From 81d686edbe6effe624add9394673bd571d89bfb7 Mon Sep 17 00:00:00 2001
From: Jakob Stoklund Olesen <stoklund@2pi.dk>
Date: Sun, 24 Jul 2011 20:33:23 +0000
Subject: [PATCH] Never extend live ranges for <undef> uses.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@135886 91177308-0d34-0410-b5e6-96231b3b80d8
---
 lib/CodeGen/SplitKit.cpp | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/lib/CodeGen/SplitKit.cpp b/lib/CodeGen/SplitKit.cpp
index 46a43d8bd72..2197046b030 100644
--- a/lib/CodeGen/SplitKit.cpp
+++ b/lib/CodeGen/SplitKit.cpp
@@ -952,7 +952,7 @@ void SplitEditor::rewriteAssigned(bool ExtendRanges) {
                  << Idx << ':' << RegIdx << '\t' << *MI);
 
     // Extend liveness to Idx if the instruction reads reg.
-    if (!ExtendRanges)
+    if (!ExtendRanges || MO.isUndef())
       continue;
 
     // Skip instructions that don't read Reg.