diff --git a/Makefile.x86_64 b/Makefile.x86_64
index dbee28079..1b7fe3ef4 100644
--- a/Makefile.x86_64
+++ b/Makefile.x86_64
@@ -25,6 +25,17 @@ endif
 endif
 endif
 
+ifeq ($(CORE), HASWELL)
+ifndef DYNAMIC_ARCH
+ifndef NO_AVX2
+CCOMMON_OPT += -mavx2
+FCOMMON_OPT += -mavx2
+endif
+endif
+endif
+
+
+
 ifeq ($(OSNAME), Interix)
 ARFLAGS		= -m x64
 endif