diff --git a/tests/Test_simd.cc b/tests/Test_simd.cc
index abec2410..c0bbef1d 100644
--- a/tests/Test_simd.cc
+++ b/tests/Test_simd.cc
@@ -725,6 +725,7 @@ int main (int argc, char ** argv)
     std::cout <<" OK ! "<<std::endl;
 
     // Double to Half
+#ifdef USE_FP16
     std::cout << GridLogMessage<< "Double to half" ;
     precisionChange(&H[0],&D[0],Ndp);
     precisionChange(&DD[0],&H[0],Ndp);
@@ -753,7 +754,7 @@ int main (int argc, char ** argv)
       assert( tmp < 1.0e-3 ); 
     }
     std::cout <<" OK ! "<<std::endl;
-
+#endif
   }
   Grid_finalize();
 }