Allow building without -march=native. Consider supporting builds for systems without SSE4.1.

[cho-m]

Currently, BEAGLE will always build with -march=native when the compiler supports it:

beagle-lib/CMakeLists.txt

Line 14 in 2af9116

set(BEAGLE_OPTIMIZE_FOR_NATIVE_ARCH true)

beagle-lib/CMakeLists.txt

Lines 119 to 123 in 2af9116

	if (BEAGLE_OPTIMIZE_FOR_NATIVE_ARCH)
	include(CheckCXXCompilerFlag)
	CHECK_CXX_COMPILER_FLAG("-march=native" COMPILER_OPT_ARCH_NATIVE_SUPPORTED)
	if (COMPILER_OPT_ARCH_NATIVE_SUPPORTED)
	set(CMAKE_CXX_FLAGS "${CMAKE_CXX_FLAGS} -march=native")

This makes it trickier to distribute binaries as users' systems may need to minimally match SIMD support of host.

In Homebrew, this may be the reason why we are occasionally hitting segfaults when testing packages that use BEAGLE (e.g. BEAST and MrBayes).

---

When experimenting with disabling BEAGLE_OPTIMIZE_FOR_NATIVE_ARCH, I saw the compilation would fail on _mm_dp_pd:

beagle-lib/libhmsbeagle/CPU/BeagleCPU4StateSSEImpl.hpp

Line 62 in 2af9116

VEC_ADD(_mm_dp_pd(lhs##01, rhs##01, 0xff), _mm_dp_pd(lhs##23, rhs##23, 0xff))

This appears to be a SSE4.1 intrinsic. So, when I removed -march=native, build was missing -msse4.1 needed to use the intrinsic.

In older BEAGLE releases, there was support for disabling SSE2:

beagle-lib/configure.ac

Line 315 in 35bbe78

AC_HELP_STRING([--disable-sse],[disable native sse implementation]), , [enable_sse=yes])

It would be nice to allow compiling without SSE4.1.

---

Specifically, in Homebrew, we want to build Linux binaries for Core2 (up to SSSE3) and macOS binaries for Nehalem (up to SSE4.2).

[cho-m]

Snippet of cmake --build output where -march=native is being passed to every compilation:

[  5%] Building CXX object libhmsbeagle/CMakeFiles/hmsbeagle.dir/beagle.cpp.o
cd /tmp/beagle-20221202-16102-yndsrr/beagle-lib-4.0.0/build/libhmsbeagle && /home/linuxbrew/.linuxbrew/Homebrew/Library/Homebrew/shims/linux/super/g++-11 -DPACKAGE_BUGREPORT=\"[email protected]\" -DPACKAGE_NAME=\"libhmsbeagle\" -DPACKAGE_STRING="\"libhmsbeagle 4.0.0\"" -DPACKAGE_TARNAME=\"libhmsbeagle\" -DPACKAGE_URL=\"\" -DPACKAGE_VERSION=\"4.0.0\" -DPLUGIN_VERSION=\"40\" -Dhmsbeagle_EXPORTS -I/tmp/beagle-20221202-16102-yndsrr/beagle-lib-4.0.0 -I/home/linuxbrew/.linuxbrew/opt/openjdk@11/libexec/include -std=c++11 -O3 -pthread -march=native -O2 -g -DNDEBUG -fPIC -std=gnu++11 -MD -MT libhmsbeagle/CMakeFiles/hmsbeagle.dir/beagle.cpp.o -MF CMakeFiles/hmsbeagle.dir/beagle.cpp.o.d -o CMakeFiles/hmsbeagle.dir/beagle.cpp.o -c /tmp/beagle-20221202-16102-yndsrr/beagle-lib-4.0.0/libhmsbeagle/beagle.cpp
[ 11%] Building CXX object libhmsbeagle/CPU/CMakeFiles/hmsbeagle-cpu.dir/BeagleCPUPlugin.cpp.o
cd /tmp/beagle-20221202-16102-yndsrr/beagle-lib-4.0.0/build/libhmsbeagle/CPU && /home/linuxbrew/.linuxbrew/Homebrew/Library/Homebrew/shims/linux/super/g++-11 -DPACKAGE_BUGREPORT=\"[email protected]\" -DPACKAGE_NAME=\"libhmsbeagle\" -DPACKAGE_STRING="\"libhmsbeagle 4.0.0\"" -DPACKAGE_TARNAME=\"libhmsbeagle\" -DPACKAGE_URL=\"\" -DPACKAGE_VERSION=\"4.0.0\" -DPLUGIN_VERSION=\"40\" -Dhmsbeagle_cpu_EXPORTS -I/tmp/beagle-20221202-16102-yndsrr/beagle-lib-4.0.0 -I/home/linuxbrew/.linuxbrew/opt/openjdk@11/libexec/include -std=c++11 -O3 -pthread -march=native -O2 -g -DNDEBUG -fPIC -std=gnu++11 -MD -MT libhmsbeagle/CPU/CMakeFiles/hmsbeagle-cpu.dir/BeagleCPUPlugin.cpp.o -MF CMakeFiles/hmsbeagle-cpu.dir/BeagleCPUPlugin.cpp.o.d -o CMakeFiles/hmsbeagle-cpu.dir/BeagleCPUPlugin.cpp.o -c /tmp/beagle-20221202-16102-yndsrr/beagle-lib-4.0.0/libhmsbeagle/CPU/BeagleCPUPlugin.cpp
[ 17%] Building CXX object libhmsbeagle/CMakeFiles/hmsbeagle.dir/benchmark/BeagleBenchmark.cpp.o
cd /tmp/beagle-20221202-16102-yndsrr/beagle-lib-4.0.0/build/libhmsbeagle && /home/linuxbrew/.linuxbrew/Homebrew/Library/Homebrew/shims/linux/super/g++-11 -DPACKAGE_BUGREPORT=\"[email protected]\" -DPACKAGE_NAME=\"libhmsbeagle\" -DPACKAGE_STRING="\"libhmsbeagle 4.0.0\"" -DPACKAGE_TARNAME=\"libhmsbeagle\" -DPACKAGE_URL=\"\" -DPACKAGE_VERSION=\"4.0.0\" -DPLUGIN_VERSION=\"40\" -Dhmsbeagle_EXPORTS -I/tmp/beagle-20221202-16102-yndsrr/beagle-lib-4.0.0 -I/home/linuxbrew/.linuxbrew/opt/openjdk@11/libexec/include -std=c++11 -O3 -pthread -march=native -O2 -g -DNDEBUG -fPIC -std=gnu++11 -MD -MT libhmsbeagle/CMakeFiles/hmsbeagle.dir/benchmark/BeagleBenchmark.cpp.o -MF CMakeFiles/hmsbeagle.dir/benchmark/BeagleBenchmark.cpp.o.d -o CMakeFiles/hmsbeagle.dir/benchmark/BeagleBenchmark.cpp.o -c /tmp/beagle-20221202-16102-yndsrr/beagle-lib-4.0.0/libhmsbeagle/benchmark/BeagleBenchmark.cpp

---

Error when building without -march=native:

  In file included from /tmp/beagle-20221210-16102-8nngbe/beagle-lib-4.0.0/libhmsbeagle/CPU/SSEDefinitions.h:66,
                   from /tmp/beagle-20221210-16102-8nngbe/beagle-lib-4.0.0/libhmsbeagle/CPU/BeagleCPU4StateSSEImpl.hpp:34,
                   from /tmp/beagle-20221210-16102-8nngbe/beagle-lib-4.0.0/libhmsbeagle/CPU/BeagleCPU4StateSSEImpl.h:338,
                   from /tmp/beagle-20221210-16102-8nngbe/beagle-lib-4.0.0/libhmsbeagle/CPU/BeagleCPUSSEPlugin.cpp:9:
  /usr/lib/gcc/x86_64-linux-gnu/11/include/smmintrin.h: In member function ‘void beagle::cpu::BeagleCPU4StateSSEImpl<double, T_PAD, P_PAD>::calcCrossProductsPartials(const double*, const double*, const double*, const double*, double, double*, double*) [with int T_PAD = 2; int P_PAD = 0]’:
  /usr/lib/gcc/x86_64-linux-gnu/11/include/smmintrin.h:249:1: error: inlining failed in call to ‘always_inline’ ‘__m128d _mm_dp_pd(__m128d, __m128d, int)’: target specific option mismatch
    249 | _mm_dp_pd (__m128d __X, __m128d __Y, const int __M)
        | ^~~~~~~~~

---

Looking at workarounds for Homebrew in Homebrew/homebrew-core#117835

[msuchard]

commit 2883ced adds an option to disable SSE build (-DBUILD_SSE=OFF), although this seems like a really bad idea. SSE4.1 was released >10 years ago.