update 6.2 -> current failed - optimization problem

ussr# make buildworld
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 >>> World build started on Wed Jun 27 23:48:21 MSD 2007
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--------------------------------------------------------------
 >>> Rebuilding the temporary build tree
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rm -rf /usr/obj/usr/src/tmp
rm -rf /usr/obj/usr/src/lib32
mkdir -p /usr/obj/usr/src/tmp/legacy/usr/bin
mkdir -p /usr/obj/usr/src/tmp/legacy/usr/games
mkdir -p /usr/obj/usr/src/tmp/legacy/usr/include/sys
mkdir -p /usr/obj/usr/src/tmp/legacy/usr/lib
mkdir -p /usr/obj/usr/src/tmp/legacy/usr/libexec
mkdir -p /usr/obj/usr/src/tmp/legacy/usr/sbin
mkdir -p /usr/obj/usr/src/tmp/legacy/usr/share/dict
mkdir -p /usr/obj/usr/src/tmp/legacy/usr/share/groff_font/devX100
mkdir -p /usr/obj/usr/src/tmp/legacy/usr/share/groff_font/devX100-12
mkdir -p /usr/obj/usr/src/tmp/legacy/usr/share/groff_font/devX75
mkdir -p /usr/obj/usr/src/tmp/legacy/usr/share/groff_font/devX75-12
mkdir -p /usr/obj/usr/src/tmp/legacy/usr/share/groff_font/devascii
mkdir -p /usr/obj/usr/src/tmp/legacy/usr/share/groff_font/devcp1047
mkdir -p /usr/obj/usr/src/tmp/legacy/usr/share/groff_font/devdvi
mkdir -p /usr/obj/usr/src/tmp/legacy/usr/share/groff_font/devhtml
mkdir -p /usr/obj/usr/src/tmp/legacy/usr/share/groff_font/devkoi8-r
mkdir -p /usr/obj/usr/src/tmp/legacy/usr/share/groff_font/devlatin1
mkdir -p /usr/obj/usr/src/tmp/legacy/usr/share/groff_font/devlbp
mkdir -p /usr/obj/usr/src/tmp/legacy/usr/share/groff_font/devlj4
mkdir -p /usr/obj/usr/src/tmp/legacy/usr/share/groff_font/devps
mkdir -p /usr/obj/usr/src/tmp/legacy/usr/share/groff_font/devutf8
mkdir -p /usr/obj/usr/src/tmp/legacy/usr/share/tmac/mdoc
mkdir -p /usr/obj/usr/src/tmp/legacy/usr/share/tmac/mm
mkdir -p /usr/obj/usr/src/tmp/lib
mkdir -p /usr/obj/usr/src/tmp/usr/bin
mkdir -p /usr/obj/usr/src/tmp/usr/include
mkdir -p /usr/obj/usr/src/tmp/usr/lib/compat/aout
mkdir -p /usr/obj/usr/src/tmp/usr/libdata/ldscripts
mkdir -p /usr/obj/usr/src/tmp/usr/libexec
mkdir -p /usr/obj/usr/src/tmp/usr/sbin
mkdir -p /usr/obj/usr/src/tmp/usr/share/misc
mkdir -p /usr/obj/usr/src/tmp/usr/share/snmp/defs
mkdir -p /usr/obj/usr/src/tmp/usr/share/snmp/mibs
mtree -deU -f /usr/src/etc/mtree/BSD.include.dist  -p 
/usr/obj/usr/src/tmp/usr/include >/dev/null
ln -sf /usr/src/sys /usr/obj/usr/src/tmp

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 >>> stage 1.1: legacy release compatibility shims
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cd /usr/src; MAKEOBJDIRPREFIX=/usr/obj/usr/src/tmp  INSTALL="sh 
/usr/src/tools/install.sh"  
PATH=/usr/obj/usr/src/tmp/legacy/usr/sbin:/usr/obj/usr/src/tmp/legacy/usr/bin:/usr/obj/usr/src/tmp/legacy/usr/games:/sbin:/bin:/usr/sbin:/usr/bin  
WORLDTMP=/usr/obj/usr/src/tmp  MAKEFLAGS="-m /usr/src/tools/build/mk  -m 
/usr/src/share/mk" make -f Makefile.inc1  DESTDIR=  
BOOTSTRAPPING=602000  -DWITHOUT_HTML -DWITHOUT_INFO -DNO_LINT 
-DWITHOUT_MAN  -DWITHOUT_NLS -DNO_PIC -DWITHOUT_PROFILE -DNO_SHARED  
-DNO_CPU_CFLAGS -DNO_WARNS legacy
===> tools/build (obj,includes,depend,all,install)
/usr/obj/usr/src/tmp/usr/src/tools/build created for /usr/src/tools/build
cd /usr/src/tools/build; make buildincludes; make installincludes
rm -f .depend
mkdep -f .depend -a    -I/usr/obj/usr/src/tmp/legacy/usr/include 
/usr/src/tools/build/dummy.c
cc -O2 -fno-strict-aliasing -fno-tree-vrp -pipe  
-I/usr/obj/usr/src/tmp/legacy/usr/include -c /usr/src/tools/build/dummy.c
cc1: error: unrecognized command line option "-fno-tree-vrp"
*** Error code 1

Stop in /usr/src/tools/build.
*** Error code 1

Stop in /usr/src.
*** Error code 1

Stop in /usr/src.
*** Error code 1

Stop in /usr/src.
ussr# pwd
/usr/src
ussr#            
ussr# uname -a
FreeBSD ussr.lissyara.int.otradno.ru 6.2-RELEASE FreeBSD 6.2-RELEASE #0: 
Fri Jan 12 08:43:30 UTC 2007     
root_at_portnoy.cse.buffalo.edu:/usr/obj/usr/src/sys/SMP  amd64
ussr#            
============================
if add to make.conf
CFLAGS=-O
then update success
=========
may be add this to /usr/src/UPDATING?