From 8dc8a8d8af69cdb04f84377957d7b6b5674f9bb9 Mon Sep 17 00:00:00 2001
From: Evan Cheng <evan.cheng@apple.com>
Date: Wed, 16 Apr 2008 18:01:08 +0000
Subject: [PATCH] Empty basic block should have an empty range.

llvm-svn: 49800
---
 llvm/lib/CodeGen/LiveIntervalAnalysis.cpp | 4 +++-
 1 file changed, 3 insertions(+), 1 deletion(-)

diff --git a/llvm/lib/CodeGen/LiveIntervalAnalysis.cpp b/llvm/lib/CodeGen/LiveIntervalAnalysis.cpp
index 9f72035bc905..d8ca141c6693 100644
--- a/llvm/lib/CodeGen/LiveIntervalAnalysis.cpp
+++ b/llvm/lib/CodeGen/LiveIntervalAnalysis.cpp
@@ -108,7 +108,9 @@ bool LiveIntervals::runOnMachineFunction(MachineFunction &fn) {
     }
 
     // Set the MBB2IdxMap entry for this MBB.
-    MBB2IdxMap[MBB->getNumber()] = std::make_pair(StartIdx, MIIndex - 1);
+    MBB2IdxMap[MBB->getNumber()] = (StartIdx == MIIndex)
+      ? std::make_pair(StartIdx, StartIdx)  // Empty MBB
+      : std::make_pair(StartIdx, MIIndex - 1);
     Idx2MBBMap.push_back(std::make_pair(StartIdx, MBB));
   }
   std::sort(Idx2MBBMap.begin(), Idx2MBBMap.end(), Idx2MBBCompare());
-- 
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