Index: lib/CodeGen/LiveIntervalAnalysis.cpp
===================================================================
--- lib/CodeGen/LiveIntervalAnalysis.cpp
+++ lib/CodeGen/LiveIntervalAnalysis.cpp
@@ -982,10 +982,38 @@
       handleMoveDown(LR);
     else
       handleMoveUp(LR, Reg, LaneMask);
+
+    // Fix liveins to other blocks which may need to be changed to new liveouts.
+    updateSuccessors(LR, LIS.getSlotIndexes()->getMBBFromIndex(NewIdx));
+
     DEBUG(dbgs() << "        -->\t" << LR << '\n');
     LR.verify();
   }
 
+  // Update value numbers in successor blocks in case if we have a new liveout
+  // replacing an old one. I.e. if we have swapped two instructions defining
+  // subregisters of a same register. Last one becomes a new liveout.
+  // Only update Valno if supplied.
+  void updateSuccessors(LiveRange &LR, const MachineBasicBlock *MBB,
+                        VNInfo *Valno = nullptr) {
+    VNInfo *Out = LR.getVNInfoBefore(LIS.getMBBEndIdx(MBB));
+    if (!Out || (Valno && Out != Valno))
+      return;
+    // This is a liveout.
+    // Find live-ins to other blocks which should connect to this live-out.
+    for (const auto &Succ : MBB->successors()) {
+      // Now set new value number in a successor.
+      auto *InSeg = LR.getSegmentContaining(LIS.getMBBStartIdx(Succ));
+      if (InSeg && !InSeg->valno->isPHIDef() && InSeg->valno != Out) {
+        InSeg->valno = Out;
+        // Iterate next successors. No need to maintain visited list because
+        // when we update all possible segments loop will terminate.
+        if (InSeg->contains(LIS.getMBBEndIdx(Succ).getPrevSlot()))
+          updateSuccessors(LR, Succ, Out);
+      }
+    }
+  }
+
   /// Update LR to reflect an instruction has been moved downwards from OldIdx
   /// to NewIdx (OldIdx < NewIdx).
   void handleMoveDown(LiveRange &LR) {