diff -urN a/configure.ac b/configure.ac
--- a/configure.ac	2014-02-25 18:49:15.000000000 -0600
+++ b/configure.ac	2014-03-07 18:19:53.718147847 -0600
@@ -639,23 +639,6 @@
   AC_DEFINE([JEMALLOC_IVSALLOC], [ ])
 fi
 
-dnl Only optimize if not debugging.
-if test "x$enable_debug" = "x0" -a "x$no_CFLAGS" = "xyes" ; then
-  dnl Make sure that an optimization flag was not specified in EXTRA_CFLAGS.
-  optimize="no"
-  echo "$CFLAGS $EXTRA_CFLAGS" | grep '\-O' >/dev/null || optimize="yes"
-  if test "x${optimize}" = "xyes" ; then
-    if test "x$GCC" = "xyes" ; then
-      JE_CFLAGS_APPEND([-O3])
-      JE_CFLAGS_APPEND([-funroll-loops])
-    elif test "x$je_cv_msvc" = "xyes" ; then
-      JE_CFLAGS_APPEND([-O2])
-    else
-      JE_CFLAGS_APPEND([-O])
-    fi
-  fi
-fi
-
 dnl Enable statistics calculation by default.
 AC_ARG_ENABLE([stats],
   [AS_HELP_STRING([--disable-stats],
