[commit: ghc] master: Document the fact that cmm dumps won't show unreachable blocks. (36091ec)

[git at git.haskell.org]

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

On branch  : master
Link       : http://ghc.haskell.org/trac/ghc/changeset/36091ec94e85d871b12b07e69c1589224d1dd7e2/ghc

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

commit 36091ec94e85d871b12b07e69c1589224d1dd7e2
Author: klebinger.andreas at gmx.at <klebinger.andreas at gmx.at>
Date:   Mon Jun 4 13:26:22 2018 -0400

    Document the fact that cmm dumps won't show unreachable blocks.
    
    Reviewers: bgamari
    
    Reviewed By: bgamari
    
    Subscribers: rwbarton, thomie, carter
    
    Differential Revision: https://phabricator.haskell.org/D4788


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36091ec94e85d871b12b07e69c1589224d1dd7e2
 docs/users_guide/debugging.rst | 3 +++
 1 file changed, 3 insertions(+)

diff --git a/docs/users_guide/debugging.rst b/docs/users_guide/debugging.rst
index 7adcc84..a3f0be7 100644
--- a/docs/users_guide/debugging.rst
+++ b/docs/users_guide/debugging.rst
@@ -382,6 +382,9 @@ These flags dump various phases of GHC's C-\\- pipeline.
     ``.cmm`` compilation this also dumps the result of
     file parsing.
 
+    Cmm dumps don't include unreachable blocks since we print
+    blocks in reverse post order.
+
 .. ghc-flag:: -ddump-cmm-from-stg
     :shortdesc: Dump STG-to-C-\\- output
     :type: dynamic