Add a comment describing natural loops.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@82859 91177308-0d34-0410-b5e6-96231b3b80d8

diff --git a/include/llvm/Analysis/LoopInfo.h b/include/llvm/Analysis/LoopInfo.h
index a928ccdb8ef2b40faeb9294b6d35fdb23bf6a15d..bed7608b11e4bcdd0b1f4f31677f7f702b618c8f 100644 (file)
--- a/include/llvm/Analysis/LoopInfo.h
+++ b/include/llvm/Analysis/LoopInfo.h
@@ -8,7 +8,8 @@
 //===----------------------------------------------------------------------===//
 //
 // This file defines the LoopInfo class that is used to identify natural loops
-// and determine the loop depth of various nodes of the CFG.  Note that natural
+// and determine the loop depth of various nodes of the CFG.  A natural loop
+// has exactly one entry-point, which is called the header. Note that natural
 // loops may actually be several loops that share the same header node.
 //
 // This analysis calculates the nesting structure of loops in a function.  For