Don't spill dead def.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@51305 91177308-0d34-0410-b5e6-96231b3b80d8

1 files changed, 3 insertions, 1 deletions

diff --git a/lib/CodeGen/LiveIntervalAnalysis.cpp b/lib/CodeGen/LiveIntervalAnalysis.cpp
index 8b25344b47..2558b09ad6 100644
--- a/lib/CodeGen/LiveIntervalAnalysis.cpp
+++ b/lib/CodeGen/LiveIntervalAnalysis.cpp
@@ -1562,7 +1562,9 @@ addIntervalsForSpills(const LiveInterval &li,
         if (!Folded) {
           LiveRange *LR = &nI.ranges[nI.ranges.size()-1];
           bool isKill = LR->end == getStoreIndex(index);
-          vrm.addSpillPoint(VReg, isKill, MI);
+          if (!MI->registerDefIsDead(nI.reg))
+            // No need to spill a dead def.
+            vrm.addSpillPoint(VReg, isKill, MI);
           if (isKill)
             AddedKill.insert(&nI);
         }