*** a/config/c-compiler.m4
--- b/config/c-compiler.m4
***************
*** 242,247 **** undefine([Ac_cachevar])dnl
--- 242,271 ----
  
  
  
+ # PGAC_PROG_CC_CFLAGS_EXTRA_OPT
+ # -----------------------
+ # Given a string, check if the compiler supports the string as a
+ # command-line option. If it does, add the string to CFLAGS_EXTRA.
+ AC_DEFUN([PGAC_PROG_CC_CFLAGS_EXTRA_OPT],
+ [define([Ac_cachevar], [AS_TR_SH([pgac_cv_prog_cc_cflags_extra_$1])])dnl
+ AC_CACHE_CHECK([whether $CC supports $1], [Ac_cachevar],
+ [pgac_save_CFLAGS_EXTRA=$CFLAGS_EXTRA
+ CFLAGS_EXTRA="$pgac_save_CFLAGS_EXTRA $1"
+ ac_save_c_werror_flag=$ac_c_werror_flag
+ ac_c_werror_flag=yes
+ _AC_COMPILE_IFELSE([AC_LANG_PROGRAM()],
+                    [Ac_cachevar=yes],
+                    [Ac_cachevar=no])
+ ac_c_werror_flag=$ac_save_c_werror_flag
+ CFLAGS_EXTRA="$pgac_save_CFLAGS_EXTRA"])
+ if test x"$Ac_cachevar" = x"yes"; then
+   CFLAGS_EXTRA="$CFLAGS_EXTRA $1"
+ fi
+ undefine([Ac_cachevar])dnl
+ ])# PGAC_PROG_CC_CFLAGS_EXTRA_OPT
+ 
+ 
+ 
  # PGAC_PROG_CC_LDFLAGS_OPT
  # ------------------------
  # Given a string, check if the compiler supports the string as a
*** a/configure
--- b/configure
***************
*** 731,736 **** autodepend
--- 731,737 ----
  TAS
  GCC
  CPP
+ CFLAGS_EXTRA
  SUN_STUDIO_CC
  OBJEXT
  EXEEXT
***************
*** 3944,3949 **** else
--- 3945,3955 ----
    fi
  fi
  
+ # set CFLAGS_EXTRA from the environment, if available
+ if test "$ac_env_CFLAGS_EXTRA_set" = set; then
+   CFLAGS_EXTRA=$ac_env_CFLAGS_EXTRA_value
+ fi
+ 
  # Some versions of GCC support some additional useful warning flags.
  # Check whether they are supported, and add them to CFLAGS if so.
  # ICC pretends to be GCC but it's lying; it doesn't support these flags,
***************
*** 4376,4381 **** if test x"$pgac_cv_prog_cc_cflags__fexcess_precision_standard" = x"yes"; then
--- 4382,4508 ----
    CFLAGS="$CFLAGS -fexcess-precision=standard"
  fi
  
+   # Optimization flags in $CFLAGS_EXTRA should only be applied to specific files
+   { $as_echo "$as_me:$LINENO: checking whether $CC supports -funroll-loops" >&5
+ $as_echo_n "checking whether $CC supports -funroll-loops... " >&6; }
+ if test "${pgac_cv_prog_cc_cflags_extra__funroll_loops+set}" = set; then
+   $as_echo_n "(cached) " >&6
+ else
+   pgac_save_CFLAGS_EXTRA=$CFLAGS_EXTRA
+ CFLAGS_EXTRA="$pgac_save_CFLAGS_EXTRA -funroll-loops"
+ ac_save_c_werror_flag=$ac_c_werror_flag
+ ac_c_werror_flag=yes
+ cat >conftest.$ac_ext <<_ACEOF
+ /* confdefs.h.  */
+ _ACEOF
+ cat confdefs.h >>conftest.$ac_ext
+ cat >>conftest.$ac_ext <<_ACEOF
+ /* end confdefs.h.  */
+ 
+ int
+ main ()
+ {
+ 
+   ;
+   return 0;
+ }
+ _ACEOF
+ rm -f conftest.$ac_objext
+ if { (ac_try="$ac_compile"
+ case "(($ac_try" in
+   *\"* | *\`* | *\\*) ac_try_echo=\$ac_try;;
+   *) ac_try_echo=$ac_try;;
+ esac
+ eval ac_try_echo="\"\$as_me:$LINENO: $ac_try_echo\""
+ $as_echo "$ac_try_echo") >&5
+   (eval "$ac_compile") 2>conftest.er1
+   ac_status=$?
+   grep -v '^ *+' conftest.er1 >conftest.err
+   rm -f conftest.er1
+   cat conftest.err >&5
+   $as_echo "$as_me:$LINENO: \$? = $ac_status" >&5
+   (exit $ac_status); } && {
+ 	 test -z "$ac_c_werror_flag" ||
+ 	 test ! -s conftest.err
+        } && test -s conftest.$ac_objext; then
+   pgac_cv_prog_cc_cflags_extra__funroll_loops=yes
+ else
+   $as_echo "$as_me: failed program was:" >&5
+ sed 's/^/| /' conftest.$ac_ext >&5
+ 
+ 	pgac_cv_prog_cc_cflags_extra__funroll_loops=no
+ fi
+ 
+ rm -f core conftest.err conftest.$ac_objext conftest.$ac_ext
+ ac_c_werror_flag=$ac_save_c_werror_flag
+ CFLAGS_EXTRA="$pgac_save_CFLAGS_EXTRA"
+ fi
+ { $as_echo "$as_me:$LINENO: result: $pgac_cv_prog_cc_cflags_extra__funroll_loops" >&5
+ $as_echo "$pgac_cv_prog_cc_cflags_extra__funroll_loops" >&6; }
+ if test x"$pgac_cv_prog_cc_cflags_extra__funroll_loops" = x"yes"; then
+   CFLAGS_EXTRA="$CFLAGS_EXTRA -funroll-loops"
+ fi
+ 
+   { $as_echo "$as_me:$LINENO: checking whether $CC supports -ftree-vectorize" >&5
+ $as_echo_n "checking whether $CC supports -ftree-vectorize... " >&6; }
+ if test "${pgac_cv_prog_cc_cflags_extra__ftree_vectorize+set}" = set; then
+   $as_echo_n "(cached) " >&6
+ else
+   pgac_save_CFLAGS_EXTRA=$CFLAGS_EXTRA
+ CFLAGS_EXTRA="$pgac_save_CFLAGS_EXTRA -ftree-vectorize"
+ ac_save_c_werror_flag=$ac_c_werror_flag
+ ac_c_werror_flag=yes
+ cat >conftest.$ac_ext <<_ACEOF
+ /* confdefs.h.  */
+ _ACEOF
+ cat confdefs.h >>conftest.$ac_ext
+ cat >>conftest.$ac_ext <<_ACEOF
+ /* end confdefs.h.  */
+ 
+ int
+ main ()
+ {
+ 
+   ;
+   return 0;
+ }
+ _ACEOF
+ rm -f conftest.$ac_objext
+ if { (ac_try="$ac_compile"
+ case "(($ac_try" in
+   *\"* | *\`* | *\\*) ac_try_echo=\$ac_try;;
+   *) ac_try_echo=$ac_try;;
+ esac
+ eval ac_try_echo="\"\$as_me:$LINENO: $ac_try_echo\""
+ $as_echo "$ac_try_echo") >&5
+   (eval "$ac_compile") 2>conftest.er1
+   ac_status=$?
+   grep -v '^ *+' conftest.er1 >conftest.err
+   rm -f conftest.er1
+   cat conftest.err >&5
+   $as_echo "$as_me:$LINENO: \$? = $ac_status" >&5
+   (exit $ac_status); } && {
+ 	 test -z "$ac_c_werror_flag" ||
+ 	 test ! -s conftest.err
+        } && test -s conftest.$ac_objext; then
+   pgac_cv_prog_cc_cflags_extra__ftree_vectorize=yes
+ else
+   $as_echo "$as_me: failed program was:" >&5
+ sed 's/^/| /' conftest.$ac_ext >&5
+ 
+ 	pgac_cv_prog_cc_cflags_extra__ftree_vectorize=no
+ fi
+ 
+ rm -f core conftest.err conftest.$ac_objext conftest.$ac_ext
+ ac_c_werror_flag=$ac_save_c_werror_flag
+ CFLAGS_EXTRA="$pgac_save_CFLAGS_EXTRA"
+ fi
+ { $as_echo "$as_me:$LINENO: result: $pgac_cv_prog_cc_cflags_extra__ftree_vectorize" >&5
+ $as_echo "$pgac_cv_prog_cc_cflags_extra__ftree_vectorize" >&6; }
+ if test x"$pgac_cv_prog_cc_cflags_extra__ftree_vectorize" = x"yes"; then
+   CFLAGS_EXTRA="$CFLAGS_EXTRA -ftree-vectorize"
+ fi
+ 
  elif test "$ICC" = yes; then
    # Intel's compiler has a bug/misoptimization in checking for
    # division by NAN (NaN == 0), -mp1 fixes it, so add it to the CFLAGS.
***************
*** 4627,4632 **** fi
--- 4754,4762 ----
  
  fi
  
+ CFLAGS_EXTRA=$CFLAGS_EXTRA
+ 
+ 
  # supply -g if --enable-debug
  if test "$enable_debug" = yes && test "$ac_cv_prog_cc_g" = yes; then
    CFLAGS="$CFLAGS -g"
*** a/configure.in
--- b/configure.in
***************
*** 400,405 **** else
--- 400,410 ----
    fi
  fi
  
+ # set CFLAGS_EXTRA from the environment, if available
+ if test "$ac_env_CFLAGS_EXTRA_set" = set; then
+   CFLAGS_EXTRA=$ac_env_CFLAGS_EXTRA_value
+ fi
+ 
  # Some versions of GCC support some additional useful warning flags.
  # Check whether they are supported, and add them to CFLAGS if so.
  # ICC pretends to be GCC but it's lying; it doesn't support these flags,
***************
*** 419,424 **** if test "$GCC" = yes -a "$ICC" = no; then
--- 424,432 ----
    PGAC_PROG_CC_CFLAGS_OPT([-fwrapv])
    # Disable FP optimizations that cause various errors on gcc 4.5+ or maybe 4.6+
    PGAC_PROG_CC_CFLAGS_OPT([-fexcess-precision=standard])
+   # Optimization flags in $CFLAGS_EXTRA should only be applied to specific files
+   PGAC_PROG_CC_CFLAGS_EXTRA_OPT([-funroll-loops])
+   PGAC_PROG_CC_CFLAGS_EXTRA_OPT([-ftree-vectorize])
  elif test "$ICC" = yes; then
    # Intel's compiler has a bug/misoptimization in checking for
    # division by NAN (NaN == 0), -mp1 fixes it, so add it to the CFLAGS.
***************
*** 434,439 **** elif test "$PORTNAME" = "hpux"; then
--- 442,449 ----
    PGAC_PROG_CC_CFLAGS_OPT([+Olibmerrno])
  fi
  
+ AC_SUBST(CFLAGS_EXTRA, $CFLAGS_EXTRA)
+ 
  # supply -g if --enable-debug
  if test "$enable_debug" = yes && test "$ac_cv_prog_cc_g" = yes; then
    CFLAGS="$CFLAGS -g"
*** a/src/Makefile.global.in
--- b/src/Makefile.global.in
***************
*** 219,224 **** CC = @CC@
--- 219,225 ----
  GCC = @GCC@
  SUN_STUDIO_CC = @SUN_STUDIO_CC@
  CFLAGS = @CFLAGS@
+ CFLAGS_EXTRA = @CFLAGS_EXTRA@
  
  # Kind-of compilers
  
*** a/src/backend/storage/page/Makefile
--- b/src/backend/storage/page/Makefile
***************
*** 15,17 **** include $(top_builddir)/src/Makefile.global
--- 15,20 ----
  OBJS =  bufpage.o checksum.o itemptr.o
  
  include $(top_srcdir)/src/backend/common.mk
+ 
+ # important optimizations flags for checksum.c
+ checksum.o: CFLAGS += ${CFLAGS_EXTRA}