From bef4c3e069a66c8b2d5871468cb57978f44ddc54 Mon Sep 17 00:00:00 2001
From: Andrew Trick <atrick@apple.com>
Date: Thu, 25 Jul 2013 18:35:22 +0000
Subject: [PATCH] RegAllocGreedy comment.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@187141 91177308-0d34-0410-b5e6-96231b3b80d8
---
 lib/CodeGen/RegAllocGreedy.cpp | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/lib/CodeGen/RegAllocGreedy.cpp b/lib/CodeGen/RegAllocGreedy.cpp
index 79253715c33..87b11a5f51c 100644
--- a/lib/CodeGen/RegAllocGreedy.cpp
+++ b/lib/CodeGen/RegAllocGreedy.cpp
@@ -434,7 +434,8 @@ void RAGreedy::enqueue(LiveInterval *LI) {
     if (VRM->hasKnownPreference(Reg))
       Prio |= (1u << 30);
   }
-
+  // The virtual register number is a tie breaker for same-sized ranges.
+  // Give lower vreg numbers higher priority to assign them first.
   Queue.push(std::make_pair(Prio, ~Reg));
 }