diff --git a/configure b/configure
index 694d0b08e98..56867f0081f 100755
--- a/configure
+++ b/configure
@@ -6115,7 +6115,7 @@ fi
 *-darwin*) 
     MKSHLIB='$(CXX) $(CXXFLAGS) $(DSO_PIC_CFLAGS) $(DSO_LDOPTS) -o $@'
     MKCSHLIB='$(CC) $(CFLAGS) $(DSO_PIC_CFLAGS) $(DSO_LDOPTS) -o $@'
-    MOZ_OPTIMIZE_FLAGS="-O2"
+    MOZ_OPTIMIZE_FLAGS="-Os -freorder-blocks -fno-reorder-functions"
     _PEDANTIC=
     CFLAGS="$CFLAGS -fpascal-strings -fno-common"
     CXXFLAGS="$CXXFLAGS -fpascal-strings -fno-common"