From a71d62f6e4cc1a38112f267ff203af7d4c4536a8 Mon Sep 17 00:00:00 2001
From: Dan Gohman <gohman@apple.com>
Date: Wed, 14 Apr 2010 16:08:56 +0000
Subject: [PATCH] Add a comment.

llvm-svn: 101248
---
 lib/Analysis/ScalarEvolution.cpp | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/lib/Analysis/ScalarEvolution.cpp b/lib/Analysis/ScalarEvolution.cpp
index a9a444f93a2..b8bcdd41654 100644
--- a/lib/Analysis/ScalarEvolution.cpp
+++ b/lib/Analysis/ScalarEvolution.cpp
@@ -4634,6 +4634,8 @@ ScalarEvolution::HowFarToNonZero(const SCEV *V, const Loop *L) {
 
 /// getLoopPredecessor - If the given loop's header has exactly one unique
 /// predecessor outside the loop, return it. Otherwise return null.
+/// This is less strict that the loop "preheader" concept, which requires
+/// the predecessor to have only one single successor.
 ///
 BasicBlock *ScalarEvolution::getLoopPredecessor(const Loop *L) {
   BasicBlock *Header = L->getHeader();