diff -urN a/Lib/distutils/cygwinccompiler.py b/Lib/distutils/cygwinccompiler.py
--- a/Lib/distutils/cygwinccompiler.py	2014-10-11 22:44:44.871007400 +0100
+++ b/Lib/distutils/cygwinccompiler.py	2014-10-11 22:44:47.486157000 +0100
@@ -330,9 +330,9 @@
         else:
             no_cygwin = ''
 
-        self.set_executables(compiler='gcc%s -O -Wall' % no_cygwin,
-                             compiler_so='gcc%s -mdll -O -Wall' % no_cygwin,
-                             compiler_cxx='g++%s -O -Wall' % no_cygwin,
+        self.set_executables(compiler='gcc%s -O2 -Wall' % no_cygwin,
+                             compiler_so='gcc%s -mdll -O2 -Wall' % no_cygwin,
+                             compiler_cxx='g++%s -O2 -Wall' % no_cygwin,
                              linker_exe='gcc%s' % no_cygwin,
                              linker_so='%s%s %s %s'
                                     % (self.linker_dll, no_cygwin,