From 5b200d8a133a07af1f7802025bd5a58a1cdd544d Mon Sep 17 00:00:00 2001
From: Dan Gohman <gohman@apple.com>
Date: Fri, 19 Dec 2008 00:45:13 +0000
Subject: [PATCH] Fix RegScavenger::forward() to work on basic blocks
 containing exactly one instruction.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@61236 91177308-0d34-0410-b5e6-96231b3b80d8
---
 include/llvm/CodeGen/RegisterScavenging.h | 1 +
 1 file changed, 1 insertion(+)

diff --git a/include/llvm/CodeGen/RegisterScavenging.h b/include/llvm/CodeGen/RegisterScavenging.h
index 40dd66c06a7..05e9e55e234 100644
--- a/include/llvm/CodeGen/RegisterScavenging.h
+++ b/include/llvm/CodeGen/RegisterScavenging.h
@@ -98,6 +98,7 @@ public:
   /// forward / backward - Move the internal MBB iterator and update register
   /// states until it has processed the specific iterator.
   void forward(MachineBasicBlock::iterator I) {
+    if (!Tracking && MBB->begin() != I) forward();
     while (MBBI != I) forward();
   }
   void backward(MachineBasicBlock::iterator I) {