free(null) -> noop


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@49972 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/docs/LangRef.html b/docs/LangRef.html
index 09e557f..a638e50 100644
--- a/docs/LangRef.html
+++ b/docs/LangRef.html
@@ -2842,8 +2842,8 @@
 <h5>Semantics:</h5>
 
 <p>Access to the memory pointed to by the pointer is no longer defined
-after this instruction executes.  If the pointer is null, the behavior is
-undefined.</p>
+after this instruction executes.  If the pointer is null, the operation
+is a noop.</p>
 
 <h5>Example:</h5>