Fix -fsplit-paths documentation

It is enabled at -O3, but the doc currently says -O2.  This fixes it.


	* doc/invoke.texi (-fsplit-paths): This is enabled by default at -O3.

From-SVN: r268170

gcc/ChangeLog

+2019-01-22  Segher Boessenkool  <segher@kernel.crashing.org>
+
+	* doc/invoke.texi (-fsplit-paths): This is enabled by default at -O3.
+
 2019-01-22  Jakub Jelinek  <jakub@redhat.com>
 
 	PR target/88965

gcc/doc/invoke.texi

@@ -9746,7 +9746,7 @@ enabled.
 @opindex fsplit-paths
 Split paths leading to loop backedges.  This can improve dead code
 elimination and common subexpression elimination.  This is enabled by
-default at @option{-O2} and above.
+default at @option{-O3} and above.
 
 @item -fsplit-ivs-in-unroller
 @opindex fsplit-ivs-in-unroller