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ARROW-90: [C++] Check for SIMD instruction set support #50

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ARROW-90: [C++] Check for SIMD instruction set support #50

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26 changes: 25 additions & 1 deletion cpp/CMakeLists.txt
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Original file line number Diff line number Diff line change
Expand Up @@ -66,6 +66,14 @@ if("${CMAKE_SOURCE_DIR}" STREQUAL "${CMAKE_CURRENT_SOURCE_DIR}")
"Build the Arrow IPC extensions"
ON)

option(ARROW_SSE3
"Build Arrow with SSE3"
ON)

option(ARROW_ALTIVEC
"Build Arrow with Altivec"
ON)

endif()

if(NOT ARROW_BUILD_TESTS)
Expand All @@ -81,9 +89,25 @@ endif()
# Compiler flags
############################################################

# Check if the target architecture and compiler supports some special
# instruction sets that would boost performance.
include(CheckCXXCompilerFlag)
# x86/amd64 compiler flags
CHECK_CXX_COMPILER_FLAG("-msse3" CXX_SUPPORTS_SSE3)
# power compiler flags
CHECK_CXX_COMPILER_FLAG("-maltivec" CXX_SUPPORTS_ALTIVEC)

# compiler flags that are common across debug/release builds
# - Wall: Enable all warnings.
set(CXX_COMMON_FLAGS "-std=c++11 -msse3 -Wall")
set(CXX_COMMON_FLAGS "-std=c++11 -Wall")

# Only enable additional instruction sets if they are supported
if (CXX_SUPPORTS_SSE3 AND ARROW_SSE3)
set(CXX_COMMON_FLAGS "${CXX_COMMON_FLAGS} -msse3")
endif()
if (CXX_SUPPORTS_ALTIVEC AND ARROW_ALTIVEC)
set(CXX_COMMON_FLAGS "${CXX_COMMON_FLAGS} -maltivec")
endif()
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We're probably also going to want some defines so that we can include or exclude code that depends on these features, but doesn't need to be in this patch

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What implications does ARROW_SSE3=on by default have if we also add ARROW_SSE42 for SSE 4.2? I figure that -msse4.2 -msse3 is equivalent to just -msse3 but let me know if that is not the case

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-msse4.2 -msse3 can be used together and they will enable SSE3 and SSE4.2 support. The semantics of those switches are "also use this instruction set". It may even be that -msse4.2 implies -msse3 so that -msse4.2 -msse3 is actually equivalent to -msse4.2. In general those -m* options add up together to enable more instructions sets, not less.

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thank you, good to know


if (APPLE)
# Depending on the default OSX_DEPLOYMENT_TARGET (< 10.9), libstdc++ may be
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