diff --git a/m4/ax_cc_maxopt.m4 b/m4/ax_cc_maxopt.m4
index cbe4d7c0d5bf764784ede9e47ca030ad688c1405..7523d9d09ee741914fe9fe1cb22d3e0550763233 100644
--- a/m4/ax_cc_maxopt.m4
+++ b/m4/ax_cc_maxopt.m4
@@ -105,7 +105,7 @@ if test "$ac_test_CFLAGS" != "set"; then
                 echo "******************************************************"])
          ;;
 
-    intel) CFLAGS="-O3 -ansi_alias"
+    intel) CFLAGS="-O3 -ansi-alias"
 	if test "x$acx_maxopt_portable" = xno; then
 	  icc_archflag=unknown
 	  icc_flags=""