From 3ac8cd614f5c5accb346d584e167c1ea99c069ae Mon Sep 17 00:00:00 2001
From: Dan Gohman <gohman@apple.com>
Date: Mon, 24 Jan 2011 17:54:18 +0000
Subject: [PATCH] Add a comment.

llvm-svn: 124126
---
 llvm/lib/Analysis/ScalarEvolution.cpp | 1 +
 1 file changed, 1 insertion(+)

diff --git a/llvm/lib/Analysis/ScalarEvolution.cpp b/llvm/lib/Analysis/ScalarEvolution.cpp
index e3fcb8428e82..c10af50dd597 100644
--- a/llvm/lib/Analysis/ScalarEvolution.cpp
+++ b/llvm/lib/Analysis/ScalarEvolution.cpp
@@ -3126,6 +3126,7 @@ ScalarEvolution::getUnsignedRange(const SCEV *S) {
 ///
 ConstantRange
 ScalarEvolution::getSignedRange(const SCEV *S) {
+  // See if we've computed this range already.
   DenseMap<const SCEV *, ConstantRange>::iterator I = SignedRanges.find(S);
   if (I != SignedRanges.end())
     return I->second;