mean that CPU-specific code cannot
be used at all. Some externals use them, for example. It just
needs to be working, maintained, and worth the trouble.

Change-Id: I5ab919930df9d0223db68a94bf84947984d313ac
Reviewed-on: https://gerrit.libreoffice.org/c/core/+/129733
Tested-by: Jenkins
Reviewed-by: Eike Rathke <erack@redhat.com>
2022-02-10 16:33:07 +01:00

109 lines
2.5 KiB
C++

/* -*- 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/.
*
*/
#pragma once
#include <sal/config.h>
#include <tools/toolsdllapi.h>
#include <o3tl/typed_flags_set.hxx>
#include <rtl/ustring.hxx>
/*
Do NOT include this header in source files compiled with CPU-specific code.
TODO: For the header to be safe that way, it should be free of any templates
or inline functions, otherwise their possibly emitted copies compiled
with the CPU-specific instructions might be chosen by the linker as the copy
to keep.
Also see the note at the top of simdsupport.hxx .
*/
namespace cpuid {
enum class InstructionSetFlags
{
NONE = 0x00,
HYPER = 0x01,
SSE2 = 0x02,
SSSE3 = 0x04,
SSE41 = 0x08,
SSE42 = 0x10,
AVX = 0x20,
AVX2 = 0x40,
AVX512F = 0x80
};
} // end cpuid
namespace o3tl {
template<> struct typed_flags<cpuid::InstructionSetFlags> : is_typed_flags<cpuid::InstructionSetFlags, 0x0ff> {};
}
namespace cpuid {
/** Get supported instruction set flags determined at runtime by probing the CPU.
*/
TOOLS_DLLPUBLIC InstructionSetFlags getCpuInstructionSetFlags();
/** Check if a certain instruction set is supported by the CPU at runtime.
*/
TOOLS_DLLPUBLIC bool isCpuInstructionSetSupported(InstructionSetFlags eInstructions);
/** Returns a string of supported instructions.
*/
TOOLS_DLLPUBLIC OUString instructionSetSupportedString();
/** Check if SSE2 is supported by the CPU
*/
inline bool hasSSE2()
{
return isCpuInstructionSetSupported(InstructionSetFlags::SSE2);
}
/** Check if SSSE3 is supported by the CPU
*/
inline bool hasSSSE3()
{
return isCpuInstructionSetSupported(InstructionSetFlags::SSSE3);
}
/** Check if AVX is supported by the CPU
*/
inline bool hasAVX()
{
return isCpuInstructionSetSupported(InstructionSetFlags::AVX);
}
/** Check if AVX2 is supported by the CPU
*/
inline bool hasAVX2()
{
return isCpuInstructionSetSupported(InstructionSetFlags::AVX2);
}
/** Check if AVX512F is supported by the CPU
*/
inline bool hasAVX512F()
{
return isCpuInstructionSetSupported(InstructionSetFlags::AVX512F);
}
/** Check if Hyper Threading is supported
*/
inline bool hasHyperThreading()
{
return isCpuInstructionSetSupported(InstructionSetFlags::HYPER);
}
} // end cpuid
/* vim:set shiftwidth=4 softtabstop=4 expandtab: */