Merge pull request #227 from james-d-mitchell/detect-march-native

Check for compiler support for '-march=native' flag

Author: JohanMabille

benchmark/CMakeLists.txt

@@ -23,7 +23,11 @@ include(CheckCXXCompilerFlag)
 string(TOUPPER "${CMAKE_BUILD_TYPE}" U_CMAKE_BUILD_TYPE)
 
 if (CMAKE_CXX_COMPILER_ID MATCHES "Clang" OR CMAKE_CXX_COMPILER_ID MATCHES "GNU" OR CMAKE_CXX_COMPILER_ID MATCHES "Intel")
-    set(CMAKE_CXX_FLAGS "${CMAKE_CXX_FLAGS} -march=native -Wunused-parameter -Wextra -Wreorder")
+    CHECK_CXX_COMPILER_FLAG(-march=native arch_native_supported)
+    if(arch_native_supported AND NOT CMAKE_CXX_FLAGS MATCHES "-march")
+        set(CMAKE_CXX_FLAGS "${CMAKE_CXX_FLAGS} -march=native")
+    endif()
+    set(CMAKE_CXX_FLAGS "${CMAKE_CXX_FLAGS} -Wunused-parameter -Wextra -Wreorder")
     CHECK_CXX_COMPILER_FLAG("-std=c++14" HAS_CPP14_FLAG)
 
     if (HAS_CPP14_FLAG)

test/CMakeLists.txt

@@ -57,7 +57,11 @@ if(NOT _cxx_std_flag)
 endif()
 
 if(CMAKE_CXX_COMPILER_ID MATCHES "GNU" OR (CMAKE_CXX_COMPILER_ID MATCHES "Intel" AND NOT WIN32))
-  set(CMAKE_CXX_FLAGS "${CMAKE_CXX_FLAGS} ${_cxx_std_flag} -march=native -Wunused-parameter -Wextra -Wreorder -Wconversion -Wsign-conversion")
+  CHECK_CXX_COMPILER_FLAG(-march=native arch_native_supported)
+  if(arch_native_supported AND NOT CMAKE_CXX_FLAGS MATCHES "-march")
+    set(CMAKE_CXX_FLAGS "${CMAKE_CXX_FLAGS} -march=native")
+  endif()
+  set(CMAKE_CXX_FLAGS "${CMAKE_CXX_FLAGS} ${_cxx_std_flag} -Wunused-parameter -Wextra -Wreorder -Wconversion -Wsign-conversion")
   set(CMAKE_CXX_FLAGS "${CMAKE_CXX_FLAGS} -Wold-style-cast -Wunused-variable")
 elseif(CMAKE_CXX_COMPILER_ID MATCHES "MSVC")
   set(CMAKE_CXX_FLAGS "${CMAKE_CXX_FLAGS} ${_cxx_std_flag} /EHsc /MP /bigobj /wd4800")
@@ -66,7 +70,11 @@ elseif(CMAKE_CXX_COMPILER_ID MATCHES "MSVC")
   add_definitions(-D_SILENCE_TR1_NAMESPACE_DEPRECATION_WARNING)
 elseif(CMAKE_CXX_COMPILER_ID MATCHES "Clang")
   if(NOT WIN32)
-    set(CMAKE_CXX_FLAGS "${CMAKE_CXX_FLAGS} ${_cxx_std_flag} -march=native -Wunused-parameter -Wextra -Wreorder -Wconversion -Wsign-conversion")
+    CHECK_CXX_COMPILER_FLAG(-march=native arch_native_supported)
+    if(arch_native_supported AND NOT CMAKE_CXX_FLAGS MATCHES "-march")
+      set(CMAKE_CXX_FLAGS "${CMAKE_CXX_FLAGS} -march=native")
+    endif()
+    set(CMAKE_CXX_FLAGS "${CMAKE_CXX_FLAGS} ${_cxx_std_flag} -Wunused-parameter -Wextra -Wreorder -Wconversion -Wsign-conversion")
     set(CMAKE_CXX_FLAGS "${CMAKE_CXX_FLAGS} -Wold-style-cast -Wunused-variable")
   else() # We are using clang-cl
     set(CMAKE_CXX_FLAGS "${CMAKE_CXX_FLAGS} ${_cxx_std_flag} /EHsc /MP /bigobj -Wno-unused-command-line-argument")