Ditch -Ofast as it breaks spec tests

CMakeLists.txt

@@ -86,19 +86,13 @@ elseif(WIN32)
 
     #set(CMAKE_EXE_LINKER_FLAGS "${CMAKE_EXE_LINKER_FLAGS} /DEBUG:FULL")
   else()
-    set(CMAKE_C_FLAGS_RELEASE "${CMAKE_C_FLAGS_RELEASE} /Oxs /Oy /GS- /Qvec -Clang -Ofast")
+    set(CMAKE_C_FLAGS_RELEASE "${CMAKE_C_FLAGS_RELEASE} /Oxs /Oy /GS- /Qvec -Clang -O3")
   endif()
 else()
   set(CMAKE_C_FLAGS "${CMAKE_C_FLAGS} -Wall -Wextra -Wstrict-aliasing -Wno-unused-function -Wno-unused-variable -Wno-unused-parameter -Wno-missing-field-initializers")
   set(CMAKE_C_FLAGS_DEBUG "${CMAKE_C_FLAGS_DEBUG} -ggdb -O0")
 
-  if (CMAKE_C_COMPILER_ID MATCHES "GNU")
-    set(OPT_FLAGS "-O3")
-  else()
-    set(OPT_FLAGS "-Ofast")
-  endif()
-
-  set(CMAKE_C_FLAGS_RELEASE "${OPT_FLAGS} -march=native -Wfatal-errors -fstrict-aliasing") #-fno-inline
+  set(CMAKE_C_FLAGS_RELEASE "-O3 -march=native -Wfatal-errors -fstrict-aliasing") #-fno-inline
   set(CMAKE_EXE_LINKER_FLAGS_DEBUG "-O0")
   set(CMAKE_EXE_LINKER_FLAGS_RELEASE "-O3")