diff --git a/lib/Target/Hexagon/HexagonGenMux.cpp b/lib/Target/Hexagon/HexagonGenMux.cpp
index 3c37d9ebb0e..a2502ce5ec3 100644
--- a/lib/Target/Hexagon/HexagonGenMux.cpp
+++ b/lib/Target/Hexagon/HexagonGenMux.cpp
@@ -59,9 +59,7 @@ namespace {
   public:
     static char ID;
 
-    HexagonGenMux() : MachineFunctionPass(ID), HII(nullptr), HRI(nullptr) {
-      initializeHexagonGenMuxPass(*PassRegistry::getPassRegistry());
-    }
+    HexagonGenMux() : MachineFunctionPass(ID) {}
 
     StringRef getPassName() const override {
       return "Hexagon generate mux instructions";
@@ -79,8 +77,8 @@ namespace {
     }
 
   private:
-    const HexagonInstrInfo *HII;
-    const HexagonRegisterInfo *HRI;
+    const HexagonInstrInfo *HII = nullptr;
+    const HexagonRegisterInfo *HRI = nullptr;
 
     struct CondsetInfo {
       unsigned PredR = 0;
@@ -134,7 +132,7 @@ namespace {
 
 } // end anonymous namespace
 
-INITIALIZE_PASS(HexagonGenMux, "hexagon-mux",
+INITIALIZE_PASS(HexagonGenMux, "hexagon-gen-mux",
   "Hexagon generate mux instructions", false, false)
 
 void HexagonGenMux::getSubRegs(unsigned Reg, BitVector &SRs) const {
@@ -297,12 +295,15 @@ bool HexagonGenMux::genMuxInBlock(MachineBasicBlock &B) {
     unsigned SR1 = Src1->isReg() ? Src1->getReg() : 0;
     unsigned SR2 = Src2->isReg() ? Src2->getReg() : 0;
     bool Failure = false, CanUp = true, CanDown = true;
+    bool Used1 = false, Used2 = false;
     for (unsigned X = MinX+1; X < MaxX; X++) {
       const DefUseInfo &DU = DUM.lookup(X);
       if (DU.Defs[PR] || DU.Defs[DR] || DU.Uses[DR]) {
         Failure = true;
         break;
       }
+      Used1 |= DU.Uses[SR1];
+      Used2 |= DU.Uses[SR2];
       if (CanDown && DU.Defs[SR1])
         CanDown = false;
       if (CanUp && DU.Defs[SR2])
@@ -316,6 +317,15 @@ bool HexagonGenMux::genMuxInBlock(MachineBasicBlock &B) {
     // Prefer "down", since this will move the MUX farther away from the
     // predicate definition.
     MachineBasicBlock::iterator At = CanDown ? Def2 : Def1;
+    if (!CanDown) {
+      // If the MUX is placed "up", it shouldn't kill any source registers
+      // that are still used afterwards. We can reset the kill flags directly
+      // on the operands, because the source instructions will be erased.
+      if (Used1 && Src1->isReg())
+        Src1->setIsKill(false);
+      if (Used2 && Src2->isReg())
+        Src2->setIsKill(false);
+    }
     ML.push_back(MuxInfo(At, DR, PR, SrcT, SrcF, Def1, Def2));
   }
 
diff --git a/lib/Target/Hexagon/HexagonTargetMachine.cpp b/lib/Target/Hexagon/HexagonTargetMachine.cpp
index c757b6ecdd0..e507a797871 100644
--- a/lib/Target/Hexagon/HexagonTargetMachine.cpp
+++ b/lib/Target/Hexagon/HexagonTargetMachine.cpp
@@ -111,6 +111,7 @@ namespace llvm {
   extern char &HexagonExpandCondsetsID;
   void initializeHexagonExpandCondsetsPass(PassRegistry&);
   void initializeHexagonLoopIdiomRecognizePass(PassRegistry&);
+  void initializeHexagonGenMuxPass(PassRegistry&);
   void initializeHexagonOptAddrModePass(PassRegistry&);
   Pass *createHexagonLoopIdiomPass();
 
@@ -152,8 +153,11 @@ static Reloc::Model getEffectiveRelocModel(Optional<Reloc::Model> RM) {
 extern "C" void LLVMInitializeHexagonTarget() {
   // Register the target.
   RegisterTargetMachine<HexagonTargetMachine> X(getTheHexagonTarget());
-  initializeHexagonLoopIdiomRecognizePass(*PassRegistry::getPassRegistry());
-  initializeHexagonOptAddrModePass(*PassRegistry::getPassRegistry());
+
+  PassRegistry &PR = *PassRegistry::getPassRegistry();
+  initializeHexagonLoopIdiomRecognizePass(PR);
+  initializeHexagonGenMuxPass(PR);
+  initializeHexagonOptAddrModePass(PR);
 }
 
 HexagonTargetMachine::HexagonTargetMachine(const Target &T, const Triple &TT,
diff --git a/test/CodeGen/Hexagon/mux-kill.mir b/test/CodeGen/Hexagon/mux-kill.mir
new file mode 100644
index 00000000000..6944050e3da
--- /dev/null
+++ b/test/CodeGen/Hexagon/mux-kill.mir
@@ -0,0 +1,15 @@
+# RUN: llc -march=hexagon -run-pass hexagon-gen-mux -o - %s -verify-machineinstrs | FileCheck %s
+# CHECK: %r2 = C2_mux %p0, %r0, %r1
+---
+name: fred
+tracksRegLiveness: true
+
+body: |
+  bb.0:
+    liveins: %d0, %p0
+
+    %r2 = A2_tfrt %p0, %r0
+    %r0 = A2_tfr %r1
+    %r2 = A2_tfrf %p0, killed %r1
+...
+