diff --git a/llvm/lib/CodeGen/GlobalISel/RegBankSelect.cpp b/llvm/lib/CodeGen/GlobalISel/RegBankSelect.cpp
--- a/llvm/lib/CodeGen/GlobalISel/RegBankSelect.cpp
+++ b/llvm/lib/CodeGen/GlobalISel/RegBankSelect.cpp
@@ -603,6 +603,9 @@
       MRI->setRegBank(Reg, *ValMapping.BreakDown[0].RegBank);
       break;
     case RepairingPlacement::Insert:
+      // Don't insert additional instruction for debug instruction.
+      if (MI.isDebugInstr())
+        break;
       OpdMapper.createVRegs(OpIdx);
       if (!repairReg(MO, ValMapping, RepairPt, OpdMapper.getVRegs(OpIdx)))
         return false;
@@ -716,9 +719,25 @@
       if (MI.isInlineAsm())
         continue;
 
-      // Ignore debug info.
-      if (MI.isDebugInstr())
-        continue;
+      if (MI.isDebugInstr()) {
+        bool Ignore = false;
+        for (MachineOperand &MO : MI.operands()) {
+          if (!MO.isReg())
+            continue;
+          Register Reg = MO.getReg();
+          if (!Reg)
+            continue;
+          // If there is physical register or virtual register that has been
+          // assigned to a register class, ignore debug info.
+          LLT Ty = MRI->getType(Reg);
+          if (!Ty.isValid()) {
+            Ignore = true;
+            break;
+          }
+        }
+        if (Ignore)
+          continue;
+      }
 
       // Ignore IMPLICIT_DEF which must have a regclass.
       if (MI.isImplicitDef())
diff --git a/llvm/lib/Target/AArch64/GISel/AArch64InstructionSelector.cpp b/llvm/lib/Target/AArch64/GISel/AArch64InstructionSelector.cpp
--- a/llvm/lib/Target/AArch64/GISel/AArch64InstructionSelector.cpp
+++ b/llvm/lib/Target/AArch64/GISel/AArch64InstructionSelector.cpp
@@ -907,6 +907,51 @@
           getMinClassForRegBank(DstRegBank, DstSize, true)};
 }
 
+static bool selectDebugInstr(MachineInstr &I, MachineRegisterInfo &MRI,
+                             const RegisterBankInfo &RBI) {
+  bool Ignore = false;
+  for (MachineOperand &MO : I.operands()) {
+    if (!MO.isReg())
+      continue;
+    Register Reg = MO.getReg();
+    if (!Reg)
+      continue;
+    LLT Ty = MRI.getType(Reg);
+    // If there is physical register or virutal register that has been
+    // assigned to a register class, just bail out. This logic is aligned
+    // to RegBankSelect when setting register bank for debug instructions.
+    if (!Ty.isValid()) {
+      Ignore = true;
+      break;
+    }
+  }
+  if (Ignore)
+    return true;
+  for (MachineOperand &MO : I.operands()) {
+    if (!MO.isReg())
+      continue;
+    Register Reg = MO.getReg();
+    if (!Reg)
+      continue;
+    LLT Ty = MRI.getType(Reg);
+    const RegClassOrRegBank &RegClassOrBank = MRI.getRegClassOrRegBank(Reg);
+    const TargetRegisterClass *RC =
+        RegClassOrBank.dyn_cast<const TargetRegisterClass *>();
+    if (!RC) {
+      const RegisterBank &RB = *RegClassOrBank.get<const RegisterBank *>();
+      RC = getRegClassForTypeOnBank(Ty, RB);
+      if (!RC) {
+        LLVM_DEBUG(
+            dbgs() << "Warning: DBG_VALUE operand has unexpected size/bank\n");
+        break;
+      }
+    }
+    RBI.constrainGenericRegister(Reg, *RC, MRI);
+  }
+
+  return true;
+}
+
 static bool selectCopy(MachineInstr &I, const TargetInstrInfo &TII,
                        MachineRegisterInfo &MRI, const TargetRegisterInfo &TRI,
                        const RegisterBankInfo &RBI) {
@@ -2382,6 +2427,9 @@
     if (I.isCopy())
       return selectCopy(I, TII, MRI, TRI, RBI);
 
+    if (I.isDebugInstr())
+      return selectDebugInstr(I, MRI, RBI);
+
     return true;
   }
 
diff --git a/llvm/lib/Target/X86/X86InstructionSelector.cpp b/llvm/lib/Target/X86/X86InstructionSelector.cpp
--- a/llvm/lib/Target/X86/X86InstructionSelector.cpp
+++ b/llvm/lib/Target/X86/X86InstructionSelector.cpp
@@ -94,6 +94,7 @@
                   MachineFunction &MF) const;
   bool selectUadde(MachineInstr &I, MachineRegisterInfo &MRI,
                    MachineFunction &MF) const;
+  bool selectDebugInstr(MachineInstr &I, MachineRegisterInfo &MRI) const;
   bool selectCopy(MachineInstr &I, MachineRegisterInfo &MRI) const;
   bool selectUnmergeValues(MachineInstr &I, MachineRegisterInfo &MRI,
                            MachineFunction &MF);
@@ -230,6 +231,51 @@
   llvm_unreachable("Unknown RegClass for PhysReg!");
 }
 
+bool X86InstructionSelector::selectDebugInstr(MachineInstr &I,
+                                              MachineRegisterInfo &MRI) const {
+  bool Ignore = false;
+  for (MachineOperand &MO : I.operands()) {
+    if (!MO.isReg())
+      continue;
+    Register Reg = MO.getReg();
+    if (!Reg)
+      continue;
+    LLT Ty = MRI.getType(Reg);
+    // If there is physical register or virutal register that has been
+    // assigned to a register class, just bail out. This logic is aligned
+    // to RegBankSelect when setting register bank for debug instructions.
+    if (!Ty.isValid()) {
+      Ignore = true;
+      break;
+    }
+  }
+  if (Ignore)
+    return true;
+  for (MachineOperand &MO : I.operands()) {
+    if (!MO.isReg())
+      continue;
+    Register Reg = MO.getReg();
+    if (!Reg)
+      continue;
+    LLT Ty = MRI.getType(Reg);
+    const RegClassOrRegBank &RegClassOrBank = MRI.getRegClassOrRegBank(Reg);
+    const TargetRegisterClass *RC =
+        RegClassOrBank.dyn_cast<const TargetRegisterClass *>();
+    if (!RC) {
+      const RegisterBank &RB = *RegClassOrBank.get<const RegisterBank *>();
+      RC = getRegClass(Ty, RB);
+      if (!RC) {
+        LLVM_DEBUG(
+            dbgs() << "Warning: DBG_VALUE operand has unexpected size/bank\n");
+        break;
+      }
+    }
+    RBI.constrainGenericRegister(Reg, *RC, MRI);
+  }
+
+  return true;
+}
+
 // Set X86 Opcode and constrain DestReg.
 bool X86InstructionSelector::selectCopy(MachineInstr &I,
                                         MachineRegisterInfo &MRI) const {
@@ -326,6 +372,9 @@
     if (I.isCopy())
       return selectCopy(I, MRI);
 
+    if (I.isDebugInstr())
+      return selectDebugInstr(I, MRI);
+
     return true;
   }
 
diff --git a/llvm/lib/Target/X86/X86RegisterBankInfo.cpp b/llvm/lib/Target/X86/X86RegisterBankInfo.cpp
--- a/llvm/lib/Target/X86/X86RegisterBankInfo.cpp
+++ b/llvm/lib/Target/X86/X86RegisterBankInfo.cpp
@@ -114,7 +114,7 @@
   unsigned NumOperands = MI.getNumOperands();
   for (unsigned Idx = 0; Idx < NumOperands; ++Idx) {
     auto &MO = MI.getOperand(Idx);
-    if (!MO.isReg())
+    if (!MO.isReg() || !MO.getReg())
       OpRegBankIdx[Idx] = PMI_None;
     else
       OpRegBankIdx[Idx] = getPartialMappingIdx(MRI.getType(MO.getReg()), isFP);
@@ -130,6 +130,8 @@
   for (unsigned Idx = 0; Idx < NumOperands; ++Idx) {
     if (!MI.getOperand(Idx).isReg())
       continue;
+    if (!MI.getOperand(Idx).getReg())
+      continue;
 
     auto Mapping = getValueMapping(OpRegBankIdx[Idx], 1);
     if (!Mapping->isValid())
diff --git a/llvm/test/CodeGen/AArch64/GlobalISel/select-dbg-value.mir b/llvm/test/CodeGen/AArch64/GlobalISel/select-dbg-value.mir
--- a/llvm/test/CodeGen/AArch64/GlobalISel/select-dbg-value.mir
+++ b/llvm/test/CodeGen/AArch64/GlobalISel/select-dbg-value.mir
@@ -43,10 +43,12 @@
   bb.0:
     liveins: $w0
     ; CHECK-LABEL: name: test_dbg_value
-    ; CHECK: [[COPY:%[0-9]+]]:gpr32 = COPY $w0
-    ; CHECK: [[ADDWrr:%[0-9]+]]:gpr32 = ADDWrr [[COPY]], [[COPY]]
-    ; CHECK: $w0 = COPY [[ADDWrr]]
-    ; CHECK: DBG_VALUE [[ADDWrr]], $noreg, !7, !DIExpression(), debug-location !9
+    ; CHECK: liveins: $w0
+    ; CHECK-NEXT: {{  $}}
+    ; CHECK-NEXT: [[COPY:%[0-9]+]]:gpr32 = COPY $w0
+    ; CHECK-NEXT: [[ADDWrr:%[0-9]+]]:gpr32 = ADDWrr [[COPY]], [[COPY]]
+    ; CHECK-NEXT: $w0 = COPY [[ADDWrr]]
+    ; CHECK-NEXT: DBG_VALUE [[ADDWrr]], $noreg, !7, !DIExpression(), debug-location !9
     %0:gpr(s32) = COPY $w0
     %1:gpr(s32) = G_ADD %0, %0
     $w0 = COPY %1(s32)
@@ -61,8 +63,9 @@
   bb.0:
     liveins: $w0
     ; CHECK-LABEL: name: test_dbg_value_dead
-    ; CHECK-NOT: COPY
-    ; CHECK: DBG_VALUE %0:gpr, $noreg, !7, !DIExpression(), debug-location !9
+    ; CHECK: liveins: $w0
+    ; CHECK-NEXT: {{  $}}
+    ; CHECK-NEXT: DBG_VALUE %0:gpr32, $noreg, !7, !DIExpression(), debug-location !9
     %0:gpr(s32) = COPY $w0
     DBG_VALUE %0(s32), $noreg, !7, !DIExpression(), debug-location !9
 ...
diff --git a/llvm/test/CodeGen/AArch64/GlobalISel/select-hint.mir b/llvm/test/CodeGen/AArch64/GlobalISel/select-hint.mir
--- a/llvm/test/CodeGen/AArch64/GlobalISel/select-hint.mir
+++ b/llvm/test/CodeGen/AArch64/GlobalISel/select-hint.mir
@@ -16,7 +16,7 @@
     ; CHECK-LABEL: name: assert_zext_gpr
     ; CHECK: liveins: $w0, $w1
     ; CHECK-NEXT: {{  $}}
-    ; CHECK-NEXT: %copy:gpr32all = COPY $w0
+    ; CHECK-NEXT: %copy:gpr32 = COPY $w0
     ; CHECK-NEXT: $w1 = COPY %copy
     ; CHECK-NEXT: RET_ReallyLR implicit $w1
     %copy:gpr(s32) = COPY $w0
@@ -104,7 +104,7 @@
     ; CHECK-LABEL: name: assert_sext_gpr
     ; CHECK: liveins: $w0, $w1
     ; CHECK-NEXT: {{  $}}
-    ; CHECK-NEXT: %copy:gpr32all = COPY $w0
+    ; CHECK-NEXT: %copy:gpr32 = COPY $w0
     ; CHECK-NEXT: $w1 = COPY %copy
     ; CHECK-NEXT: RET_ReallyLR implicit $w1
     %copy:gpr(s32) = COPY $w0
diff --git a/llvm/test/DebugInfo/AArch64/debug-reg-bank.ll b/llvm/test/DebugInfo/AArch64/debug-reg-bank.ll
--- a/llvm/test/DebugInfo/AArch64/debug-reg-bank.ll
+++ b/llvm/test/DebugInfo/AArch64/debug-reg-bank.ll
@@ -6,7 +6,7 @@
   ; CHECK: bb.1.entry:
   ; CHECK-NEXT:   liveins: $w0
   ; CHECK-NEXT: {{  $}}
-  ; CHECK-NEXT:   DBG_VALUE %0:_, $noreg, !12, !DIExpression(), debug-location !19
+  ; CHECK-NEXT:   DBG_VALUE %0:gpr32, $noreg, !12, !DIExpression(), debug-location !19
   ; CHECK-NEXT:   RET_ReallyLR debug-location !20
 entry:
   call void @llvm.dbg.value(metadata i32 %n, i64 0, metadata !12, metadata !19), !dbg !20
diff --git a/llvm/test/DebugInfo/X86/debug-reg-bank.ll b/llvm/test/DebugInfo/X86/debug-reg-bank.ll
--- a/llvm/test/DebugInfo/X86/debug-reg-bank.ll
+++ b/llvm/test/DebugInfo/X86/debug-reg-bank.ll
@@ -6,7 +6,7 @@
   ; CHECK: bb.1.entry:
   ; CHECK-NEXT:   liveins: $edi
   ; CHECK-NEXT: {{  $}}
-  ; CHECK-NEXT:   DBG_VALUE %0:gpr, $noreg, !12, !DIExpression(), debug-location !19
+  ; CHECK-NEXT:   DBG_VALUE %0:gr32, $noreg, !12, !DIExpression(), debug-location !19
   ; CHECK-NEXT:   RET 0, debug-location !20
 entry:
   call void @llvm.dbg.value(metadata i32 %n, i64 0, metadata !12, metadata !19), !dbg !20