[Lexicon] Add GVN

Summary: Add a lexicon entry for global value numbering.

Reviewers: davide, majnemer

Reviewed By: davide

Subscribers: llvm-commits, inouehrs

Differential Revision: https://reviews.llvm.org/D33664

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@305270 91177308-0d34-0410-b5e6-96231b3b80d8

diff --git a/docs/Lexicon.rst b/docs/Lexicon.rst
index ebc3fb772e81b83cde3580435d90091552434a71..ce7ed318fe4b6082bae409a12832a7131595085a 100644 (file)
--- a/docs/Lexicon.rst
+++ b/docs/Lexicon.rst
@@ -109,6 +109,13 @@ G
     Garbage Collection. The practice of using reachability analysis instead of
     explicit memory management to reclaim unused memory.
 
+**GVN**
+    Global Value Numbering. GVN is a pass that partitions values computed by a
+    function into congruence classes. Values ending up in the same congruence
+    class are guaranteed to be the same for every execution of the program.
+    In that respect, congruency is a compile-time approximation of equivalence
+    of values at runtime.
+
 H
 -