Add documentation on sibling call optimization. Rename tailcall2.ll test to sibcall.ll.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@97980 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/docs/LangRef.html b/docs/LangRef.html
index 7cfa052..eec06fc 100644
--- a/docs/LangRef.html
+++ b/docs/LangRef.html
@@ -5149,8 +5149,11 @@
a <a href="#i_ret"><tt>ret</tt></a> instruction. If the "tail" marker is
present, the function call is eligible for tail call optimization,
but <a href="CodeGenerator.html#tailcallopt">might not in fact be
- optimized into a jump</a>. As of this writing, the extra requirements for
- a call to actually be optimized are:
+ optimized into a jump</a>. The code generator may optimize calls marked
+ "tail" with either 1) automatic <a href="CodeGenerator.html#sibcallopt">
+ sibling call optimization</a> when the caller and callee have
+ matching signatures, or 2) forced tail call optimization when the
+ following extra requirements are met:
<ul>
<li>Caller and callee both have the calling
convention <tt>fastcc</tt>.</li>