added -ffast math compiler option

Author: leomccormack

CMakeLists.txt

@@ -15,6 +15,7 @@ option(SAF_USE_INTEL_IPP             "Use Intel IPP for the FFT, resampler, etc.
 option(SAF_USE_FFTW                  "Use FFTW3 for the FFT."                     OFF)
 option(SAF_ENABLE_SIMD               "Enable the use of SSE3, AVX2, AVX512"       OFF)
 option(SAF_ENABLE_NETCDF             "Enable netcdf for the sofa reader module"   OFF)
+option(SAF_USE_FAST_MATH_FLAG        "Enable -ffast-math compiler flag"           ON)
 if (NOT SAF_PERFORMANCE_LIB)
     set(SAF_PERFORMANCE_LIB "SAF_USE_INTEL_MKL_LP64" CACHE STRING "Performance library for SAF to use.")
 endif()

README.md

@@ -98,6 +98,7 @@ The available SAF-related CMake options (and their default values) are:
 -DSAF_BUILD_TESTS=1                          # build unit testing program
 -DSAF_USE_INTEL_IPP=0                        # link and use Intel IPP for the FFT, resampler, etc.
 -DSAF_ENABLE_SIMD=0                          # enable/disable SSE, AVX, and/or AVX-512 support
+-DSAF_USE_FAST_MATH_FLAG=1                   # enable the -ffast-math compiler flag on clang/gcc
 ```
 
 If using e.g. **SAF_USE_INTEL_MKL_LP64** as the performance library, note that the default header and library search paths may be overridden [according to your setup](docs/PERFORMANCE_LIBRARY_INSTRUCTIONS.md) with:

framework/CMakeLists.txt

@@ -357,9 +357,15 @@ endif()
 
 
 ############################################################################
+# Extra compiler flags
 if(UNIX)
     target_compile_options(${PROJECT_NAME} PRIVATE -Wall -Wextra)
 endif()
+if(SAF_USE_FAST_MATH_FLAG)
+    if((CMAKE_CXX_COMPILER_ID MATCHES "Clang") OR (CMAKE_CXX_COMPILER_ID MATCHES "GNU"))
+        add_compile_options(-ffast-math)
+    endif()
+endif()
 
 
 ############################################################################