diff --git a/Makefile.x86_64 b/Makefile.x86_64
index 1b7fe3ef4..d23645058 100644
--- a/Makefile.x86_64
+++ b/Makefile.x86_64
@@ -28,11 +28,15 @@ endif
 ifeq ($(CORE), HASWELL)
 ifndef DYNAMIC_ARCH
 ifndef NO_AVX2
+ifeq ($(C_COMPILER), GCC)
 CCOMMON_OPT += -mavx2
+endif
+ifeq $(F_COMPILER), GFORTRAN)
 FCOMMON_OPT += -mavx2
 endif
 endif
 endif
+endif