From: Lang Hames <lhames@gmail.com>
Date: Wed, 15 Feb 2012 01:31:10 +0000 (+0000)
Subject: Don't emit live ranges for physregs live-ins that are dead.
X-Git-Url: http://demsky.eecs.uci.edu/git/?a=commitdiff_plain;h=f58e37f957191a3e41f605628c6169fbb1d4f922;p=oota-llvm.git

Don't emit live ranges for physregs live-ins that are dead.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@150553 91177308-0d34-0410-b5e6-96231b3b80d8
---

diff --git a/lib/CodeGen/LiveIntervalAnalysis.cpp b/lib/CodeGen/LiveIntervalAnalysis.cpp
index d27b8e5fd9f..f99f8cfbc93 100644
--- a/lib/CodeGen/LiveIntervalAnalysis.cpp
+++ b/lib/CodeGen/LiveIntervalAnalysis.cpp
@@ -529,9 +529,10 @@ void LiveIntervals::handleLiveInRegister(MachineBasicBlock *MBB,
   if (!SeenDefUse) {
     if (isAllocatable(interval.reg) || isReserved(interval.reg)) {
       // This must be an entry block or landing pad - we asserted so on entry
-      // to the function. For these blocks the interval is dead on entry.
+      // to the function. For these blocks the interval is dead on entry, so
+      // we won't emit a live-range for it.
       DEBUG(dbgs() << " dead");
-      end = start.getDeadSlot();
+      return;
     } else {
       assert(isRegLiveOutOf(MBB, interval.reg) &&
              "Live in reg untouched in block should be be live through.");