diff --git a/llvm/include/llvm/CodeGen/TargetSubtargetInfo.h b/llvm/include/llvm/CodeGen/TargetSubtargetInfo.h
--- a/llvm/include/llvm/CodeGen/TargetSubtargetInfo.h
+++ b/llvm/include/llvm/CodeGen/TargetSubtargetInfo.h
@@ -297,6 +297,9 @@
   /// possible.
   virtual bool enableSubRegLiveness() const { return false; }
 
+  /// Enable coalescing of subregister.
+  virtual bool enableJoinSubRange() const { return false; }
+
   /// This is called after a .mir file was loaded.
   virtual void mirFileLoaded(MachineFunction &MF) const;
 
diff --git a/llvm/lib/CodeGen/RegisterCoalescer.cpp b/llvm/lib/CodeGen/RegisterCoalescer.cpp
--- a/llvm/lib/CodeGen/RegisterCoalescer.cpp
+++ b/llvm/lib/CodeGen/RegisterCoalescer.cpp
@@ -3346,10 +3346,11 @@
   LiveInterval &RHS = LIS->getInterval(CP.getSrcReg());
   LiveInterval &LHS = LIS->getInterval(CP.getDstReg());
   bool TrackSubRegLiveness = MRI->shouldTrackSubRegLiveness(*CP.getNewRC());
+  bool JoinSubRange = MF->getSubtarget().enableJoinSubRange();
   JoinVals RHSVals(RHS, CP.getSrcReg(), CP.getSrcIdx(), LaneBitmask::getNone(),
-                   NewVNInfo, CP, LIS, TRI, false, TrackSubRegLiveness);
+                   NewVNInfo, CP, LIS, TRI, JoinSubRange, TrackSubRegLiveness);
   JoinVals LHSVals(LHS, CP.getDstReg(), CP.getDstIdx(), LaneBitmask::getNone(),
-                   NewVNInfo, CP, LIS, TRI, false, TrackSubRegLiveness);
+                   NewVNInfo, CP, LIS, TRI, JoinSubRange, TrackSubRegLiveness);
 
   LLVM_DEBUG(dbgs() << "\t\tRHS = " << RHS << "\n\t\tLHS = " << LHS << '\n');