[commit: ghc] master: Improve -flate-dmd-anal documentation (32ee9b3)

[git at git.haskell.org]

Repository : ssh://git@git.haskell.org/ghc

On branch  : master
Link       : http://ghc.haskell.org/trac/ghc/changeset/32ee9b3ef4f4ab5f6aa1159806d9cb8ca741d811/ghc

>---------------------------------------------------------------

commit 32ee9b3ef4f4ab5f6aa1159806d9cb8ca741d811
Author: Simon Peyton Jones <simonpj at microsoft.com>
Date:   Tue Sep 10 11:38:31 2013 +0100

    Improve -flate-dmd-anal documentation


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32ee9b3ef4f4ab5f6aa1159806d9cb8ca741d811
 docs/users_guide/using.xml |    6 +++++-
 1 file changed, 5 insertions(+), 1 deletion(-)

diff --git a/docs/users_guide/using.xml b/docs/users_guide/using.xml
index b9cbe3e..1a03f2c 100644
--- a/docs/users_guide/using.xml
+++ b/docs/users_guide/using.xml
@@ -2134,7 +2134,11 @@ f "2"    = 2
           </term>
           <listitem>
             <para><emphasis>Off by default.</emphasis>Run demand analysis
-            again, at the end of the simplification pipeline
+            again, at the end of the simplification pipeline.  We found some opportunities
+            for discovering strictness that were not visible earlier; and optimisations like
+            <literal>SpecConstr</literal> can create functions with unused arguments which
+            are eliminated by late demand analysis.  Improvements are modest, but so is the
+            cost.  See notes on the <ulink href="http://ghc.haskell.org/trac/ghc/wiki/LateDmd">Trac wiki page</ulink>.
             </para>
             </listitem>
         </varlistentry>