MFC r237406:

MFC	r237406:

Bring a couple of fixes for gcc optimizations.

The GCC4.3 branch contains some optimization fixes
that were not considered regressions and therefore
were never backported. We are bringing a couple of
them that are under GPLv2 since they were made
before the license switch upstream.

git-svn-id: svn://svn.freebsd.org/base/stable/8@237679 ccf9f872-aa2e-dd11-9fc8-001c23d0bc1f