From 147110da842950a6df4b4f8c33f090f5d923d58d Mon Sep 17 00:00:00 2001
From: Matthias Braun <matze@braunis.de>
Date: Tue, 24 Nov 2015 20:06:56 +0000
Subject: [PATCH] LiveVariables should not clobber MachineOperand::IsDead,
 ::IsKill on reserved physical registers

Patch by Nick Johnson <Nicholas.Paul.Johnson@deshawresearch.com>

Differential Revision: http://reviews.llvm.org/D14875

llvm-svn: 254012
---
 llvm/lib/CodeGen/LiveVariables.cpp | 8 ++++++--
 1 file changed, 6 insertions(+), 2 deletions(-)

diff --git a/llvm/lib/CodeGen/LiveVariables.cpp b/llvm/lib/CodeGen/LiveVariables.cpp
index 007f4eb1ae37..06b86d82daf1 100644
--- a/llvm/lib/CodeGen/LiveVariables.cpp
+++ b/llvm/lib/CodeGen/LiveVariables.cpp
@@ -522,11 +522,15 @@ void LiveVariables::runOnInstr(MachineInstr *MI,
       continue;
     unsigned MOReg = MO.getReg();
     if (MO.isUse()) {
-      MO.setIsKill(false);
+      if (!(TargetRegisterInfo::isPhysicalRegister(MOReg) &&
+            MRI->isReserved(MOReg)))
+        MO.setIsKill(false);
       if (MO.readsReg())
         UseRegs.push_back(MOReg);
     } else /*MO.isDef()*/ {
-      MO.setIsDead(false);
+      if (!(TargetRegisterInfo::isPhysicalRegister(MOReg) &&
+            MRI->isReserved(MOReg)))
+        MO.setIsDead(false);
       DefRegs.push_back(MOReg);
     }
   }