update documentation


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@35953 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/docs/LangRef.html b/docs/LangRef.html
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--- a/docs/LangRef.html
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@@ -603,8 +603,10 @@
 <p>Global variables define regions of memory allocated at compilation time
 instead of run-time.  Global variables may optionally be initialized, may have
 an explicit section to be placed in, and may
-have an optional explicit alignment specified.  A
-variable may be defined as a global "constant," which indicates that the
+have an optional explicit alignment specified.  A variable may be defined as
+"thread_local", which means that it will not be shared by threads (each thread
+will have a separated copy of the variable).
+A variable may be defined as a global "constant," which indicates that the
 contents of the variable will <b>never</b> be modified (enabling better
 optimization, allowing the global data to be placed in the read-only section of
 an executable, etc).  Note that variables that need runtime initialization