From cd2011b61e77e10a148354879961263f8f077196 Mon Sep 17 00:00:00 2001
From: James Turner <zakalawe@mac.com>
Date: Tue, 26 May 2020 13:06:22 +0100
Subject: [PATCH] Change how SIMD compile flags are set

---
 CMakeLists.txt | 42 +++++++++++++++++-------------------------
 1 file changed, 17 insertions(+), 25 deletions(-)

diff --git a/CMakeLists.txt b/CMakeLists.txt
index 2269f6ae3..07747257b 100644
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -452,11 +452,8 @@ if(CMAKE_COMPILER_IS_GNUCXX)
        set(CMAKE_CXX_FLAGS "${CMAKE_CXX_FLAGS} -std=c++11")
     endif()
 
-    if (ENABLE_SIMD)
-      if (X86 OR X86_64)
-        set(CMAKE_C_FLAGS_RELEASE "-O3 -msse2 -mfpmath=sse -ftree-vectorize -ftree-slp-vectorize")
-        set(CMAKE_CXX_FLAGS_RELEASE "-O3 -msse2 -mfpmath=sse -ftree-vectorize -ftree-slp-vectorize")
-      endif()
+    if (X86 OR X86_64)
+        set(SIMD_COMPILER_FLAGS "-msse2 -mfpmath=sse -ftree-vectorize -ftree-slp-vectorize")
     endif()
 endif(CMAKE_COMPILER_IS_GNUCXX)
 
@@ -485,16 +482,7 @@ if (CMAKE_CXX_COMPILER_ID STREQUAL "Clang" OR CMAKE_CXX_COMPILER_ID STREQUAL "Ap
     set(CMAKE_CXX_FLAGS_RELWITHDEBINFO "-O3 -g -DNDEBUG")
     set(CMAKE_C_FLAGS_RELWITHDEBINFO  "-O3 -g -DNDEBUG")
 
-    if (ENABLE_SIMD)
-      if (X86 OR X86_64)
-        set(CMAKE_C_FLAGS_RELEASE "-O3 -msse2 -mfpmath=sse -ftree-vectorize -ftree-slp-vectorize")
-        set(CMAKE_CXX_FLAGS_RELEASE "-O3 -msse2 -mfpmath=sse -ftree-vectorize -ftree-slp-vectorize")
-
-        # propogate to the RelWithDebInfo flags
-        set(CMAKE_CXX_FLAGS_RELWITHDEBINFO "${CMAKE_CXX_FLAGS_RELEASE} -g -DNDEBUG")
-        set(CMAKE_C_FLAGS_RELWITHDEBINFO "${CMAKE_C_FLAGS_RELEASE} -g -DNDEBUG")
-      endif()
-    endif()
+    set(SIMD_COMPILER_FLAGS "-msse2 -mfpmath=sse -ftree-vectorize -ftree-slp-vectorize")
 
   set(CMAKE_XCODE_ATTRIBUTE_CLANG_CXX_LIBRARY "libc++")
    set(CMAKE_CXX_FLAGS "${CMAKE_CXX_FLAGS} -stdlib=libc++")
@@ -502,7 +490,6 @@ if (CMAKE_CXX_COMPILER_ID STREQUAL "Clang" OR CMAKE_CXX_COMPILER_ID STREQUAL "Ap
 endif()
 
 if(WIN32)
-
     if(MSVC)
         # override CMake default RelWithDebInfo flags. This is important to ensure
         # good performance
@@ -510,15 +497,7 @@ if(WIN32)
         set(CMAKE_C_FLAGS_RELWITHDEBINFO "/Zi /O2 /Ob2 /D NDEBUG")
 
         set(MSVC_FLAGS "-DNOMINMAX -D_USE_MATH_DEFINES -D_CRT_SECURE_NO_WARNINGS -D_SCL_SECURE_NO_WARNINGS -D__CRT_NONSTDC_NO_WARNINGS")
-        if(ENABLE_SIMD)
-          if (X86)
-            SET(CMAKE_C_FLAGS_RELEASE "/O2 /arch:SSE /arch:SSE2")
-            SET(CMAKE_CXX_FLAGS_RELEASE "/O2 /arch:SSE /arch:SSE2")
-          else()
-            SET(CMAKE_C_FLAGS_RELEASE "/O2")
-            SET(CMAKE_CXX_FLAGS_RELEASE "/O2")
-          endif()
-        endif()
+        set(SIMD_COMPILER_FLAGS "/arch:SSE /arch:SSE2")
 
         if (NOT OSG_FSTREAM_EXPORT_FIXED AND ${MSVC_VERSION} GREATER 1599)
           message(STATUS "For better linking performance, use OSG with fixed fstream header")
@@ -538,6 +517,19 @@ endif(WIN32)
 
 set (BOOST_CXX_FLAGS "-DBOOST_BIMAP_DISABLE_SERIALIZATION")
 
+# append the SIMD flags if requested
+if (ENABLE_SIMD)
+  set(CMAKE_C_FLAGS "${CMAKE_C_FLAGS} ${SIMD_COMPILER_FLAGS}")
+  set(CMAKE_CXX_FLAGS "${CMAKE_CXX_FLAGS} ${SIMD_COMPILER_FLAGS}")
+
+  # set for multi-configuration generators
+  set(CMAKE_C_FLAGS_RELEASE "${CMAKE_C_FLAGS_RELEASE} ${SIMD_COMPILER_FLAGS}")
+  set(CMAKE_CXX_FLAGS_RELEASE "${CMAKE_CXX_FLAGS_RELEASE} ${SIMD_COMPILER_FLAGS}")
+
+  set(CMAKE_C_FLAGS_RELWITHDEBINFO "${CMAKE_C_FLAGS_RELWITHDEBINFO} ${SIMD_COMPILER_FLAGS}")
+  set(CMAKE_CXX_FLAGS_RELWITHDEBINFO "${CMAKE_CXX_FLAGS_RELWITHDEBINFO} ${SIMD_COMPILER_FLAGS}")
+endif()
+
 set(CMAKE_C_FLAGS "${CMAKE_C_FLAGS} ${WARNING_FLAGS_C} ${MSVC_FLAGS} -D_REENTRANT")
 set(CMAKE_CXX_FLAGS "${CMAKE_CXX_FLAGS} ${WARNING_FLAGS_CXX} ${MSVC_FLAGS} -D_REENTRANT ${BOOST_CXX_FLAGS}")
 set(CMAKE_EXE_LINKER_FLAGS "${CMAKE_EXE_LINKER_FLAGS} ${MSVC_LD_FLAGS}")