diff --git a/lldb/packages/Python/lldbsuite/test/functionalities/param_entry_vals/basic_entry_values_x86_64/TestBasicEntryValuesX86_64.py b/lldb/packages/Python/lldbsuite/test/functionalities/param_entry_vals/basic_entry_values_x86_64/TestBasicEntryValuesX86_64.py
--- a/lldb/packages/Python/lldbsuite/test/functionalities/param_entry_vals/basic_entry_values_x86_64/TestBasicEntryValuesX86_64.py
+++ b/lldb/packages/Python/lldbsuite/test/functionalities/param_entry_vals/basic_entry_values_x86_64/TestBasicEntryValuesX86_64.py
@@ -6,8 +6,7 @@
 supported_platforms.extend(lldbplatformutil.getDarwinOSTriples())
 
 lldbinline.MakeInlineTest(__file__, globals(),
-        [decorators.skipIf(bugnumber="llvm.org/pr44059"),
-         decorators.skipUnlessPlatform(supported_platforms),
+        [decorators.skipUnlessPlatform(supported_platforms),
          decorators.skipIf(compiler="clang", compiler_version=['<', '10.0']),
          decorators.skipUnlessArch('x86_64'),
          decorators.skipUnlessHasCallSiteInfo,
diff --git a/lldb/packages/Python/lldbsuite/test/functionalities/param_entry_vals/basic_entry_values_x86_64/main.cpp b/lldb/packages/Python/lldbsuite/test/functionalities/param_entry_vals/basic_entry_values_x86_64/main.cpp
--- a/lldb/packages/Python/lldbsuite/test/functionalities/param_entry_vals/basic_entry_values_x86_64/main.cpp
+++ b/lldb/packages/Python/lldbsuite/test/functionalities/param_entry_vals/basic_entry_values_x86_64/main.cpp
@@ -18,6 +18,14 @@
       /* Clobbers */ : "rsi" \
   );
 
+// Destroy %rbx in the current frame.
+#define DESTROY_RBX \
+  asm volatile ("xorq %%rbx, %%rbx" \
+      /* Outputs */  : \
+      /* Inputs */   : \
+      /* Clobbers */ : "rbx" \
+  );
+
 struct S1 {
   int field1 = 123;
   int *field2 = &field1;
@@ -30,10 +38,17 @@
   // Destroy 'x' in the current frame.
   DESTROY_RSI;
 
-  //% self.filecheck("image lookup -va $pc", "main.cpp", "-check-prefix=FUNC1-DESC")
-  // FUNC1-DESC: name = "x", type = "int", location = DW_OP_entry_value(DW_OP_reg4 RSI)
+  // NOTE: Currently, we do not generate DW_OP_entry_value for the 'x',
+  // since it gets copied into a register that is not callee saved,
+  // and we can not guarantee that its value has not changed.
 
   ++sink;
+
+  // Destroy 'sink' in the current frame.
+  DESTROY_RBX;
+
+  //% self.filecheck("image lookup -va $pc", "main.cpp", "-check-prefix=FUNC1-DESC")
+  // FUNC1-DESC: name = "sink", type = "int &", location = DW_OP_entry_value(DW_OP_reg5 RDI)
 }
 
 __attribute__((noinline))
@@ -43,10 +58,16 @@
   // Destroy 'x' in the current frame.
   DESTROY_RSI;
 
-  //% self.filecheck("expr x", "main.cpp", "-check-prefix=FUNC2-EXPR")
-  // FUNC2-EXPR: (int) ${{.*}} = 123
+  //% self.filecheck("expr x", "main.cpp", "-check-prefix=FUNC2-EXPR-FAIL", expect_cmd_failure=True)
+  // FUNC2-EXPR-FAIL: couldn't get the value of variable x: variable not available
 
   ++sink;
+
+  // Destroy 'sink' in the current frame.
+  DESTROY_RBX;
+
+  //% self.filecheck("expr sink", "main.cpp", "-check-prefix=FUNC2-EXPR")
+  // FUNC2-EXPR: ${{.*}} = 2
 }
 
 __attribute__((noinline))
@@ -69,10 +90,16 @@
   // Destroy 'x' in the current frame.
   DESTROY_RSI;
 
-  //% self.filecheck("expr x", "main.cpp", "-check-prefix=FUNC4-EXPR", expect_cmd_failure=True)
-  // FUNC4-EXPR: couldn't get the value of variable x: Could not evaluate DW_OP_entry_value.
+  //% self.filecheck("expr x", "main.cpp", "-check-prefix=FUNC4-EXPR-FAIL", expect_cmd_failure=True)
+  // FUNC4-EXPR-FAIL: couldn't get the value of variable x: variable not available
 
   ++sink;
+
+  // Destroy 'sink' in the current frame.
+  DESTROY_RBX;
+
+  //% self.filecheck("expr sink", "main.cpp", "-check-prefix=FUNC4-EXPR", expect_cmd_failure=True)
+  // FUNC4-EXPR: couldn't get the value of variable sink: Could not evaluate DW_OP_entry_value.
 }
 
 __attribute__((noinline))
@@ -98,10 +125,16 @@
   // Destroy 'x' in the current frame.
   DESTROY_RSI;
 
-  //% self.filecheck("expr x", "main.cpp", "-check-prefix=FUNC7-EXPR")
-  // FUNC7-EXPR: (int) ${{.*}} = 123
+  //% self.filecheck("expr x", "main.cpp", "-check-prefix=FUNC7-EXPR-FAIL", expect_cmd_failure=True)
+  // FUNC7-EXPR-FAIL: couldn't get the value of variable x: variable not available
 
   ++sink;
+
+  // Destroy 'sink' in the current frame.
+  DESTROY_RBX;
+
+  //% self.filecheck("expr sink", "main.cpp", "-check-prefix=FUNC7-EXPR")
+  // FUNC7-EXPR: ${{.*}} = 4
 }
 
 __attribute__((always_inline))
@@ -129,10 +162,16 @@
   // Destroy 'x' in the current frame.
   DESTROY_RSI;
 
-  //% self.filecheck("expr x", "main.cpp", "-check-prefix=FUNC11-EXPR")
-  // FUNC11-EXPR: (int) ${{.*}} = 123
+  //% self.filecheck("expr x", "main.cpp", "-check-prefix=FUNC11-EXPR-FAIL", expect_cmd_failure=True)
+  // FUNC11-EXPR-FAIL: couldn't get the value of variable x: variable not available
 
   ++sink;
+
+  // Destroy 'sink' in the current frame.
+  DESTROY_RBX;
+
+  //% self.filecheck("expr sink", "main.cpp", "-check-prefix=FUNC11-EXPR")
+  // FUNC11-EXPR: ${{.*}} = 5
 }
 
 __attribute__((noinline))
@@ -150,10 +189,16 @@
   // Destroy 'x' in the current frame.
   DESTROY_RSI;
 
-  //% self.filecheck("expr x", "main.cpp", "-check-prefix=FUNC13-EXPR")
-  // FUNC13-EXPR: (int) ${{.*}} = 123
+  //% self.filecheck("expr x", "main.cpp", "-check-prefix=FUNC13-EXPR-FAIL", expect_cmd_failure=True)
+  // FUNC13-EXPR-FAIL: couldn't get the value of variable x: variable not available
 
-  ++sink;
+  use(sink);
+
+  // Destroy 'sink' in the current frame.
+  DESTROY_RBX;
+
+  //% self.filecheck("expr sink", "main.cpp", "-check-prefix=FUNC13-EXPR")
+  // FUNC13-EXPR: ${{.*}} = 5
 }
 
 __attribute__((noinline, disable_tail_calls))
diff --git a/llvm/lib/CodeGen/LiveDebugValues.cpp b/llvm/lib/CodeGen/LiveDebugValues.cpp
--- a/llvm/lib/CodeGen/LiveDebugValues.cpp
+++ b/llvm/lib/CodeGen/LiveDebugValues.cpp
@@ -226,7 +226,9 @@
       RegisterKind,
       SpillLocKind,
       ImmediateKind,
-      EntryValueKind
+      EntryValueKind,
+      EntryValueBackupKind,
+      EntryValueCopyBackupKind
     } Kind = InvalidKind;
 
     /// The value location. Stored separately to avoid repeatedly
@@ -248,7 +250,7 @@
       assert(MI.isDebugValue() && "not a DBG_VALUE");
       assert(MI.getNumOperands() == 4 && "malformed DBG_VALUE");
       if (int RegNo = isDbgValueDescribedByReg(MI)) {
-        Kind = MI.isDebugEntryValue() ? EntryValueKind : RegisterKind;
+        Kind = RegisterKind;
         Loc.RegNo = RegNo;
       } else if (MI.getOperand(0).isImm()) {
         Kind = ImmediateKind;
@@ -260,17 +262,50 @@
         Kind = ImmediateKind;
         Loc.CImm = MI.getOperand(0).getCImm();
       }
-      assert((Kind != ImmediateKind || !MI.isDebugEntryValue()) &&
-             "entry values must be register locations");
+
+      // We create the debug entry values from the factory functions rather than
+      // from this ctor.
+      assert(Kind != EntryValueKind && !isEntryBackupLoc());
     }
 
     /// Take the variable and machine-location in DBG_VALUE MI, and build an
     /// entry location using the given expression.
     static VarLoc CreateEntryLoc(const MachineInstr &MI, LexicalScopes &LS,
-                                 const DIExpression *EntryExpr) {
+                                 const DIExpression *EntryExpr, unsigned Reg) {
       VarLoc VL(MI, LS);
+      assert(VL.Kind == RegisterKind);
       VL.Kind = EntryValueKind;
       VL.Expr = EntryExpr;
+      VL.Loc.RegNo = Reg;
+      return VL;
+    }
+
+    /// Take the variable and machine-location from the DBG_VALUE (from the
+    /// function entry), and build an entry value backup location. The backup
+    /// location will turn into the normal location if the backup is valid at
+    /// the time of the primary location clobbering.
+    static VarLoc CreateEntryBackupLoc(const MachineInstr &MI,
+                                       LexicalScopes &LS,
+                                       const DIExpression *EntryExpr) {
+      VarLoc VL(MI, LS);
+      assert(VL.Kind == RegisterKind);
+      VL.Kind = EntryValueBackupKind;
+      VL.Expr = EntryExpr;
+      return VL;
+    }
+
+    /// Take the variable and machine-location from the DBG_VALUE (from the
+    /// function entry), and build a copy of an entry value backup location by
+    /// setting the register location to NewReg.
+    static VarLoc CreateEntryCopyBackupLoc(const MachineInstr &MI,
+                                           LexicalScopes &LS,
+                                           const DIExpression *EntryExpr,
+                                           unsigned NewReg) {
+      VarLoc VL(MI, LS);
+      assert(VL.Kind == RegisterKind);
+      VL.Kind = EntryValueCopyBackupKind;
+      VL.Expr = EntryExpr;
+      VL.Loc.RegNo = NewReg;
       return VL;
     }
 
@@ -309,8 +344,11 @@
       switch (Kind) {
       case EntryValueKind:
         // An entry value is a register location -- but with an updated
-        // expression.
-        return BuildMI(MF, DbgLoc, IID, Indirect, Loc.RegNo, Var, Expr);
+        // expression. The register location of such DBG_VALUE is always the one
+        // from the entry DBG_VALUE, it does not matter if the entry value was
+        // copied in to another register due to some optimizations.
+        return BuildMI(MF, DbgLoc, IID, Indirect, MI.getOperand(0).getReg(),
+                       Var, Expr);
       case RegisterKind:
         // Register locations are like the source DBG_VALUE, but with the
         // register number from this VarLoc.
@@ -329,8 +367,11 @@
         MachineOperand MO = MI.getOperand(0);
         return BuildMI(MF, DbgLoc, IID, Indirect, MO, Var, DIExpr);
       }
+      case EntryValueBackupKind:
+      case EntryValueCopyBackupKind:
       case InvalidKind:
-        llvm_unreachable("Tried to produce DBG_VALUE for invalid VarLoc");
+        llvm_unreachable(
+            "Tried to produce DBG_VALUE for invalid or backup VarLoc");
       }
       llvm_unreachable("Unrecognized LiveDebugValues.VarLoc.Kind enum");
     }
@@ -338,6 +379,27 @@
     /// Is the Loc field a constant or constant object?
     bool isConstant() const { return Kind == ImmediateKind; }
 
+    /// Check if the Loc field is an entry backup location.
+    bool isEntryBackupLoc() const {
+      return Kind == EntryValueBackupKind || Kind == EntryValueCopyBackupKind;
+    }
+
+    /// If this variable is described by a register holding the entry value,
+    /// return it, otherwise return 0.
+    unsigned getEntryValueBackupReg() const {
+      if (Kind == EntryValueBackupKind)
+        return Loc.RegNo;
+      return 0;
+    }
+
+    /// If this variable is described by a register holding the copy of the
+    /// entry value, return it, otherwise return 0.
+    unsigned getEntryValueCopyBackupReg() const {
+      if (Kind == EntryValueCopyBackupKind)
+        return Loc.RegNo;
+      return 0;
+    }
+
     /// If this variable is described by a register, return it,
     /// otherwise return 0.
     unsigned isDescribedByReg() const {
@@ -357,6 +419,8 @@
       switch (Kind) {
       case RegisterKind:
       case EntryValueKind:
+      case EntryValueBackupKind:
+      case EntryValueCopyBackupKind:
         dbgs() << printReg(Loc.RegNo, TRI);
         break;
       case SpillLocKind:
@@ -374,7 +438,12 @@
       if (Var.getInlinedAt())
         dbgs() << "!" << Var.getInlinedAt()->getMetadataID() << ")\n";
       else
-        dbgs() << "(null))\n";
+        dbgs() << "(null))";
+
+      if (isEntryBackupLoc())
+        dbgs() << " (backup loc)\n";
+      else
+        dbgs() << "\n";
     }
 #endif
 
@@ -390,7 +459,6 @@
     }
   };
 
-  using DebugParamMap = SmallDenseMap<const DILocalVariable *, MachineInstr *>;
   using VarLocMap = UniqueVector<VarLoc>;
   using VarLocSet = SparseBitVector<>;
   using VarLocInMBB = SmallDenseMap<const MachineBasicBlock *, VarLocSet>;
@@ -416,10 +484,18 @@
   /// This holds the working set of currently open ranges. For fast
   /// access, this is done both as a set of VarLocIDs, and a map of
   /// DebugVariable to recent VarLocID. Note that a DBG_VALUE ends all
-  /// previous open ranges for the same variable.
+  /// previous open ranges for the same variable. In addition, we keep
+  /// two different maps (Vars/EntryValuesBackupVars), so erase/insert
+  /// methods act differently depending on whether a VarLoc is primary
+  /// location or backup one. In the case the VarLoc is backup location
+  /// we will erase/insert from the EntryValuesBackupVars map, otherwise
+  /// we perform the operation on the Vars.
   class OpenRangesSet {
     VarLocSet VarLocs;
+    // Map the DebugVariable to recent primary location ID.
     SmallDenseMap<DebugVariable, unsigned, 8> Vars;
+    // Map the DebugVariable to recent backup location ID.
+    SmallDenseMap<DebugVariable, unsigned, 8> EntryValuesBackupVars;
     OverlapMap &OverlappingFragments;
 
   public:
@@ -427,40 +503,38 @@
 
     const VarLocSet &getVarLocs() const { return VarLocs; }
 
-    /// Terminate all open ranges for Var by removing it from the set.
-    void erase(DebugVariable Var);
+    /// Terminate all open ranges for VL.Var by removing it from the set.
+    void erase(const VarLoc &VL);
 
     /// Terminate all open ranges listed in \c KillSet by removing
     /// them from the set.
-    void erase(const VarLocSet &KillSet, const VarLocMap &VarLocIDs) {
-      VarLocs.intersectWithComplement(KillSet);
-      for (unsigned ID : KillSet)
-        Vars.erase(VarLocIDs[ID].Var);
-    }
+    void erase(const VarLocSet &KillSet, const VarLocMap &VarLocIDs);
 
     /// Insert a new range into the set.
-    void insert(unsigned VarLocID, DebugVariable Var) {
-      VarLocs.set(VarLocID);
-      Vars.insert({Var, VarLocID});
-    }
+    void insert(unsigned VarLocID, const VarLoc &VL);
 
     /// Insert a set of ranges.
     void insertFromLocSet(const VarLocSet &ToLoad, const VarLocMap &Map) {
       for (unsigned Id : ToLoad) {
-        const VarLoc &Var = Map[Id];
-        insert(Id, Var.Var);
+        const VarLoc &VarL = Map[Id];
+        insert(Id, VarL);
       }
     }
 
+    llvm::Optional<unsigned> getEntryValueBackup(DebugVariable Var);
+
     /// Empty the set.
     void clear() {
       VarLocs.clear();
       Vars.clear();
+      EntryValuesBackupVars.clear();
     }
 
     /// Return whether the set is empty or not.
     bool empty() const {
-      assert(Vars.empty() == VarLocs.empty() && "open ranges are inconsistent");
+      assert(Vars.empty() == EntryValuesBackupVars.empty() &&
+             Vars.empty() == VarLocs.empty() &&
+             "open ranges are inconsistent");
       return VarLocs.empty();
     }
   };
@@ -502,21 +576,23 @@
                           VarLocMap &VarLocIDs);
   void transferSpillOrRestoreInst(MachineInstr &MI, OpenRangesSet &OpenRanges,
                                   VarLocMap &VarLocIDs, TransferMap &Transfers);
+  bool removeEntryValue(const MachineInstr &MI, OpenRangesSet &OpenRanges,
+                        VarLocMap &VarLocIDs, const VarLoc &EntryVL);
   void emitEntryValues(MachineInstr &MI, OpenRangesSet &OpenRanges,
                        VarLocMap &VarLocIDs, TransferMap &Transfers,
-                       DebugParamMap &DebugEntryVals,
                        SparseBitVector<> &KillSet);
+  void recordEntryValue(const MachineInstr &MI,
+                        const DefinedRegsSet &DefinedRegs,
+                        OpenRangesSet &OpenRanges, VarLocMap &VarLocIDs);
   void transferRegisterCopy(MachineInstr &MI, OpenRangesSet &OpenRanges,
                             VarLocMap &VarLocIDs, TransferMap &Transfers);
   void transferRegisterDef(MachineInstr &MI, OpenRangesSet &OpenRanges,
-                           VarLocMap &VarLocIDs, TransferMap &Transfers,
-                           DebugParamMap &DebugEntryVals);
+                           VarLocMap &VarLocIDs, TransferMap &Transfers);
   bool transferTerminator(MachineBasicBlock *MBB, OpenRangesSet &OpenRanges,
                           VarLocInMBB &OutLocs, const VarLocMap &VarLocIDs);
 
   void process(MachineInstr &MI, OpenRangesSet &OpenRanges,
-               VarLocMap &VarLocIDs, TransferMap &Transfers,
-               DebugParamMap &DebugEntryVals);
+               VarLocMap &VarLocIDs, TransferMap &Transfers);
 
   void accumulateFragmentMap(MachineInstr &MI, VarToFragments &SeenFragments,
                              OverlapMap &OLapMap);
@@ -619,18 +695,24 @@
 }
 
 /// Erase a variable from the set of open ranges, and additionally erase any
-/// fragments that may overlap it.
-void LiveDebugValues::OpenRangesSet::erase(DebugVariable Var) {
+/// fragments that may overlap it. If the VarLoc is a buckup location, erase
+/// the variable from the EntryValuesBackupVars set, indicating we should stop
+/// tracking its backup entry location. Otherwise, if the VarLoc is primary
+/// location, erase the variable from the Vars set.
+void LiveDebugValues::OpenRangesSet::erase(const VarLoc &VL) {
   // Erasure helper.
-  auto DoErase = [this](DebugVariable VarToErase) {
-    auto It = Vars.find(VarToErase);
-    if (It != Vars.end()) {
+  auto DoErase = [VL, this](DebugVariable VarToErase) {
+    auto *EraseFrom = VL.isEntryBackupLoc() ? &EntryValuesBackupVars : &Vars;
+    auto It = EraseFrom->find(VarToErase);
+    if (It != EraseFrom->end()) {
       unsigned ID = It->second;
       VarLocs.reset(ID);
-      Vars.erase(It);
+      EraseFrom->erase(It);
     }
   };
 
+  DebugVariable Var = VL.Var;
+
   // Erase the variable/fragment that ends here.
   DoErase(Var);
 
@@ -651,6 +733,34 @@
   }
 }
 
+void LiveDebugValues::OpenRangesSet::erase(const VarLocSet &KillSet,
+                                           const VarLocMap &VarLocIDs) {
+  VarLocs.intersectWithComplement(KillSet);
+  for (unsigned ID : KillSet) {
+    const VarLoc *VL = &VarLocIDs[ID];
+    auto *EraseFrom = VL->isEntryBackupLoc() ? &EntryValuesBackupVars : &Vars;
+    EraseFrom->erase(VL->Var);
+  }
+}
+
+void LiveDebugValues::OpenRangesSet::insert(unsigned VarLocID,
+                                            const VarLoc &VL) {
+  auto *InsertInto = VL.isEntryBackupLoc() ? &EntryValuesBackupVars : &Vars;
+  VarLocs.set(VarLocID);
+  InsertInto->insert({VL.Var, VarLocID});
+}
+
+/// Return the Loc ID of an entry value backup location, if it exists for the
+/// variable.
+llvm::Optional<unsigned>
+LiveDebugValues::OpenRangesSet::getEntryValueBackup(DebugVariable Var) {
+  auto It = EntryValuesBackupVars.find(Var);
+  if (It != EntryValuesBackupVars.end())
+    return It->second;
+
+  return llvm::None;
+}
+
 //===----------------------------------------------------------------------===//
 //            Debug Range Extension Implementation
 //===----------------------------------------------------------------------===//
@@ -693,6 +803,62 @@
   return {Reg, Offset};
 }
 
+/// Try to salvage the debug entry value if we encounter a new debug value
+/// describing the same parameter, otherwise stop tracking the value. Return
+/// true if we should stop tracking the entry value, otherwise return false.
+bool LiveDebugValues::removeEntryValue(const MachineInstr &MI,
+                                       OpenRangesSet &OpenRanges,
+                                       VarLocMap &VarLocIDs,
+                                       const VarLoc &EntryVL) {
+  // Skip the DBG_VALUE which is the debug entry value itself.
+  if (MI.isIdenticalTo(EntryVL.MI))
+    return false;
+
+  // If the parameter's location is not register location, we can not track
+  // the entry value any more. In addition, if the debug expression from the
+  // DBG_VALUE is not empty, we can assume the parameter's value has changed
+  // indicating that we should stop tracking its entry value as well.
+  if (!MI.getOperand(0).isReg() ||
+      MI.getDebugExpression()->getNumElements() != 0)
+    return true;
+
+  // If the DBG_VALUE comes from a copy instruction that copies the entry value,
+  // it means the parameter's value has not changed and we should be able to use
+  // its entry value.
+  bool TrySalvageEntryValue = false;
+  Register Reg = MI.getOperand(0).getReg();
+  auto I = std::next(MI.getReverseIterator());
+  const MachineOperand *SrcRegOp, *DestRegOp;
+  if (I != MI.getParent()->rend()) {
+    // TODO: Try to keep tracking of an entry value if we encounter a propagated
+    // DBG_VALUE describing the copy of the entry value. (Propagated entry value
+    // does not indicate the parameter modification.)
+    auto DestSrc = TII->isCopyInstr(*I);
+    if (!DestSrc)
+      return true;
+
+    SrcRegOp = DestSrc->Source;
+    DestRegOp = DestSrc->Destination;
+    if (Reg != DestRegOp->getReg())
+      return true;
+    TrySalvageEntryValue = true;
+  }
+
+  if (TrySalvageEntryValue) {
+    for (unsigned ID : OpenRanges.getVarLocs()) {
+      const VarLoc &VL = VarLocIDs[ID];
+      if (!VL.isEntryBackupLoc())
+        continue;
+
+      if (VL.getEntryValueCopyBackupReg() == Reg &&
+          VL.MI.getOperand(0).getReg() == SrcRegOp->getReg())
+        return false;
+    }
+  }
+
+  return true;
+}
+
 /// End all previous ranges related to @MI and start a new range from @MI
 /// if it is a DBG_VALUE instr.
 void LiveDebugValues::transferDebugValue(const MachineInstr &MI,
@@ -707,18 +873,33 @@
   assert(Var->isValidLocationForIntrinsic(DebugLoc) &&
          "Expected inlined-at fields to agree");
 
-  // End all previous ranges of Var.
   DebugVariable V(Var, Expr, InlinedAt);
-  OpenRanges.erase(V);
 
-  // Add the VarLoc to OpenRanges from this DBG_VALUE.
+  // Check if this DBG_VALUE indicates a parameter's value changing.
+  // If that is the case, we should stop tracking its entry value.
+  auto EntryValBackupID = OpenRanges.getEntryValueBackup(V);
+  if (Var->isParameter() && EntryValBackupID) {
+    const VarLoc &EntryVL = VarLocIDs[*EntryValBackupID];
+    if (removeEntryValue(MI, OpenRanges, VarLocIDs, EntryVL)) {
+      LLVM_DEBUG(dbgs() << "Deleting a DBG entry value because of: ";
+                 MI.print(dbgs(), /*IsStandalone*/ false,
+                          /*SkipOpers*/ false, /*SkipDebugLoc*/ false,
+                          /*AddNewLine*/ true, TII));
+      OpenRanges.erase(EntryVL);
+    }
+  }
+
   unsigned ID;
   if (isDbgValueDescribedByReg(MI) || MI.getOperand(0).isImm() ||
       MI.getOperand(0).isFPImm() || MI.getOperand(0).isCImm()) {
     // Use normal VarLoc constructor for registers and immediates.
     VarLoc VL(MI, LS);
+    // End all previous ranges of VL.Var.
+    OpenRanges.erase(VL);
+
     ID = VarLocIDs.insert(VL);
-    OpenRanges.insert(ID, VL.Var);
+    // Add the VarLoc to OpenRanges from this DBG_VALUE.
+    OpenRanges.insert(ID, VL);
   } else if (MI.hasOneMemOperand()) {
     llvm_unreachable("DBG_VALUE with mem operand encountered after regalloc?");
   } else {
@@ -728,32 +909,30 @@
   }
 }
 
+/// Turn the entry value backup locations into primary locations.
 void LiveDebugValues::emitEntryValues(MachineInstr &MI,
                                       OpenRangesSet &OpenRanges,
                                       VarLocMap &VarLocIDs,
                                       TransferMap &Transfers,
-                                      DebugParamMap &DebugEntryVals,
                                       SparseBitVector<> &KillSet) {
   for (unsigned ID : KillSet) {
     if (!VarLocIDs[ID].Var.getVar()->isParameter())
       continue;
 
-    const MachineInstr *CurrDebugInstr = &VarLocIDs[ID].MI;
+    auto DebugVar = VarLocIDs[ID].Var;
+    auto EntryValBackupID = OpenRanges.getEntryValueBackup(DebugVar);
 
-    // If parameter's DBG_VALUE is not in the map that means we can't
-    // generate parameter's entry value.
-    if (!DebugEntryVals.count(CurrDebugInstr->getDebugVariable()))
+    // If the parameter has the entry value backup, it means we should
+    // be able to use its entry value.
+    if (!EntryValBackupID)
       continue;
 
-    auto ParamDebugInstr = DebugEntryVals[CurrDebugInstr->getDebugVariable()];
-    DIExpression *NewExpr = DIExpression::prepend(
-        ParamDebugInstr->getDebugExpression(), DIExpression::EntryValue);
-
-    VarLoc EntryLoc = VarLoc::CreateEntryLoc(*ParamDebugInstr, LS, NewExpr);
-
-    unsigned EntryValLocID = VarLocIDs.insert(EntryLoc);
-    Transfers.push_back({&MI, EntryValLocID});
-    OpenRanges.insert(EntryValLocID, EntryLoc.Var);
+    const VarLoc &EntryVL = VarLocIDs[*EntryValBackupID];
+    VarLoc EntryLoc =
+        VarLoc::CreateEntryLoc(EntryVL.MI, LS, EntryVL.Expr, EntryVL.Loc.RegNo);
+    unsigned EntryValueID = VarLocIDs.insert(EntryLoc);
+    Transfers.push_back({&MI, EntryValueID});
+    OpenRanges.insert(EntryValueID, EntryLoc);
   }
 }
 
@@ -774,17 +953,17 @@
 
     // Close this variable's previous location range.
     DebugVariable V(*DebugInstr);
-    OpenRanges.erase(V);
+    OpenRanges.erase(VL);
 
     // Record the new location as an open range, and a postponed transfer
     // inserting a DBG_VALUE for this location.
-    OpenRanges.insert(LocId, VL.Var);
+    OpenRanges.insert(LocId, VL);
     TransferDebugPair MIP = {&MI, LocId};
     Transfers.push_back(MIP);
   };
 
-  // End all previous ranges of Var.
-  OpenRanges.erase(VarLocIDs[OldVarID].Var);
+  // End all previous ranges of VL.Var.
+  OpenRanges.erase(VarLocIDs[OldVarID]);
   switch (Kind) {
   case TransferKind::TransferCopy: {
     assert(NewReg &&
@@ -832,7 +1011,7 @@
 /// A definition of a register may mark the end of a range.
 void LiveDebugValues::transferRegisterDef(
     MachineInstr &MI, OpenRangesSet &OpenRanges, VarLocMap &VarLocIDs,
-    TransferMap &Transfers, DebugParamMap &DebugEntryVals) {
+    TransferMap &Transfers) {
   MachineFunction *MF = MI.getMF();
   const TargetLowering *TLI = MF->getSubtarget().getTargetLowering();
   unsigned SP = TLI->getStackPointerRegisterToSaveRestore();
@@ -866,8 +1045,7 @@
   if (auto *TPC = getAnalysisIfAvailable<TargetPassConfig>()) {
     auto &TM = TPC->getTM<TargetMachine>();
     if (TM.Options.EnableDebugEntryValues)
-      emitEntryValues(MI, OpenRanges, VarLocIDs, Transfers, DebugEntryVals,
-                      KillSet);
+      emitEntryValues(MI, OpenRanges, VarLocIDs, Transfers, KillSet);
   }
 }
 
@@ -1026,14 +1204,14 @@
                                            OpenRangesSet &OpenRanges,
                                            VarLocMap &VarLocIDs,
                                            TransferMap &Transfers) {
-
   auto DestSrc = TII->isCopyInstr(MI);
   if (!DestSrc)
     return;
 
   const MachineOperand *DestRegOp = DestSrc->Destination;
   const MachineOperand *SrcRegOp = DestSrc->Source;
-  if (!SrcRegOp->isKill() || !DestRegOp->isDef())
+
+  if (!DestRegOp->isDef())
     return;
 
   auto isCalleeSavedReg = [&](unsigned Reg) {
@@ -1054,6 +1232,30 @@
   if (!isCalleeSavedReg(DestReg))
     return;
 
+  // Remember an entry value movement. If we encounter a new debug value of
+  // a parameter describing only a moving of the value around, rather then
+  // modifying it, we are still able to use the entry value if needed.
+  if (isRegOtherThanSPAndFP(*DestRegOp, MI, TRI)) {
+    for (unsigned ID : OpenRanges.getVarLocs()) {
+      if (VarLocIDs[ID].getEntryValueBackupReg() == SrcReg) {
+        LLVM_DEBUG(dbgs() << "Copy of the entry value: "; MI.dump(););
+        VarLoc EntryValLocCopyBackup = VarLoc::CreateEntryCopyBackupLoc(
+            VarLocIDs[ID].MI, LS, VarLocIDs[ID].Expr, DestReg);
+
+        // Stop tracking the original entry value.
+        OpenRanges.erase(VarLocIDs[ID]);
+
+        // Start tracking the entry value copy.
+        unsigned EntryValCopyLocID = VarLocIDs.insert(EntryValLocCopyBackup);
+        OpenRanges.insert(EntryValCopyLocID, EntryValLocCopyBackup);
+        break;
+      }
+    }
+  }
+
+  if (!SrcRegOp->isKill())
+    return;
+
   for (unsigned ID : OpenRanges.getVarLocs()) {
     if (VarLocIDs[ID].isDescribedByReg() == SrcReg) {
       insertTransferDebugPair(MI, OpenRanges, Transfers, VarLocIDs, ID,
@@ -1148,11 +1350,9 @@
 
 /// This routine creates OpenRanges.
 void LiveDebugValues::process(MachineInstr &MI, OpenRangesSet &OpenRanges,
-                              VarLocMap &VarLocIDs, TransferMap &Transfers,
-                              DebugParamMap &DebugEntryVals) {
+                              VarLocMap &VarLocIDs, TransferMap &Transfers) {
   transferDebugValue(MI, OpenRanges, VarLocIDs);
-  transferRegisterDef(MI, OpenRanges, VarLocIDs, Transfers,
-                      DebugEntryVals);
+  transferRegisterDef(MI, OpenRanges, VarLocIDs, Transfers);
   transferRegisterCopy(MI, OpenRanges, VarLocIDs, Transfers);
   transferSpillOrRestoreInst(MI, OpenRanges, VarLocIDs, Transfers);
 }
@@ -1273,6 +1473,8 @@
       // The ID location is live-in to MBB -- work out what kind of machine
       // location it is and create a DBG_VALUE.
       const VarLoc &DiffIt = VarLocIDs[ID];
+      if (DiffIt.isEntryBackupLoc())
+        continue;
       MachineInstr *MI = DiffIt.BuildDbgValue(*MBB.getParent());
       MBB.insert(MBB.instr_begin(), MI);
 
@@ -1284,8 +1486,7 @@
 
 bool LiveDebugValues::isEntryValueCandidate(
     const MachineInstr &MI, const DefinedRegsSet &DefinedRegs) const {
-  if (!MI.isDebugValue())
-    return false;
+  assert(MI.isDebugValue() && "This must be DBG_VALUE.");
 
   // TODO: Add support for local variables that are expressed in terms of
   // parameters entry values.
@@ -1332,6 +1533,34 @@
         Regs.insert(*AI);
 }
 
+/// This routine records the entry values of function parameters. The values
+/// could be used as backup values. If we loose the track of some unmodified
+/// parameters, the backup values will be used as a primary locations.
+void LiveDebugValues::recordEntryValue(const MachineInstr &MI,
+                                       const DefinedRegsSet &DefinedRegs,
+                                       OpenRangesSet &OpenRanges,
+                                       VarLocMap &VarLocIDs) {
+  if (auto *TPC = getAnalysisIfAvailable<TargetPassConfig>()) {
+    auto &TM = TPC->getTM<TargetMachine>();
+    if (!TM.Options.EnableDebugEntryValues)
+      return;
+  }
+
+  if (!isEntryValueCandidate(MI, DefinedRegs) ||
+      OpenRanges.getEntryValueBackup(DebugVariable(MI)))
+    return;
+
+  LLVM_DEBUG(dbgs() << "Creating the backup entry location: "; MI.dump(););
+
+  // Create the entry value and use it as a backup location until it is
+  // valid. It is valid until a parameter is not changed.
+  DIExpression *NewExpr =
+      DIExpression::prepend(MI.getDebugExpression(), DIExpression::EntryValue);
+  VarLoc EntryValLocAsBackup = VarLoc::CreateEntryBackupLoc(MI, LS, NewExpr);
+  unsigned EntryValLocID = VarLocIDs.insert(EntryValLocAsBackup);
+  OpenRanges.insert(EntryValLocID, EntryValLocAsBackup);
+}
+
 /// Calculate the liveness information for the given machine function and
 /// extend ranges across basic blocks.
 bool LiveDebugValues::ExtendRanges(MachineFunction &MF) {
@@ -1368,23 +1597,17 @@
                       std::greater<unsigned int>>
       Pending;
 
-  // Working set of currently collected debug variables mapped to DBG_VALUEs
-  // representing candidates for production of debug entry values.
-  DebugParamMap DebugEntryVals;
-
   // Set of register defines that are seen when traversing the entry block
   // looking for debug entry value candidates.
   DefinedRegsSet DefinedRegs;
 
   // Only in the case of entry MBB collect DBG_VALUEs representing
   // function parameters in order to generate debug entry values for them.
-
   MachineBasicBlock &First_MBB = *(MF.begin());
   for (auto &MI : First_MBB) {
     collectRegDefs(MI, DefinedRegs, TRI);
-    if (isEntryValueCandidate(MI, DefinedRegs) &&
-        !DebugEntryVals.count(MI.getDebugVariable()))
-      DebugEntryVals[MI.getDebugVariable()] = &MI;
+      if (MI.isDebugValue())
+        recordEntryValue(MI, DefinedRegs, OpenRanges, VarLocIDs);
   }
 
   // Initialize per-block structures and scan for fragment overlaps.
@@ -1443,7 +1666,7 @@
         // First load any pending inlocs.
         OpenRanges.insertFromLocSet(PendingInLocs[MBB], VarLocIDs);
         for (auto &MI : *MBB)
-          process(MI, OpenRanges, VarLocIDs, Transfers, DebugEntryVals);
+          process(MI, OpenRanges, VarLocIDs, Transfers);
         OLChanged |= transferTerminator(MBB, OpenRanges, OutLocs, VarLocIDs);
 
         LLVM_DEBUG(printVarLocInMBB(MF, OutLocs, VarLocIDs,
diff --git a/llvm/test/DebugInfo/MIR/ARM/dbgcall-site-propagated-value.mir b/llvm/test/DebugInfo/MIR/ARM/dbgcall-site-propagated-value.mir
--- a/llvm/test/DebugInfo/MIR/ARM/dbgcall-site-propagated-value.mir
+++ b/llvm/test/DebugInfo/MIR/ARM/dbgcall-site-propagated-value.mir
@@ -129,6 +129,19 @@
 ---
 name:            callee
 tracksRegLiveness: true
+stack:
+  - { id: 0, name: '', type: spill-slot, offset: -4, size: 4, alignment: 4,
+      stack-id: default, callee-saved-register: '$lr', callee-saved-restored: true,
+      debug-info-variable: '', debug-info-expression: '', debug-info-location: '' }
+  - { id: 1, name: '', type: spill-slot, offset: -8, size: 4, alignment: 4,
+      stack-id: default, callee-saved-register: '$r11', callee-saved-restored: true,
+      debug-info-variable: '', debug-info-expression: '', debug-info-location: '' }
+  - { id: 2, name: '', type: spill-slot, offset: -12, size: 4, alignment: 4,
+      stack-id: default, callee-saved-register: '$r10', callee-saved-restored: true,
+      debug-info-variable: '', debug-info-expression: '', debug-info-location: '' }
+  - { id: 3, name: '', type: spill-slot, offset: -16, size: 4, alignment: 4,
+      stack-id: default, callee-saved-register: '$r4', callee-saved-restored: true,
+      debug-info-variable: '', debug-info-expression: '', debug-info-location: '' }
 body:             |
   bb.0:
     successors: %bb.2(0x30000000), %bb.1(0x50000000)
diff --git a/llvm/test/DebugInfo/MIR/X86/entry-value-of-modified-param.mir b/llvm/test/DebugInfo/MIR/X86/entry-value-of-modified-param.mir
new file mode 100644
--- /dev/null
+++ b/llvm/test/DebugInfo/MIR/X86/entry-value-of-modified-param.mir
@@ -0,0 +1,121 @@
+# RUN: llc -debug-entry-values -run-pass=livedebugvalues -march=x86-64 -o - %s | FileCheck %s
+#
+#extern void fn1 (int, int, int);
+#
+#__attribute__((noinline))
+#int
+#fn2 (int a, int b, int c) {
+#  int q = 2 + a;
+#
+#  fn1 (5, 6, q);
+#
+#  b = b + 7;
+#  if (b < 17)
+#    return 1;
+#  else
+#    return 0;
+#}
+#
+# CHECK: ![[ARG_A:.*]] = !DILocalVariable(name: "a"
+# CHECK: ![[ARG_B:.*]] = !DILocalVariable(name: "b"
+# CHECK: ![[ARG_C:.*]] = !DILocalVariable(name: "c"
+# CHECK: DBG_VALUE $edi, $noreg, ![[ARG_A]], !DIExpression(DW_OP_LLVM_entry_value, 1)
+# CHECK: DBG_VALUE $edx, $noreg, ![[ARG_C]], !DIExpression(DW_OP_LLVM_entry_value, 1)
+# CHECK: DBG_VALUE $edi, $noreg, ![[ARG_A]], !DIExpression(DW_OP_LLVM_entry_value, 1)
+# CHECK-NOT: DBG_VALUE $esi, $noreg, ![[ARG_B]], !DIExpression(DW_OP_LLVM_entry_value, 1)
+#
+--- |
+  ; ModuleID = 'test.c'
+  source_filename = "test.c"
+  target datalayout = "e-m:e-p270:32:32-p271:32:32-p272:64:64-i64:64-f80:128-n8:16:32:64-S128"
+  target triple = "x86_64-unknown-linux-gnu"
+
+  ; Function Attrs: noinline nounwind uwtable
+  define dso_local i32 @fn2(i32 %a, i32 %b, i32 %c) local_unnamed_addr !dbg !12 {
+  entry:
+    call void @llvm.dbg.value(metadata i32 %a, metadata !16, metadata !DIExpression()), !dbg !20
+    call void @llvm.dbg.value(metadata i32 %b, metadata !17, metadata !DIExpression()), !dbg !20
+    call void @llvm.dbg.value(metadata i32 %c, metadata !18, metadata !DIExpression()), !dbg !20
+    %add = add nsw i32 %a, 2, !dbg !21
+    call void @llvm.dbg.value(metadata i32 %add, metadata !19, metadata !DIExpression()), !dbg !20
+    tail call void @fn1(i32 5, i32 6, i32 %add), !dbg !22
+    call void @llvm.dbg.value(metadata i32 %b, metadata !17, metadata !DIExpression(DW_OP_plus_uconst, 7, DW_OP_stack_value)), !dbg !20
+    %cmp = icmp slt i32 %b, 10, !dbg !23
+    %. = zext i1 %cmp to i32, !dbg !25
+    ret i32 %., !dbg !26
+  }
+
+  declare !dbg !4 dso_local void @fn1(i32, i32, i32) local_unnamed_addr
+
+  ; Function Attrs: nounwind readnone speculatable willreturn
+  declare void @llvm.dbg.value(metadata, metadata, metadata)
+
+  !llvm.dbg.cu = !{!0}
+  !llvm.module.flags = !{!8, !9, !10}
+  !llvm.ident = !{!11}
+
+  !0 = distinct !DICompileUnit(language: DW_LANG_C99, file: !1, producer: "clang version 10.0.0", isOptimized: true, runtimeVersion: 0, emissionKind: FullDebug, enums: !2, retainedTypes: !3, nameTableKind: None)
+  !1 = !DIFile(filename: "test.c", directory: "/dir")
+  !2 = !{}
+  !3 = !{!4}
+  !4 = !DISubprogram(name: "fn1", scope: !1, file: !1, line: 1, type: !5, flags: DIFlagPrototyped, spFlags: DISPFlagOptimized, retainedNodes: !2)
+  !5 = !DISubroutineType(types: !6)
+  !6 = !{null, !7, !7, !7}
+  !7 = !DIBasicType(name: "int", size: 32, encoding: DW_ATE_signed)
+  !8 = !{i32 2, !"Dwarf Version", i32 4}
+  !9 = !{i32 2, !"Debug Info Version", i32 3}
+  !10 = !{i32 1, !"wchar_size", i32 4}
+  !11 = !{!"clang version 10.0.0"}
+  !12 = distinct !DISubprogram(name: "fn2", scope: !1, file: !1, line: 5, type: !13, scopeLine: 6, flags: DIFlagPrototyped | DIFlagAllCallsDescribed, spFlags: DISPFlagDefinition | DISPFlagOptimized, unit: !0, retainedNodes: !15)
+  !13 = !DISubroutineType(types: !14)
+  !14 = !{!7, !7, !7, !7}
+  !15 = !{!16, !17, !18, !19}
+  !16 = !DILocalVariable(name: "a", arg: 1, scope: !12, file: !1, line: 5, type: !7)
+  !17 = !DILocalVariable(name: "b", arg: 2, scope: !12, file: !1, line: 5, type: !7)
+  !18 = !DILocalVariable(name: "c", arg: 3, scope: !12, file: !1, line: 5, type: !7)
+  !19 = !DILocalVariable(name: "q", scope: !12, file: !1, line: 7, type: !7)
+  !20 = !DILocation(line: 0, scope: !12)
+  !21 = !DILocation(line: 7, column: 15, scope: !12)
+  !22 = !DILocation(line: 9, column: 5, scope: !12)
+  !23 = !DILocation(line: 12, column: 11, scope: !24)
+  !24 = distinct !DILexicalBlock(scope: !12, file: !1, line: 12, column: 9)
+  !25 = !DILocation(line: 0, scope: !24)
+  !26 = !DILocation(line: 16, column: 1, scope: !12)
+
+...
+---
+name:            fn2
+alignment:       16
+callSites:
+  - { bb: 0, offset: 14, fwdArgRegs:
+      - { arg: 0, reg: '$edi' }
+      - { arg: 1, reg: '$esi' }
+      - { arg: 2, reg: '$edx' } }
+body:             |
+  bb.0.entry:
+    liveins: $edi, $esi, $rbx
+
+    DBG_VALUE $edi, $noreg, !16, !DIExpression(), debug-location !20
+    DBG_VALUE $esi, $noreg, !17, !DIExpression(), debug-location !20
+    DBG_VALUE $edx, $noreg, !18, !DIExpression(), debug-location !20
+    frame-setup PUSH64r killed $rbx, implicit-def $rsp, implicit $rsp
+    CFI_INSTRUCTION def_cfa_offset 16
+    CFI_INSTRUCTION offset $rbx, -16
+    $ebx = MOV32rr $esi
+    DBG_VALUE $ebx, $noreg, !17, !DIExpression(), debug-location !20
+    renamable $edi = KILL $edi, implicit-def $rdi
+    DBG_VALUE $edi, $noreg, !16, !DIExpression(), debug-location !20
+    renamable $edx = LEA64_32r killed renamable $rdi, 1, $noreg, 2, $noreg, debug-location !21
+    DBG_VALUE $edx, $noreg, !19, !DIExpression(), debug-location !20
+    $edi = MOV32ri 5, debug-location !22
+    $esi = MOV32ri 6, debug-location !22
+    CALL64pcrel32 @fn1, csr_64, implicit $rsp, implicit $ssp, implicit $edi, implicit $esi, implicit $edx, implicit-def $rsp, implicit-def $ssp, debug-location !22
+    DBG_VALUE $ebx, $noreg, !17, !DIExpression(DW_OP_plus_uconst, 7, DW_OP_stack_value), debug-location !20
+    renamable $eax = XOR32rr undef $eax, undef $eax, implicit-def dead $eflags, debug-location !23
+    CMP32ri8 killed renamable $ebx, 10, implicit-def $eflags, debug-location !23
+    renamable $al = SETCCr 12, implicit killed $eflags, implicit killed $eax, implicit-def $eax, debug-location !23
+    $rbx = frame-destroy POP64r implicit-def $rsp, implicit $rsp, debug-location !26
+    CFI_INSTRUCTION def_cfa_offset 8, debug-location !26
+    RETQ $eax, debug-location !26
+
+...
diff --git a/llvm/test/DebugInfo/MIR/X86/entry-values-diamond-bbs.mir b/llvm/test/DebugInfo/MIR/X86/entry-values-diamond-bbs.mir
new file mode 100644
--- /dev/null
+++ b/llvm/test/DebugInfo/MIR/X86/entry-values-diamond-bbs.mir
@@ -0,0 +1,179 @@
+# RUN: llc -debug-entry-values -run-pass=livedebugvalues -march=x86-64 -o - %s | FileCheck %s
+#
+# The test case was artificially adjusted, in order to make proper diamond basic
+# block structure relevant to the debug entry values propagation.
+#
+# CHECK: ![[ARG_B:.*]] = !DILocalVariable(name: "b"
+# CHECK: bb.0.entry
+# CHECK: DBG_VALUE $esi, $noreg, ![[ARG_B]], !DIExpression()
+# CHECK: bb.1.if.then
+# CHECK: DBG_VALUE $esi, $noreg, ![[ARG_B]], !DIExpression()
+# CHECK: $ebx = MOV32rr $esi
+# CHECK-NEXT: DBG_VALUE $ebx, $noreg, ![[ARG_B]], !DIExpression()
+# CHECK-NEXT: $esi = MOV32ri 5
+# CHECK-NEXT: $ebx = MOV32ri 1
+# CHECK-NEXT: DBG_VALUE $esi, $noreg, ![[ARG_B]], !DIExpression(DW_OP_LLVM_entry_value, 1)
+# CHECK: bb.2.if.else
+# CHECK: DBG_VALUE $esi, $noreg, ![[ARG_B]], !DIExpression()
+# CHECK: $ebx = MOV32rr $esi
+# CHECK-NEXT: DBG_VALUE $ebx, $noreg, ![[ARG_B]], !DIExpression()
+# CHECK-NEXT: $esi = MOV32ri 1
+# CHECK-NEXT: $ebx = MOV32ri 2
+# CHECK-NEXT: DBG_VALUE $esi, $noreg, ![[ARG_B]], !DIExpression(DW_OP_LLVM_entry_value, 1)
+# CHECK: bb.3.if.end
+# CHECK-NEXT: DBG_VALUE $esi, $noreg, ![[ARG_B]], !DIExpression(DW_OP_LLVM_entry_value, 1)
+#
+--- |
+  ; ModuleID = 'test.c'
+  source_filename = "test.c"
+  target datalayout = "e-m:e-p270:32:32-p271:32:32-p272:64:64-i64:64-f80:128-n8:16:32:64-S128"
+  target triple = "x86_64-unknown-linux-gnu"
+
+  ; Function Attrs: noinline nounwind uwtable
+  define dso_local i32 @fn2(i32 %a, i32 %b, i32 %c) local_unnamed_addr !dbg !12 {
+  entry:
+    call void @llvm.dbg.value(metadata i32 %a, metadata !16, metadata !DIExpression()), !dbg !20
+    call void @llvm.dbg.value(metadata i32 %b, metadata !17, metadata !DIExpression()), !dbg !20
+    call void @llvm.dbg.value(metadata i32 %c, metadata !18, metadata !DIExpression()), !dbg !20
+    %add = add nsw i32 %a, 2, !dbg !21
+    call void @llvm.dbg.value(metadata i32 %add, metadata !19, metadata !DIExpression()), !dbg !20
+    tail call void @fn1(i32 5, i32 6, i32 %add) #3, !dbg !22
+    %cmp = icmp slt i32 %b, 17, !dbg !23
+    br i1 %cmp, label %if.then, label %if.else, !dbg !25
+
+  if.then:                                          ; preds = %entry
+    %add1 = add nsw i32 %b, 7, !dbg !26
+    call void @llvm.dbg.value(metadata i32 %add1, metadata !17, metadata !DIExpression()), !dbg !20
+    tail call void @fn1(i32 5, i32 %add1, i32 %c) #3, !dbg !28
+    br label %if.end, !dbg !29
+
+  if.else:                                          ; preds = %entry
+    %add2 = add nuw nsw i32 %b, 1, !dbg !30
+    call void @llvm.dbg.value(metadata i32 %add2, metadata !17, metadata !DIExpression()), !dbg !20
+    tail call void @fn1(i32 1, i32 %add2, i32 %c) #3, !dbg !32
+    br label %if.end
+
+  if.end:                                           ; preds = %if.else, %if.then
+    %b.addr.0 = phi i32 [ %add1, %if.then ], [ %add2, %if.else ], !dbg !33
+    call void @llvm.dbg.value(metadata i32 %b.addr.0, metadata !17, metadata !DIExpression()), !dbg !20
+    ret i32 %b.addr.0, !dbg !34
+  }
+
+  declare !dbg !4 dso_local void @fn1(i32, i32, i32) local_unnamed_addr
+
+  ; Function Attrs: nounwind readnone speculatable willreturn
+  declare void @llvm.dbg.value(metadata, metadata, metadata)
+
+  !llvm.dbg.cu = !{!0}
+  !llvm.module.flags = !{!8, !9, !10}
+  !llvm.ident = !{!11}
+
+  !0 = distinct !DICompileUnit(language: DW_LANG_C99, file: !1, producer: "clang version 10.0.0", isOptimized: true, runtimeVersion: 0, emissionKind: FullDebug, enums: !2, retainedTypes: !3, nameTableKind: None)
+  !1 = !DIFile(filename: "test.c", directory: "/dir")
+  !2 = !{}
+  !3 = !{!4}
+  !4 = !DISubprogram(name: "fn1", scope: !1, file: !1, line: 1, type: !5, flags: DIFlagPrototyped, spFlags: DISPFlagOptimized, retainedNodes: !2)
+  !5 = !DISubroutineType(types: !6)
+  !6 = !{null, !7, !7, !7}
+  !7 = !DIBasicType(name: "int", size: 32, encoding: DW_ATE_signed)
+  !8 = !{i32 2, !"Dwarf Version", i32 4}
+  !9 = !{i32 2, !"Debug Info Version", i32 3}
+  !10 = !{i32 1, !"wchar_size", i32 4}
+  !11 = !{!"clang version 10.0.0"}
+  !12 = distinct !DISubprogram(name: "fn2", scope: !1, file: !1, line: 5, type: !13, scopeLine: 6, flags: DIFlagPrototyped | DIFlagAllCallsDescribed, spFlags: DISPFlagDefinition | DISPFlagOptimized, unit: !0, retainedNodes: !15)
+  !13 = !DISubroutineType(types: !14)
+  !14 = !{!7, !7, !7, !7}
+  !15 = !{!16, !17, !18, !19}
+  !16 = !DILocalVariable(name: "a", arg: 1, scope: !12, file: !1, line: 5, type: !7)
+  !17 = !DILocalVariable(name: "b", arg: 2, scope: !12, file: !1, line: 5, type: !7)
+  !18 = !DILocalVariable(name: "c", arg: 3, scope: !12, file: !1, line: 5, type: !7)
+  !19 = !DILocalVariable(name: "q", scope: !12, file: !1, line: 7, type: !7)
+  !20 = !DILocation(line: 0, scope: !12)
+  !21 = !DILocation(line: 7, column: 15, scope: !12)
+  !22 = !DILocation(line: 9, column: 5, scope: !12)
+  !23 = !DILocation(line: 11, column: 11, scope: !24)
+  !24 = distinct !DILexicalBlock(scope: !12, file: !1, line: 11, column: 9)
+  !25 = !DILocation(line: 11, column: 9, scope: !12)
+  !26 = !DILocation(line: 12, column: 13, scope: !27)
+  !27 = distinct !DILexicalBlock(scope: !24, file: !1, line: 11, column: 17)
+  !28 = !DILocation(line: 13, column: 8, scope: !27)
+  !29 = !DILocation(line: 14, column: 5, scope: !27)
+  !30 = !DILocation(line: 15, column: 13, scope: !31)
+  !31 = distinct !DILexicalBlock(scope: !24, file: !1, line: 14, column: 12)
+  !32 = !DILocation(line: 16, column: 7, scope: !31)
+  !33 = !DILocation(line: 0, scope: !24)
+  !34 = !DILocation(line: 19, column: 5, scope: !12)
+
+...
+---
+name:            fn2
+alignment:       16
+fixedStack:
+  - { id: 0, type: spill-slot, offset: -24, size: 8, alignment: 8, stack-id: default,
+      callee-saved-register: '$rbx', callee-saved-restored: true, debug-info-variable: '',
+      debug-info-expression: '', debug-info-location: '' }
+  - { id: 1, type: spill-slot, offset: -16, size: 8, alignment: 16, stack-id: default,
+      callee-saved-register: '$rbp', callee-saved-restored: true, debug-info-variable: '',
+      debug-info-expression: '', debug-info-location: '' }
+body:             |
+  bb.0.entry:
+    successors: %bb.1(0x40000000), %bb.2(0x40000000)
+    liveins: $edi, $edx, $esi, $rbp, $rbx
+
+    DBG_VALUE $edi, $noreg, !16, !DIExpression(), debug-location !20
+    DBG_VALUE $esi, $noreg, !17, !DIExpression(), debug-location !20
+    DBG_VALUE $edx, $noreg, !18, !DIExpression(), debug-location !20
+    frame-setup PUSH64r killed $rbp, implicit-def $rsp, implicit $rsp
+    CFI_INSTRUCTION def_cfa_offset 16
+    frame-setup PUSH64r killed $rbx, implicit-def $rsp, implicit $rsp
+    CFI_INSTRUCTION def_cfa_offset 24
+    frame-setup PUSH64r undef $rax, implicit-def $rsp, implicit $rsp
+    CFI_INSTRUCTION def_cfa_offset 32
+    CFI_INSTRUCTION offset $rbx, -24
+    CFI_INSTRUCTION offset $rbp, -16
+    $ebp = MOV32rr $edx
+    DBG_VALUE $ebp, $noreg, !18, !DIExpression(), debug-location !20
+    renamable $edi = KILL $edi, implicit-def $rdi
+    DBG_VALUE $edi, $noreg, !16, !DIExpression(), debug-location !20
+    renamable $edx = LEA64_32r killed renamable $rdi, 1, $noreg, 2, $noreg, debug-location !21
+    DBG_VALUE $edx, $noreg, !19, !DIExpression(), debug-location !20
+    $edi = MOV32ri 5, debug-location !22
+    CMP32ri8 renamable $ebp, 16, implicit-def $eflags, debug-location !23
+    JCC_1 %bb.2, 15, implicit killed $eflags, debug-location !25
+
+  bb.1.if.then:
+    successors: %bb.3(0x80000000)
+    liveins: $ebp, $ebx, $esi
+
+    $ebx = MOV32rr $esi
+    DBG_VALUE $ebx, $noreg, !17, !DIExpression(), debug-location !20
+    $esi = MOV32ri 5, debug-location !28
+    $ebx = MOV32ri 1
+    JMP_1 %bb.3
+
+  bb.2.if.else:
+    successors: %bb.3(0x80000000)
+    liveins: $ebp, $ebx, $esi
+
+    $ebx = MOV32rr $esi
+    DBG_VALUE $ebx, $noreg, !17, !DIExpression(), debug-location !20
+    $esi = MOV32ri 1, debug-location !32
+    $ebx = MOV32ri 2
+
+  bb.3.if.end:
+    liveins: $ebx, $edi, $ebp
+
+    $esi = MOV32rr $ebx, debug-location !33
+    $edx = MOV32rr killed $ebp, debug-location !33
+    CALL64pcrel32 @fn1, csr_64, implicit $rsp, implicit $ssp, implicit $edi, implicit $esi, implicit $edx, implicit-def $rsp, implicit-def $ssp, debug-location !33
+    DBG_VALUE $ebx, $noreg, !17, !DIExpression(), debug-location !20
+    $eax = MOV32rr killed $ebx, debug-location !34
+    $rsp = frame-destroy ADD64ri8 $rsp, 8, implicit-def dead $eflags, debug-location !34
+    CFI_INSTRUCTION def_cfa_offset 24, debug-location !34
+    $rbx = frame-destroy POP64r implicit-def $rsp, implicit $rsp, debug-location !34
+    CFI_INSTRUCTION def_cfa_offset 16, debug-location !34
+    $rbp = frame-destroy POP64r implicit-def $rsp, implicit $rsp, debug-location !34
+    CFI_INSTRUCTION def_cfa_offset 8, debug-location !34
+    RETQ killed $eax, debug-location !34
+
+...
diff --git a/llvm/test/DebugInfo/MIR/X86/kill-entry-value-after-diamond-bbs.mir b/llvm/test/DebugInfo/MIR/X86/kill-entry-value-after-diamond-bbs.mir
new file mode 100644
--- /dev/null
+++ b/llvm/test/DebugInfo/MIR/X86/kill-entry-value-after-diamond-bbs.mir
@@ -0,0 +1,180 @@
+# RUN: llc -debug-entry-values -run-pass=livedebugvalues -march=x86-64 -o - %s | FileCheck %s
+#
+# The test case was artificially adjusted, in order to make proper diamond basic
+# block structure relevant to the debug entry values clobbering.
+#
+# CHECK: ![[ARG_B:.*]] = !DILocalVariable(name: "b"
+# CHECK: bb.0.entry
+# CHECK: DBG_VALUE $esi, $noreg, ![[ARG_B]], !DIExpression()
+# CHECK: bb.1.if.then
+# CHECK: DBG_VALUE $esi, $noreg, ![[ARG_B]], !DIExpression()
+# CHECK: $ebx = MOV32rr $esi
+# CHECK-NEXT: DBG_VALUE $ebx, $noreg, ![[ARG_B]], !DIExpression()
+# CHECK-NEXT: $esi = MOV32ri 5
+# CHECK-NEXT: $ebx = MOV32ri 1
+# CHECK-NEXT: DBG_VALUE $esi, $noreg, ![[ARG_B]], !DIExpression(DW_OP_LLVM_entry_value, 1)
+# CHECK: bb.2.if.else
+# CHECK: DBG_VALUE $esi, $noreg, ![[ARG_B]], !DIExpression()
+# CHECK: $ebp = MOV32rr $esi
+# CHECK: DBG_VALUE $ebp, $noreg, ![[ARG_B]], !DIExpression()
+# CHECK-NEXT: $esi = MOV32ri 1
+# CHECK-NEXT: $ebp = MOV32ri 2
+# CHECK-NEXT: DBG_VALUE $esi, $noreg, ![[ARG_B]], !DIExpression(DW_OP_LLVM_entry_value, 1)
+# CHECK: bb.3.if.end
+# CHECK-NOT: DBG_VALUE $esi, $noreg, ![[ARG_B]], !DIExpression(DW_OP_LLVM_entry_value, 1)
+#
+--- |
+  ; ModuleID = 'test.c'
+  source_filename = "test.c"
+  target datalayout = "e-m:e-p270:32:32-p271:32:32-p272:64:64-i64:64-f80:128-n8:16:32:64-S128"
+  target triple = "x86_64-unknown-linux-gnu"
+
+  ; Function Attrs: noinline nounwind uwtable
+  define dso_local i32 @fn2(i32 %a, i32 %b, i32 %c) local_unnamed_addr !dbg !12 {
+  entry:
+    call void @llvm.dbg.value(metadata i32 %a, metadata !16, metadata !DIExpression()), !dbg !20
+    call void @llvm.dbg.value(metadata i32 %b, metadata !17, metadata !DIExpression()), !dbg !20
+    call void @llvm.dbg.value(metadata i32 %c, metadata !18, metadata !DIExpression()), !dbg !20
+    %add = add nsw i32 %a, 2, !dbg !21
+    call void @llvm.dbg.value(metadata i32 %add, metadata !19, metadata !DIExpression()), !dbg !20
+    tail call void @fn1(i32 5, i32 6, i32 %add), !dbg !22
+    %cmp = icmp slt i32 %b, 17, !dbg !23
+    br i1 %cmp, label %if.then, label %if.else, !dbg !25
+
+  if.then:                                          ; preds = %entry
+    %add1 = add nsw i32 %b, 7, !dbg !26
+    call void @llvm.dbg.value(metadata i32 %add1, metadata !17, metadata !DIExpression()), !dbg !20
+    tail call void @fn1(i32 5, i32 %add1, i32 %c), !dbg !28
+    br label %if.end, !dbg !29
+
+  if.else:                                          ; preds = %entry
+    %add2 = add nuw nsw i32 %b, 1, !dbg !30
+    call void @llvm.dbg.value(metadata i32 %add2, metadata !17, metadata !DIExpression()), !dbg !20
+    tail call void @fn1(i32 1, i32 %add2, i32 %c), !dbg !32
+    br label %if.end
+
+  if.end:                                           ; preds = %if.else, %if.then
+    %b.addr.0 = phi i32 [ %add1, %if.then ], [ %add2, %if.else ], !dbg !33
+    call void @llvm.dbg.value(metadata i32 %b.addr.0, metadata !17, metadata !DIExpression()), !dbg !20
+    ret i32 %b.addr.0, !dbg !34
+  }
+
+  declare !dbg !4 dso_local void @fn1(i32, i32, i32) local_unnamed_addr
+
+  ; Function Attrs: nounwind readnone speculatable willreturn
+  declare void @llvm.dbg.value(metadata, metadata, metadata)
+
+  !llvm.dbg.cu = !{!0}
+  !llvm.module.flags = !{!8, !9, !10}
+  !llvm.ident = !{!11}
+
+  !0 = distinct !DICompileUnit(language: DW_LANG_C99, file: !1, producer: "clang version 10.0.0", isOptimized: true, runtimeVersion: 0, emissionKind: FullDebug, enums: !2, retainedTypes: !3, nameTableKind: None)
+  !1 = !DIFile(filename: "test.c", directory: "/dir")
+  !2 = !{}
+  !3 = !{!4}
+  !4 = !DISubprogram(name: "fn1", scope: !1, file: !1, line: 1, type: !5, flags: DIFlagPrototyped, spFlags: DISPFlagOptimized, retainedNodes: !2)
+  !5 = !DISubroutineType(types: !6)
+  !6 = !{null, !7, !7, !7}
+  !7 = !DIBasicType(name: "int", size: 32, encoding: DW_ATE_signed)
+  !8 = !{i32 2, !"Dwarf Version", i32 4}
+  !9 = !{i32 2, !"Debug Info Version", i32 3}
+  !10 = !{i32 1, !"wchar_size", i32 4}
+  !11 = !{!"clang version 10.0.0"}
+  !12 = distinct !DISubprogram(name: "fn2", scope: !1, file: !1, line: 5, type: !13, scopeLine: 6, flags: DIFlagPrototyped | DIFlagAllCallsDescribed, spFlags: DISPFlagDefinition | DISPFlagOptimized, unit: !0, retainedNodes: !15)
+  !13 = !DISubroutineType(types: !14)
+  !14 = !{!7, !7, !7, !7}
+  !15 = !{!16, !17, !18, !19}
+  !16 = !DILocalVariable(name: "a", arg: 1, scope: !12, file: !1, line: 5, type: !7)
+  !17 = !DILocalVariable(name: "b", arg: 2, scope: !12, file: !1, line: 5, type: !7)
+  !18 = !DILocalVariable(name: "c", arg: 3, scope: !12, file: !1, line: 5, type: !7)
+  !19 = !DILocalVariable(name: "q", scope: !12, file: !1, line: 7, type: !7)
+  !20 = !DILocation(line: 0, scope: !12)
+  !21 = !DILocation(line: 7, column: 15, scope: !12)
+  !22 = !DILocation(line: 9, column: 5, scope: !12)
+  !23 = !DILocation(line: 11, column: 11, scope: !24)
+  !24 = distinct !DILexicalBlock(scope: !12, file: !1, line: 11, column: 9)
+  !25 = !DILocation(line: 11, column: 9, scope: !12)
+  !26 = !DILocation(line: 12, column: 13, scope: !27)
+  !27 = distinct !DILexicalBlock(scope: !24, file: !1, line: 11, column: 17)
+  !28 = !DILocation(line: 13, column: 8, scope: !27)
+  !29 = !DILocation(line: 14, column: 5, scope: !27)
+  !30 = !DILocation(line: 15, column: 13, scope: !31)
+  !31 = distinct !DILexicalBlock(scope: !24, file: !1, line: 14, column: 12)
+  !32 = !DILocation(line: 16, column: 7, scope: !31)
+  !33 = !DILocation(line: 0, scope: !24)
+  !34 = !DILocation(line: 19, column: 5, scope: !12)
+
+...
+---
+name:            fn2
+alignment:       16
+fixedStack:
+  - { id: 0, type: spill-slot, offset: -24, size: 8, alignment: 8, stack-id: default,
+      callee-saved-register: '$rbx', callee-saved-restored: true, debug-info-variable: '',
+      debug-info-expression: '', debug-info-location: '' }
+  - { id: 1, type: spill-slot, offset: -16, size: 8, alignment: 16, stack-id: default,
+      callee-saved-register: '$rbp', callee-saved-restored: true, debug-info-variable: '',
+      debug-info-expression: '', debug-info-location: '' }
+body:             |
+  bb.0.entry:
+    successors: %bb.1(0x40000000), %bb.2(0x40000000)
+    liveins: $edi, $edx, $esi, $rbp, $rbx
+
+    DBG_VALUE $edi, $noreg, !16, !DIExpression(), debug-location !20
+    DBG_VALUE $esi, $noreg, !17, !DIExpression(), debug-location !20
+    DBG_VALUE $edx, $noreg, !18, !DIExpression(), debug-location !20
+    frame-setup PUSH64r killed $rbp, implicit-def $rsp, implicit $rsp
+    CFI_INSTRUCTION def_cfa_offset 16
+    frame-setup PUSH64r killed $rbx, implicit-def $rsp, implicit $rsp
+    CFI_INSTRUCTION def_cfa_offset 24
+    frame-setup PUSH64r undef $rax, implicit-def $rsp, implicit $rsp
+    CFI_INSTRUCTION def_cfa_offset 32
+    CFI_INSTRUCTION offset $rbx, -24
+    CFI_INSTRUCTION offset $rbp, -16
+    $ebp = MOV32rr $edx
+    DBG_VALUE $ebp, $noreg, !18, !DIExpression(), debug-location !20
+    renamable $edi = KILL $edi, implicit-def $rdi
+    DBG_VALUE $edi, $noreg, !16, !DIExpression(), debug-location !20
+    renamable $edx = LEA64_32r killed renamable $rdi, 1, $noreg, 2, $noreg, debug-location !21
+    DBG_VALUE $edx, $noreg, !19, !DIExpression(), debug-location !20
+    $edi = MOV32ri 5, debug-location !22
+    CMP32ri8 renamable $ebp, 16, implicit-def $eflags, debug-location !23
+    JCC_1 %bb.2, 15, implicit killed $eflags, debug-location !25
+
+  bb.1.if.then:
+    successors: %bb.3(0x80000000)
+    liveins: $ebp, $ebx, $esi
+
+    $ebx = MOV32rr $esi
+    DBG_VALUE $ebx, $noreg, !17, !DIExpression(), debug-location !20
+    $esi = MOV32ri 5, debug-location !28
+    $ebx = MOV32ri 1
+    JMP_1 %bb.3
+
+  bb.2.if.else:
+    successors: %bb.3(0x80000000)
+    liveins: $ebp, $ebx, $esi
+
+    $ebp = MOV32rr $esi
+    DBG_VALUE $ebp, $noreg, !17, !DIExpression(), debug-location !20
+    $esi = MOV32ri 1, debug-location !32
+    $ebp = MOV32ri 2
+
+  bb.3.if.end:
+    liveins: $ebx, $edi, $ebp
+
+    $esi = MOV32rr $ebx, debug-location !33
+    $edx = MOV32rr killed $ebp, debug-location !33
+    CALL64pcrel32 @fn1, csr_64, implicit $rsp, implicit $ssp, implicit $edi, implicit $esi, implicit $edx, implicit-def $rsp, implicit-def $ssp, debug-location !33
+    DBG_VALUE $ebx, $noreg, !17, !DIExpression(), debug-location !20
+    $eax = MOV32rr killed $ebx, debug-location !34
+    $rsp = frame-destroy ADD64ri8 $rsp, 8, implicit-def dead $eflags, debug-location !34
+    CFI_INSTRUCTION def_cfa_offset 24, debug-location !34
+    $rbx = frame-destroy POP64r implicit-def $rsp, implicit $rsp, debug-location !34
+    CFI_INSTRUCTION def_cfa_offset 16, debug-location !34
+    $rbp = frame-destroy POP64r implicit-def $rsp, implicit $rsp, debug-location !34
+    CFI_INSTRUCTION def_cfa_offset 8, debug-location !34
+    RETQ killed $eax, debug-location !34
+
+...
+
diff --git a/llvm/test/DebugInfo/MIR/X86/propagate-entry-value-cross-bbs.mir b/llvm/test/DebugInfo/MIR/X86/propagate-entry-value-cross-bbs.mir
new file mode 100644
--- /dev/null
+++ b/llvm/test/DebugInfo/MIR/X86/propagate-entry-value-cross-bbs.mir
@@ -0,0 +1,184 @@
+# RUN: llc -debug-entry-values -run-pass=livedebugvalues -march=x86-64 -o - %s | FileCheck %s
+#
+#extern void fn1 (int, int, int);
+#__attribute__((noinline))
+#int
+#fn2 (int a, int b, int c) {
+#  int q = 2 + a;
+#  fn1 (5, 6, q);
+#  if (b < 17) {
+#    b = b + 7;
+#     fn1 (5, b, q);
+#  } else {
+#    b = b + 1;
+#    fn1 (1, b, q);
+#  }
+#  return b;
+#}
+# CHECK: ![[ARG_C:.*]] = !DILocalVariable(name: "c"
+# CHECK: bb.0.entry:
+# CHECK: DBG_VALUE $edx, $noreg, ![[ARG_C]], !DIExpression(DW_OP_LLVM_entry_value, 1)
+# CHECK: bb.1.if.then:
+# CHECK: DBG_VALUE $edx, $noreg, ![[ARG_C]], !DIExpression(DW_OP_LLVM_entry_value, 1)
+# CHECK: bb.2.if.else:
+# CHECK: DBG_VALUE $edx, $noreg, ![[ARG_C]], !DIExpression(DW_OP_LLVM_entry_value, 1)
+# CHECK: bb.3.if.end:
+# CHECK: DBG_VALUE $edx, $noreg, ![[ARG_C]], !DIExpression(DW_OP_LLVM_entry_value, 1)
+#
+--- |
+  ; ModuleID = 'test.c'
+  source_filename = "test.c"
+  target datalayout = "e-m:e-p270:32:32-p271:32:32-p272:64:64-i64:64-f80:128-n8:16:32:64-S128"
+  target triple = "x86_64-unknown-linux-gnu"
+
+  ; Function Attrs: noinline nounwind uwtable
+  define dso_local i32 @fn2(i32 %a, i32 %b, i32 %c) local_unnamed_addr !dbg !12 {
+  entry:
+    call void @llvm.dbg.value(metadata i32 %a, metadata !16, metadata !DIExpression()), !dbg !20
+    call void @llvm.dbg.value(metadata i32 %b, metadata !17, metadata !DIExpression()), !dbg !20
+    call void @llvm.dbg.value(metadata i32 %c, metadata !18, metadata !DIExpression()), !dbg !20
+    %add = add nsw i32 %a, 2, !dbg !21
+    call void @llvm.dbg.value(metadata i32 %add, metadata !19, metadata !DIExpression()), !dbg !20
+    tail call void @fn1(i32 5, i32 6, i32 %add), !dbg !22
+    %cmp = icmp slt i32 %b, 17, !dbg !23
+    br i1 %cmp, label %if.then, label %if.else, !dbg !25
+
+  if.then:                                          ; preds = %entry
+    %add1 = add nsw i32 %b, 7, !dbg !26
+    call void @llvm.dbg.value(metadata i32 %add1, metadata !17, metadata !DIExpression()), !dbg !20
+    tail call void @fn1(i32 5, i32 %add1, i32 %add), !dbg !28
+    br label %if.end, !dbg !29
+
+  if.else:                                          ; preds = %entry
+    %add2 = add nuw nsw i32 %b, 1, !dbg !30
+    call void @llvm.dbg.value(metadata i32 %add2, metadata !17, metadata !DIExpression()), !dbg !20
+    tail call void @fn1(i32 1, i32 %add2, i32 %add), !dbg !32
+    br label %if.end
+
+  if.end:                                           ; preds = %if.else, %if.then
+    %b.addr.0 = phi i32 [ %add1, %if.then ], [ %add2, %if.else ], !dbg !33
+    call void @llvm.dbg.value(metadata i32 %b.addr.0, metadata !17, metadata !DIExpression()), !dbg !20
+    ret i32 %b.addr.0, !dbg !34
+  }
+
+  declare !dbg !4 dso_local void @fn1(i32, i32, i32) local_unnamed_addr
+
+  ; Function Attrs: nounwind readnone speculatable willreturn
+  declare void @llvm.dbg.value(metadata, metadata, metadata)
+
+  !llvm.dbg.cu = !{!0}
+  !llvm.module.flags = !{!8, !9, !10}
+  !llvm.ident = !{!11}
+
+  !0 = distinct !DICompileUnit(language: DW_LANG_C99, file: !1, producer: "clang version 10.0.0", isOptimized: true, runtimeVersion: 0, emissionKind: FullDebug, enums: !2, retainedTypes: !3, nameTableKind: None)
+  !1 = !DIFile(filename: "test.c", directory: "/")
+  !2 = !{}
+  !3 = !{!4}
+  !4 = !DISubprogram(name: "fn1", scope: !1, file: !1, line: 1, type: !5, flags: DIFlagPrototyped, spFlags: DISPFlagOptimized, retainedNodes: !2)
+  !5 = !DISubroutineType(types: !6)
+  !6 = !{null, !7, !7, !7}
+  !7 = !DIBasicType(name: "int", size: 32, encoding: DW_ATE_signed)
+  !8 = !{i32 2, !"Dwarf Version", i32 4}
+  !9 = !{i32 2, !"Debug Info Version", i32 3}
+  !10 = !{i32 1, !"wchar_size", i32 4}
+  !11 = !{!"clang version 10.0.0"}
+  !12 = distinct !DISubprogram(name: "fn2", scope: !1, file: !1, line: 5, type: !13, scopeLine: 6, flags: DIFlagPrototyped | DIFlagAllCallsDescribed, spFlags: DISPFlagDefinition | DISPFlagOptimized, unit: !0, retainedNodes: !15)
+  !13 = !DISubroutineType(types: !14)
+  !14 = !{!7, !7, !7, !7}
+  !15 = !{!16, !17, !18, !19}
+  !16 = !DILocalVariable(name: "a", arg: 1, scope: !12, file: !1, line: 5, type: !7)
+  !17 = !DILocalVariable(name: "b", arg: 2, scope: !12, file: !1, line: 5, type: !7)
+  !18 = !DILocalVariable(name: "c", arg: 3, scope: !12, file: !1, line: 5, type: !7)
+  !19 = !DILocalVariable(name: "q", scope: !12, file: !1, line: 7, type: !7)
+  !20 = !DILocation(line: 0, scope: !12)
+  !21 = !DILocation(line: 7, column: 15, scope: !12)
+  !22 = !DILocation(line: 9, column: 5, scope: !12)
+  !23 = !DILocation(line: 11, column: 11, scope: !24)
+  !24 = distinct !DILexicalBlock(scope: !12, file: !1, line: 11, column: 9)
+  !25 = !DILocation(line: 11, column: 9, scope: !12)
+  !26 = !DILocation(line: 12, column: 13, scope: !27)
+  !27 = distinct !DILexicalBlock(scope: !24, file: !1, line: 11, column: 17)
+  !28 = !DILocation(line: 13, column: 8, scope: !27)
+  !29 = !DILocation(line: 14, column: 5, scope: !27)
+  !30 = !DILocation(line: 15, column: 13, scope: !31)
+  !31 = distinct !DILexicalBlock(scope: !24, file: !1, line: 14, column: 12)
+  !32 = !DILocation(line: 16, column: 7, scope: !31)
+  !33 = !DILocation(line: 0, scope: !24)
+  !34 = !DILocation(line: 19, column: 5, scope: !12)
+
+...
+---
+name:            fn2
+alignment:       16
+callSites:
+  - { bb: 0, offset: 20, fwdArgRegs:
+      - { arg: 0, reg: '$edi' }
+      - { arg: 1, reg: '$esi' }
+      - { arg: 2, reg: '$edx' } }
+  - { bb: 3, offset: 2, fwdArgRegs:
+      - { arg: 0, reg: '$edi' }
+      - { arg: 1, reg: '$esi' }
+      - { arg: 2, reg: '$edx' } }
+body:             |
+  bb.0.entry:
+    successors: %bb.1(0x40000000), %bb.2(0x40000000)
+    liveins: $edi, $esi, $rbp, $rbx
+
+    DBG_VALUE $edi, $noreg, !16, !DIExpression(), debug-location !20
+    DBG_VALUE $esi, $noreg, !17, !DIExpression(), debug-location !20
+    DBG_VALUE $edx, $noreg, !18, !DIExpression(), debug-location !20
+    frame-setup PUSH64r killed $rbp, implicit-def $rsp, implicit $rsp
+    CFI_INSTRUCTION def_cfa_offset 16
+    frame-setup PUSH64r killed $rbx, implicit-def $rsp, implicit $rsp
+    CFI_INSTRUCTION def_cfa_offset 24
+    frame-setup PUSH64r undef $rax, implicit-def $rsp, implicit $rsp
+    CFI_INSTRUCTION def_cfa_offset 32
+    CFI_INSTRUCTION offset $rbx, -24
+    CFI_INSTRUCTION offset $rbp, -16
+    $ebx = MOV32rr $esi
+    DBG_VALUE $ebx, $noreg, !17, !DIExpression(), debug-location !20
+    $ebp = MOV32rr $edi
+    DBG_VALUE $ebp, $noreg, !16, !DIExpression(), debug-location !20
+    renamable $ebp = nsw ADD32ri8 killed renamable $ebp, 2, implicit-def dead $eflags, debug-location !21
+    DBG_VALUE $ebp, $noreg, !19, !DIExpression(), debug-location !20
+    $edi = MOV32ri 5, debug-location !22
+    $esi = MOV32ri 6, debug-location !22
+    $edx = MOV32rr $ebp, debug-location !22
+    CALL64pcrel32 @fn1, csr_64, implicit $rsp, implicit $ssp, implicit $edi, implicit $esi, implicit killed $edx, implicit-def $rsp, implicit-def $ssp, debug-location !22
+    CMP32ri8 renamable $ebx, 16, implicit-def $eflags, debug-location !23
+    JCC_1 %bb.2, 15, implicit killed $eflags, debug-location !25
+
+  bb.1.if.then:
+    successors: %bb.3(0x80000000)
+    liveins: $ebp, $ebx
+
+    renamable $ebx = nsw ADD32ri8 killed renamable $ebx, 7, implicit-def dead $eflags, debug-location !26
+    DBG_VALUE $ebx, $noreg, !17, !DIExpression(), debug-location !20
+    $edi = MOV32ri 5, debug-location !28
+    JMP_1 %bb.3
+
+  bb.2.if.else:
+    successors: %bb.3(0x80000000)
+    liveins: $ebp, $ebx
+
+    renamable $ebx = nuw nsw ADD32ri8 killed renamable $ebx, 1, implicit-def dead $eflags, debug-location !30
+    DBG_VALUE $ebx, $noreg, !17, !DIExpression(), debug-location !20
+    $edi = MOV32ri 1, debug-location !32
+
+  bb.3.if.end:
+    liveins: $ebx, $edi, $ebp
+
+    $esi = MOV32rr $ebx, debug-location !33
+    $edx = MOV32rr killed $ebp, debug-location !33
+    CALL64pcrel32 @fn1, csr_64, implicit $rsp, implicit $ssp, implicit $edi, implicit $esi, implicit killed $edx, implicit-def $rsp, implicit-def $ssp, debug-location !33
+    DBG_VALUE $ebx, $noreg, !17, !DIExpression(), debug-location !20
+    $eax = MOV32rr killed $ebx, debug-location !34
+    $rsp = frame-destroy ADD64ri8 $rsp, 8, implicit-def dead $eflags, debug-location !34
+    CFI_INSTRUCTION def_cfa_offset 24, debug-location !34
+    $rbx = frame-destroy POP64r implicit-def $rsp, implicit $rsp, debug-location !34
+    CFI_INSTRUCTION def_cfa_offset 16, debug-location !34
+    $rbp = frame-destroy POP64r implicit-def $rsp, implicit $rsp, debug-location !34
+    CFI_INSTRUCTION def_cfa_offset 8, debug-location !34
+    RETQ killed $eax, debug-location !34
+
+...