Index: llvm/include/llvm/IR/Metadata.h
===================================================================
--- llvm/include/llvm/IR/Metadata.h
+++ llvm/include/llvm/IR/Metadata.h
@@ -1001,6 +1001,8 @@
     return cast<T>(N.release()->replaceWithDistinctImpl());
   }
 
+  void replaceName(MDString *NewName) { setOperand(1, NewName); }
+
 private:
   MDNode *replaceWithPermanentImpl();
   MDNode *replaceWithUniquedImpl();
Index: llvm/include/llvm/Transforms/Utils/BasicBlockUtils.h
===================================================================
--- llvm/include/llvm/Transforms/Utils/BasicBlockUtils.h
+++ llvm/include/llvm/Transforms/Utils/BasicBlockUtils.h
@@ -50,6 +50,8 @@
                        SmallVectorImpl<DominatorTree::UpdateType> *Updates,
                        bool KeepOneInputPHIs = false);
 
+void DeleteUselessDbgInfo(ArrayRef<BasicBlock *> ToRemovedBBs);
+
 /// Delete the specified block, which must have no predecessors.
 void DeleteDeadBlock(BasicBlock *BB, DomTreeUpdater *DTU = nullptr,
                      bool KeepOneInputPHIs = false);
Index: llvm/lib/Transforms/Coroutines/CoroFrame.cpp
===================================================================
--- llvm/lib/Transforms/Coroutines/CoroFrame.cpp
+++ llvm/lib/Transforms/Coroutines/CoroFrame.cpp
@@ -29,6 +29,7 @@
 #include "llvm/IR/InstIterator.h"
 #include "llvm/Support/CommandLine.h"
 #include "llvm/Support/Debug.h"
+#include "llvm/Support/ErrorHandling.h"
 #include "llvm/Support/MathExtras.h"
 #include "llvm/Support/OptimizedStructLayout.h"
 #include "llvm/Support/circular_raw_ostream.h"
@@ -1052,6 +1053,20 @@
   return CleanupRet;
 }
 
+static void getNewValueStorage(Value *V, Value *&NewValue, DIExpression *&Expr) {
+  assert(V && "V should not be null");
+  while (true) {
+    if (auto *GEPInst = dyn_cast<GetElementPtrInst>(V)) {
+      Expr = llvm::salvageDebugInfoImpl(*GEPInst, Expr, false);
+      V = GEPInst->getOperand(0);
+    } else if (auto *BCInst = dyn_cast<BitCastInst>(V))
+      V = BCInst->getOperand(0);
+    else
+      break;
+  }
+  NewValue = V;
+}
+
 // Replace all alloca and SSA values that are accessed across suspend points
 // with GetElementPointer from coroutine frame + loads and stores. Create an
 // AllocaSpillBB that will become the new entry block for the resume parts of
@@ -1077,6 +1092,7 @@
 static Instruction *insertSpills(const FrameDataInfo &FrameData,
                                  coro::Shape &Shape) {
   auto *CB = Shape.CoroBegin;
+  auto *M = CB->getModule();
   LLVMContext &C = CB->getContext();
   IRBuilder<> Builder(CB->getNextNode());
   StructType *FrameTy = Shape.FrameTy;
@@ -1084,6 +1100,8 @@
   auto *FramePtr =
       cast<Instruction>(Builder.CreateBitCast(CB, FramePtrTy, "FramePtr"));
   DominatorTree DT(*CB->getFunction());
+  // copy dbg from entry block if the dbg intrinsic existed
+  std::unique_ptr<DIBuilder> DIB = std::make_unique<DIBuilder>(*M, false);
 
   // Create a GEP with the given index into the coroutine frame for the original
   // value Orig. Appends an extra 0 index for array-allocas, preserving the
@@ -1124,6 +1142,10 @@
     // Create a store instruction storing the value into the
     // coroutine frame.
     Instruction *InsertPt = nullptr;
+    DbgVariableIntrinsic *DebugInstrinsic = nullptr;
+    SmallVector<DbgVariableIntrinsic *, 8> DbgUsers;
+    // find all dbg user
+    findDbgUsers(DbgUsers, Def);
     if (auto *Arg = dyn_cast<Argument>(Def)) {
       // For arguments, we will place the store instruction right after
       // the coroutine frame pointer instruction, i.e. bitcast of
@@ -1134,6 +1156,15 @@
       // from the coroutine function.
       Arg->getParent()->removeParamAttr(Arg->getArgNo(), Attribute::NoCapture);
 
+      // Get debug intrinsic for argument
+      auto Iter = llvm::find_if(DbgUsers, [](DbgVariableIntrinsic *Dbg) {
+        DILocalVariable *Variable = Dbg->getVariable();
+        return Variable->isParameter() && !Variable->isArtificial();
+      });
+
+      // if we get multiple results, just pick one
+      if (Iter != DbgUsers.end())
+        DebugInstrinsic = *Iter;
     } else if (auto *CSI = dyn_cast<AnyCoroSuspendInst>(Def)) {
       // Don't spill immediately after a suspend; splitting assumes
       // that the suspend will be followed by a branch.
@@ -1185,6 +1216,21 @@
         CurrentReload = Builder.CreateLoad(
             FrameTy->getElementType(FrameData.getFieldIndex(E.first)), GEP,
             E.first->getName() + Twine(".reload"));
+
+        if (DIB && DebugInstrinsic) {
+            auto *CurVar = DebugInstrinsic->getVariable();
+            assert(CurVar && "CurVar should not be null");
+            const DILocation *Loc = DebugInstrinsic->getDebugLoc().get();
+
+            // try to get scope form gep or use original one
+            Instruction *InstGEP = cast<Instruction>(GEP);
+            DIExpression *NewExpr = DIExpression::append(
+                DebugInstrinsic->getExpression(), dwarf::DW_OP_deref);
+            Value *NewValue = InstGEP;
+            getNewValueStorage(InstGEP, NewValue, NewExpr);
+            DIB->insertDbgValueIntrinsic(NewValue, CurVar, NewExpr, Loc,
+                                         cast<Instruction>(CurrentReload));
+        }
       }
 
       // If we have a single edge PHINode, remove it and replace it with a
Index: llvm/lib/Transforms/Utils/BasicBlockUtils.cpp
===================================================================
--- llvm/lib/Transforms/Utils/BasicBlockUtils.cpp
+++ llvm/lib/Transforms/Utils/BasicBlockUtils.cpp
@@ -85,6 +85,50 @@
   }
 }
 
+void llvm::DeleteUselessDbgInfo(ArrayRef<BasicBlock *> ToRemovedBBs) {
+  for (BasicBlock *BB : ToRemovedBBs) {
+    for (auto &I : *BB) {
+      if (auto *Dbg = dyn_cast_or_null<DbgVariableIntrinsic>(&I)) {
+        bool SafeToRemove = false;
+        auto *Variable = Dbg->getVariable();
+        if (Variable == nullptr)
+          continue;
+
+        auto *MetaVal = MetadataAsValue::get(BB->getContext(), Variable);
+        do {
+          // 1. if user is empty, we can safe to remove it
+          if (MetaVal->user_empty()) {
+            SafeToRemove = true;
+            break;
+          }
+
+          // 2. if has use, we will keep it.
+          SafeToRemove = true;
+          for (Use &U : MetaVal->uses()) {
+            if (auto *I = dyn_cast_or_null<Instruction>(U.getUser())) {
+              BasicBlock *CurBB = I->getParent();
+              auto FindBBFn = [&](BasicBlock *BB) { return CurBB == BB; };
+              if (!llvm::any_of(ToRemovedBBs, FindBBFn)) {
+                SafeToRemove = false;
+                break;
+              }
+            }
+          }
+        } while (0);
+
+        if (SafeToRemove) {
+          // TODO: it is better to remove the useless metadata from Module, but
+          // we can not do it now
+          LLVM_DEBUG(dbgs() << "remove metadata:\n"; MetaVal->dump(););
+          std::string Name = Variable->getName().data();
+          Name += "__fake_param_" + Name;
+          Variable->replaceName(MDString::get(BB->getContext(), Name));
+        }
+      }
+    }
+  }
+}
+
 void llvm::DeleteDeadBlock(BasicBlock *BB, DomTreeUpdater *DTU,
                            bool KeepOneInputPHIs) {
   DeleteDeadBlocks({BB}, DTU, KeepOneInputPHIs);
@@ -101,6 +145,9 @@
       assert(Dead.count(Pred) && "All predecessors must be dead!");
 #endif
 
+  // remove dbgs
+  DeleteUselessDbgInfo(BBs);
+
   SmallVector<DominatorTree::UpdateType, 4> Updates;
   DetatchDeadBlocks(BBs, DTU ? &Updates : nullptr, KeepOneInputPHIs);
 
Index: llvm/lib/Transforms/Utils/Local.cpp
===================================================================
--- llvm/lib/Transforms/Utils/Local.cpp
+++ llvm/lib/Transforms/Utils/Local.cpp
@@ -2380,6 +2380,7 @@
   std::vector<DominatorTree::UpdateType> Updates;
   for (auto *BB : DeadBlockSet) {
     SmallSetVector<BasicBlock *, 8> UniqueSuccessors;
+    DeleteUselessDbgInfo({BB});
     for (BasicBlock *Successor : successors(BB)) {
       if (!DeadBlockSet.count(Successor))
         Successor->removePredecessor(BB);