Default enable SSE only if compiler supports it (#514)

* Default enable SSE only if compiler supports it This fixes an issue seen in ROS Noetic where SSE is default enabled on an aarch64 system. CMake seems to think the host supports SSE, but the compiler does not. Signed-off-by: Shane Loretz <[email protected]> Signed-off-by: Shane Loretz <[email protected]>
flexible-collision-library · Dec 11, 2020 · da07e5b · da07e5b
1 parent 968fd7e
commit da07e5b
Showing 1 changed file with 20 additions and 10 deletions.
diff --git a/CMakeLists.txt b/CMakeLists.txt
@@ -79,30 +79,40 @@ else()
   option(FCL_STATIC_LIBRARY "Whether the FCL library should be static rather than shared" OFF)
 endif()
 
+set(SSE_FLAGS "")
+if(CMAKE_COMPILER_IS_GNUCXX OR CMAKE_CXX_COMPILER_ID MATCHES "Clang")
+  set(SSE_FLAGS -mfpmath=sse -msse -msse2 -msse3 -mssse3)
+elseif(MSVC)
+  # Win64 will add the flag automatically
+  if(CMAKE_VS_PLATFORM_NAME STREQUAL "Win32")
+    set(SSE_FLAGS /arch:SSE2)
+  endif()
+endif()
+
 # Whether to enable SSE
 if(CMAKE_SYSTEM_NAME STREQUAL "Emscripten")
   set(FCL_TARGET_SUPPORT_X64_SSE OFF)
 else()
+  # Does the host support SSE
   cmake_host_system_information(RESULT _has_sse QUERY HAS_SSE)
   cmake_host_system_information(RESULT _has_sse2 QUERY HAS_SSE2)
-  if(_has_sse AND _has_sse2)
+
+  # Does the compiler support SSE
+  include(CheckCXXCompilerFlag)
+  check_cxx_compiler_flag("${SSE_FLAGS}" _compiler_supports_sse)
+
+  if(_has_sse AND _has_sse2 AND _compiler_supports_sse)
     set(FCL_TARGET_SUPPORT_X64_SSE ON)
   else()
     set(FCL_TARGET_SUPPORT_X64_SSE OFF)
   endif()
 endif()
-set(SSE_FLAGS "")
 option(FCL_USE_X64_SSE "Whether FCL should x64 SSE instructions" ${FCL_TARGET_SUPPORT_X64_SSE})
 if(FCL_USE_X64_SSE)
-  if(CMAKE_COMPILER_IS_GNUCXX OR CMAKE_CXX_COMPILER_ID MATCHES "Clang")
-    set(SSE_FLAGS -mfpmath=sse -msse -msse2 -msse3 -mssse3)
-  elseif(MSVC)
-    # Win64 will add the flag automatically
-    if(CMAKE_VS_PLATFORM_NAME STREQUAL "Win32")
-      set(SSE_FLAGS /arch:SSE2)
-    endif()
-  endif()
   add_compile_options(${SSE_FLAGS})
+else()
+  # Unset SSE_FLAGS so it doesn't get used in subdirectories
+  set(SSE_FLAGS "")
 endif()
 
 option(FCL_USE_HOST_NATIVE_ARCH "Whether FCL should use cflags from the host used to compile" OFF)