1 files changed, 11 insertions, 1 deletions
diff --git a/llvm/lib/CodeGen/LiveIntervals.cpp b/llvm/lib/CodeGen/LiveIntervals.cpp
index 0781a0b121b..2d5b8e79910 100644
--- a/llvm/lib/CodeGen/LiveIntervals.cpp
+++ b/llvm/lib/CodeGen/LiveIntervals.cpp
@@ -196,7 +196,11 @@ void LiveIntervals::computeVirtRegInterval(LiveInterval &LI) {
   assert(LI.empty() && "Should only compute empty intervals.");
   LRCalc->reset(MF, getSlotIndexes(), DomTree, &getVNInfoAllocator());
   LRCalc->calculate(LI, MRI->shouldTrackSubRegLiveness(LI.reg));
-  computeDeadValues(LI, nullptr);
+
+  if (computeDeadValues(LI, nullptr)) {
+    SmallVector<LiveInterval *, 4> SplitIntervals;
+    splitSeparateComponents(LI, SplitIntervals);
+  }
 }
 
 void LiveIntervals::computeVirtRegs() {
@@ -500,6 +504,8 @@ bool LiveIntervals::shrinkToUses(LiveInterval *li,
 bool LiveIntervals::computeDeadValues(LiveInterval &LI,
                                       SmallVectorImpl<MachineInstr*> *dead) {
   bool MayHaveSplitComponents = false;
+  bool HaveDeadDef = false;
+
   for (VNInfo *VNI : LI.valnos) {
     if (VNI->isUnused())
       continue;
@@ -530,6 +536,10 @@ bool LiveIntervals::computeDeadValues(LiveInterval &LI,
       MachineInstr *MI = getInstructionFromIndex(Def);
       assert(MI && "No instruction defining live value");
       MI->addRegisterDead(LI.reg, TRI);
+      if (HaveDeadDef)
+        MayHaveSplitComponents = true;
+      HaveDeadDef = true;
+
       if (dead && MI->allDefsAreDead()) {
         LLVM_DEBUG(dbgs() << "All defs dead: " << Def << '\t' << *MI);
         dead->push_back(MI);