invoke.texi (Optimize Options): Reword introduction a bit.

	* doc/invoke.texi (Optimize Options): Reword introduction a bit.

Co-Authored-By: Alexander Monakov <amonakov@ispras.ru>

From-SVN: r155578

gcc/ChangeLog

+2010-01-02  Gerald Pfeifer  <gerald@pfeifer.com>
+            Alexander Monakov  <amonakov@ispras.ru>
+
+	* doc/invoke.texi (Optimize Options): Reword introduction a bit.
+
 2010-01-02  Richard Guenther  <rguenther@suse.de>
 
 	PR middle-end/42577

gcc/doc/invoke.texi

@@ -5666,8 +5666,9 @@ each of them.
 Not all optimizations are controlled directly by a flag.  Only
 optimizations that have a flag are listed in this section.
 
-Most of the optimizations are not enabled if a @option{-O} level is not set on
-the command line, even if individual optimization flags are specified.
+Most optimizations are only enabled if an @option{-O} level is set on
+the command line.  Otherwise they are disabled, even if individual             
+optimization flags are specified.
 
 Depending on the target and how GCC was configured, a slightly different
 set of optimizations may be enabled at each @option{-O} level than