Fix documentation of -ftree-loop-distibutive-patterns

Fix documentation of -ftree-loop-distibutive-patterns

[Jan Hubicka]

Hi,
we have:

       -ftree-loop-distribute-patterns
           Perform loop distribution of patterns that can be code generated with calls to a library.  This flag is enabled by default at -O2 and higher, and by -fprofile-use and -fauto-profile.

           This pass distributes the initialization loops and generates a call to memset zero.  For example, the loop

...

           and the initialization loop is transformed into a call to memset zero.  This flag is enabled by default at -O3.  It is also enabled by -fprofile-use and -fauto-profile.

Which mentions optimizatoin flags twice and the repeated mention is out of
date, since we enable this option at -O2 as well.

Regtested x86_64-linux, plan to commit it shortly as obvious.

gcc/ChangeLog:

	* doc/invoke.texi (-ftree-loop-distribute-patterns): Remove duplicated
	sentence about optimization flags implying this.

diff --git a/gcc/doc/invoke.texi b/gcc/doc/invoke.texi
index 2a35dc7ac75..27c31ab0c86 100644
--- a/gcc/doc/invoke.texi
+++ b/gcc/doc/invoke.texi
@@ -13852,8 +13852,6 @@ DO I = 1, N
 ENDDO
 @end smallexample
 and the initialization loop is transformed into a call to memset zero.
-This flag is enabled by default at @option{-O3}.
-It is also enabled by @option{-fprofile-use} and @option{-fauto-profile}.
 
 @opindex floop-interchange
 @item -floop-interchange