From 7b9ed50daaab32e39e5044633c379fc9947c32a7 Mon Sep 17 00:00:00 2001
From: chrisbeall <chrisbeall@gmail.com>
Date: Sat, 18 May 2019 15:15:27 -0700
Subject: [PATCH] Add option to toggle march=native

---
 CMakeLists.txt              | 1 +
 cmake/GtsamBuildTypes.cmake | 6 ++++++
 2 files changed, 7 insertions(+)

diff --git a/CMakeLists.txt b/CMakeLists.txt
index 29b31f979..ffcb5341f 100644
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -512,6 +512,7 @@ if(GTSAM_UNSTABLE_AVAILABLE)
     print_config_flag(${GTSAM_BUILD_UNSTABLE}          "Build libgtsam_unstable        ")
 endif()
 string(TOUPPER "${CMAKE_BUILD_TYPE}" cmake_build_type_toupper)
+print_config_flag(${GTSAM_BUILD_WITH_MARCH_NATIVE}     "Build for native architecture  ")
 if(NOT MSVC AND NOT XCODE_VERSION)
     message(STATUS "  Build type                     : ${CMAKE_BUILD_TYPE}")
     message(STATUS "  C compilation flags            : ${CMAKE_C_FLAGS} ${CMAKE_C_FLAGS_${cmake_build_type_toupper}}")
diff --git a/cmake/GtsamBuildTypes.cmake b/cmake/GtsamBuildTypes.cmake
index e9521c257..b80765298 100644
--- a/cmake/GtsamBuildTypes.cmake
+++ b/cmake/GtsamBuildTypes.cmake
@@ -90,6 +90,12 @@ if(${CMAKE_CXX_COMPILER_ID} STREQUAL "Clang")
     endif()
 endif()
 
+option(GTSAM_BUILD_WITH_MARCH_NATIVE  "Enable/Disable building with all instructions supported by native architecture (binary may not be portable!)" ON)
+if(GTSAM_BUILD_WITH_MARCH_NATIVE)
+  set(CMAKE_C_FLAGS "${CMAKE_C_FLAGS} -march=native")
+  set(CMAKE_CXX_FLAGS "${CMAKE_CXX_FLAGS} -march=native")
+endif()
+
 # Set up build type library postfixes
 if(GTSAM_BUILD_TYPE_POSTFIXES)
   foreach(build_type Debug Timing Profiling RelWithDebInfo MinSizeRel)