--- EMWave2D.old/configure
+++ EMWave2D/configure
@@ -2481,13 +2481,13 @@
   CFLAGS=$ac_save_CFLAGS
 elif test $ac_cv_prog_cc_g = yes; then
   if test "$GCC" = yes; then
-    CFLAGS="-g -O2"
+    CFLAGS="-g -O3"
   else
     CFLAGS="-g"
   fi
 else
   if test "$GCC" = yes; then
-    CFLAGS="-O2"
+    CFLAGS="-O3"
   else
     CFLAGS=
   fi
@@ -3446,13 +3446,13 @@
   CFLAGS=$ac_save_CFLAGS
 elif test $ac_cv_prog_cc_g = yes; then
   if test "$GCC" = yes; then
-    CFLAGS="-g -O2"
+    CFLAGS="-g -O3"
   else
     CFLAGS="-g"
   fi
 else
   if test "$GCC" = yes; then
-    CFLAGS="-O2"
+    CFLAGS="-O3"
   else
     CFLAGS=
   fi
@@ -4284,13 +4284,13 @@
   CFLAGS=$ac_save_CFLAGS
 elif test $ac_cv_prog_cc_g = yes; then
   if test "$GCC" = yes; then
-    CFLAGS="-g -O2"
+    CFLAGS="-g -O3"
   else
     CFLAGS="-g"
   fi
 else
   if test "$GCC" = yes; then
-    CFLAGS="-O2"
+    CFLAGS="-O3"
   else
     CFLAGS=
   fi