diff --git a/llvm/include/llvm/IR/DebugInfoMetadata.h
 b/llvm/include/llvm/IR/DebugInfoMetadata.h
--- a/llvm/include/llvm/IR/DebugInfoMetadata.h
+++ b/llvm/include/llvm/IR/DebugInfoMetadata.h
@@ -2597,6 +2597,15 @@
   static DIExpression *appendOpsToArg(const DIExpression *Expr,
                                       ArrayRef<uint64_t> Ops, uint64_t ArgNo);
 
+  /// Create a copy of \p Expr with each instance of
+  /// `DW_OP_LLVM_arg, \p OldArg` replaced with `DW_OP_LLVM_arg, \p NewArg`,
+  /// and each instance of `DW_OP_LLVM_arg, Arg` with `DW_OP_LLVM_arg, Arg - 1`
+  /// for all Arg > \p OldArg.
+  /// This is used when replacing one of the operands of a debug value list
+  /// with another operand in the same list and deleting the old operand.
+  static DIExpression *replaceArg(const DIExpression *Expr, uint64_t OldArg,
+	  uint64_t NewArg);
+
   /// Create a DIExpression to describe one part of an aggregate variable that
   /// is fragmented across multiple Values. The DW_OP_LLVM_fragment operation
   /// will be appended to the elements of \c Expr. If \c Expr already contains
diff --git a/llvm/lib/IR/DebugInfoMetadata.cpp
 b/llvm/lib/IR/DebugInfoMetadata.cpp
--- a/llvm/lib/IR/DebugInfoMetadata.cpp
+++ b/llvm/lib/IR/DebugInfoMetadata.cpp
@@ -1188,6 +1188,28 @@
   return DIExpression::get(Expr->getContext(), NewOps);
 }
 
+DIExpression *DIExpression::replaceArg(const DIExpression *Expr,
+                                       uint64_t OldArg, uint64_t NewArg) {
+  assert(Expr && "Can't replace args in this expression");
+
+  SmallVector<uint64_t, 8> NewOps;
+
+  for (auto Op : Expr->expr_ops()) {
+    if (Op.getOp() != dwarf::DW_OP_LLVM_arg || Op.getArg(0) < OldArg) {
+      Op.appendToVector(NewOps);
+      continue;
+    }
+    NewOps.push_back(dwarf::DW_OP_LLVM_arg);
+    uint64_t Arg = Op.getArg(0) == OldArg ? NewArg : Op.getArg(0);
+    // OldArg has been deleted from the Op list, so decrement all indices
+    // greater than it.
+    if (Arg > OldArg)
+      --Arg;
+    NewOps.push_back(Arg);
+  }
+  return DIExpression::get(Expr->getContext(), NewOps);
+}
+
 DIExpression *DIExpression::prependOpcodes(const DIExpression *Expr,
                                            SmallVectorImpl<uint64_t> &Ops,
                                            bool StackValue,
diff --git a/llvm/unittests/IR/MetadataTest.cpp
 b/llvm/unittests/IR/MetadataTest.cpp
--- a/llvm/unittests/IR/MetadataTest.cpp
+++ b/llvm/unittests/IR/MetadataTest.cpp
@@ -2655,7 +2655,7 @@
   EXPECT_VALID_FRAGMENT(0, 32, dwarf::DW_OP_deref);
   EXPECT_VALID_FRAGMENT(0, 32, dwarf::DW_OP_LLVM_fragment, 0, 32);
   EXPECT_VALID_FRAGMENT(16, 16, dwarf::DW_OP_LLVM_fragment, 0, 32);
-
+  
   // Invalid fragment expressions (incompatible ops).
   EXPECT_INVALID_FRAGMENT(0, 32, dwarf::DW_OP_constu, 6, dwarf::DW_OP_plus);
   EXPECT_INVALID_FRAGMENT(0, 32, dwarf::DW_OP_constu, 14, dwarf::DW_OP_minus);
@@ -2668,6 +2668,34 @@
 #undef EXPECT_INVALID_FRAGMENT
 }
 
+TEST_F(DIExpressionTest, replaceArg) {
+#define EXPECT_REPLACE_ARG_EQ(Expr, OldArg, NewArg, ...)                       \
+  do {                                                                         \
+    ArrayRef<uint64_t> Expected({__VA_ARGS__});                                \
+    DIExpression* Expression = DIExpression::replaceArg(Expr, OldArg, NewArg); \
+	EXPECT_EQ(Expression->getElements(), Expected);                            \
+  } while (false)
+
+
+	auto N = DIExpression::get(Context, {
+		dwarf::DW_OP_LLVM_arg, 0, dwarf::DW_OP_LLVM_arg, 1, dwarf::DW_OP_plus,
+		dwarf::DW_OP_LLVM_arg, 2, dwarf::DW_OP_mul});
+	EXPECT_REPLACE_ARG_EQ(N, 0, 1,
+		dwarf::DW_OP_LLVM_arg, 0, dwarf::DW_OP_LLVM_arg, 0, dwarf::DW_OP_plus,
+		dwarf::DW_OP_LLVM_arg, 1, dwarf::DW_OP_mul);
+	EXPECT_REPLACE_ARG_EQ(N, 0, 2,
+		dwarf::DW_OP_LLVM_arg, 1, dwarf::DW_OP_LLVM_arg, 0, dwarf::DW_OP_plus,
+		dwarf::DW_OP_LLVM_arg, 1, dwarf::DW_OP_mul);
+	EXPECT_REPLACE_ARG_EQ(N, 2, 0,
+		dwarf::DW_OP_LLVM_arg, 0, dwarf::DW_OP_LLVM_arg, 1, dwarf::DW_OP_plus,
+		dwarf::DW_OP_LLVM_arg, 0, dwarf::DW_OP_mul);
+	EXPECT_REPLACE_ARG_EQ(N, 2, 1,
+		dwarf::DW_OP_LLVM_arg, 0, dwarf::DW_OP_LLVM_arg, 1, dwarf::DW_OP_plus,
+		dwarf::DW_OP_LLVM_arg, 1, dwarf::DW_OP_mul);
+
+#undef EXPECT_REPLACE_ARG_EQ
+}
+
 typedef MetadataTest DIObjCPropertyTest;
 
 TEST_F(DIObjCPropertyTest, get) {