Make sure compiler does not optimize away calls to math functions

1 files changed, 9 insertions, 2 deletions

diff --git a/cmake/FindStandardMathLibrary.cmake b/cmake/FindStandardMathLibrary.cmake
index fc4728a82..b174cbb4f 100644
--- a/cmake/FindStandardMathLibrary.cmake
+++ b/cmake/FindStandardMathLibrary.cmake
@@ -10,6 +10,7 @@
 #                               pass the "-lm" linker flag.
 #
 # Copyright (c) 2010 Benoit Jacob <jacob.benoit.1@gmail.com>
+#               2020 Susi Lehtola <susi.lehtola@gmail.com>
 # Redistribution and use is allowed according to the terms of the 2-clause BSD license.
 
 
@@ -19,9 +20,15 @@ include(CheckCXXSourceCompiles)
 # notice the std:: is required on some platforms such as QNX
 # notice the (void) is required if -Wall (-Wunused-value) is added to CMAKE_CXX_FLAG
 
+# We read in the arguments from standard input to avoid the compiler optimizing away the calls
 set(find_standard_math_library_test_program
-"#include<cmath>
-int main() { (void)std::sin(0.0); (void)std::log(0.0f); }")
+"
+#include<cmath>
+int main(int argc, char **argv) {
+  (void)std::sin(argc));
+  (void)std::log(argc));
+  return 0;
+}")
 
 # first try compiling/linking the test program without any linker flags