Index: llvm/lib/CodeGen/CFIInstrInserter.cpp
===================================================================
--- llvm/lib/CodeGen/CFIInstrInserter.cpp
+++ llvm/lib/CodeGen/CFIInstrInserter.cpp
@@ -18,6 +18,7 @@
 //===----------------------------------------------------------------------===//
 
 #include "llvm/ADT/DepthFirstIterator.h"
+#include "llvm/ADT/SetOperations.h"
 #include "llvm/CodeGen/MachineFunctionPass.h"
 #include "llvm/CodeGen/MachineInstrBuilder.h"
 #include "llvm/CodeGen/MachineModuleInfo.h"
@@ -76,6 +77,10 @@
     unsigned IncomingCFARegister = 0;
     /// Value of cfa register valid at basic block exit.
     unsigned OutgoingCFARegister = 0;
+    /// Set of callee saved registers saved at basic block entry.
+    std::set<unsigned> IncomingCSRSaved;
+    /// Set of callee saved registers saved at basic block exit.
+    std::set<unsigned> OutgoingCSRSaved;
     /// If in/out cfa offset and register values for this block have already
     /// been set or not.
     bool Processed = false;
@@ -161,6 +166,7 @@
   unsigned SetRegister = MBBInfo.IncomingCFARegister;
   const std::vector<MCCFIInstruction> &Instrs =
       MBBInfo.MBB->getParent()->getFrameInstructions();
+  SmallVector<unsigned, 8> CSRSaved, CSRRestored;
 
   // Determine cfa offset and register set by the block.
   for (MachineInstr &MI : *MBBInfo.MBB) {
@@ -181,6 +187,15 @@
         SetRegister = CFI.getRegister();
         SetOffset = CFI.getOffset();
         break;
+      case MCCFIInstruction::OpOffset:
+      case MCCFIInstruction::OpRegister:
+      case MCCFIInstruction::OpRelOffset:
+        CSRSaved.push_back(CFI.getRegister());
+        break;
+      case MCCFIInstruction::OpRestore:
+      case MCCFIInstruction::OpUndefined:
+        CSRRestored.push_back(CFI.getRegister());
+        break;
       case MCCFIInstruction::OpRememberState:
         // TODO: Add support for handling cfi_remember_state.
 #ifndef NDEBUG
@@ -199,12 +214,7 @@
         break;
       // Other CFI directives do not affect CFA value.
       case MCCFIInstruction::OpSameValue:
-      case MCCFIInstruction::OpOffset:
-      case MCCFIInstruction::OpRelOffset:
       case MCCFIInstruction::OpEscape:
-      case MCCFIInstruction::OpRestore:
-      case MCCFIInstruction::OpUndefined:
-      case MCCFIInstruction::OpRegister:
       case MCCFIInstruction::OpWindowSave:
       case MCCFIInstruction::OpNegateRAState:
       case MCCFIInstruction::OpGnuArgsSize:
@@ -218,6 +228,13 @@
   // Update outgoing CFA info.
   MBBInfo.OutgoingCFAOffset = SetOffset;
   MBBInfo.OutgoingCFARegister = SetRegister;
+  // Update outgoing CSR info.
+
+  MBBInfo.OutgoingCSRSaved = MBBInfo.IncomingCSRSaved;
+  llvm::for_each(CSRSaved,
+                 [&](auto reg) { MBBInfo.OutgoingCSRSaved.insert(reg); });
+  llvm::for_each(CSRRestored,
+                 [&](auto reg) { MBBInfo.OutgoingCSRSaved.erase(reg); });
 }
 
 void CFIInstrInserter::updateSuccCFAInfo(MBBCFAInfo &MBBInfo) {
@@ -236,6 +253,7 @@
       if (!SuccInfo.Processed) {
         SuccInfo.IncomingCFAOffset = CurrentInfo.OutgoingCFAOffset;
         SuccInfo.IncomingCFARegister = CurrentInfo.OutgoingCFARegister;
+        SuccInfo.IncomingCSRSaved = CurrentInfo.OutgoingCSRSaved;
         Stack.push_back(Succ);
       }
     }
@@ -287,6 +305,15 @@
           .addCFIIndex(CFIIndex);
       InsertedCFIInstr = true;
     }
+    auto DiffResult =
+        set_difference(PrevMBBInfo->OutgoingCSRSaved, MBBInfo.IncomingCSRSaved);
+    for (unsigned Reg : DiffResult) {
+      unsigned CFIIndex =
+          MF.addFrameInst(MCCFIInstruction::createRestore(nullptr, Reg));
+      BuildMI(*MBBInfo.MBB, MBBI, DL, TII->get(TargetOpcode::CFI_INSTRUCTION))
+          .addCFIIndex(CFIIndex);
+      InsertedCFIInstr = true;
+    }
     PrevMBBInfo = &MBBInfo;
   }
   return InsertedCFIInstr;
Index: llvm/test/CodeGen/X86/cfi-inserter-callee-save-register.mir
===================================================================
--- /dev/null
+++ llvm/test/CodeGen/X86/cfi-inserter-callee-save-register.mir
@@ -0,0 +1,80 @@
+# RUN: llc -o - %s -mtriple=x86_64-- -verify-cfiinstrs \
+# RUN:     -run-pass=cfi-instr-inserter 2>&1 | FileCheck %s
+# Test that CFI inserter inserts .cfi_restore properly for
+# callee saved registers.
+--- |
+  define void @_Z3foobPl(i64* nocapture readonly %a) {
+  entry:
+    %arrayidx2 = getelementptr inbounds i64, i64* %a, i64 1
+    %arrayidx3 = getelementptr inbounds i64, i64* %a, i64 2
+    br label %if.then
+  if.then:
+    br label %return
+  return:
+      ret void
+  }
+  declare dso_local void @_Z3goov() local_unnamed_addr #1
+...
+---
+# CHECK:      bb.3.return:
+# CHECK:      CFI_INSTRUCTION restore $rbx
+# CHECK-NEXT: CFI_INSTRUCTION restore $rbp
+name:            _Z3foobPl
+alignment:       16
+tracksRegLiveness: true
+liveins:
+  - { reg: '$edi' }
+  - { reg: '$rsi' }
+frameInfo:
+  stackSize:       24
+  offsetAdjustment: -24
+  maxAlignment:    1
+  adjustsStack:    true
+  hasCalls:        true
+  maxCallFrameSize: 0
+  cvBytesOfCalleeSavedRegisters: 8
+fixedStack:
+  - { id: 0, type: spill-slot, offset: -24, size: 8, alignment: 8, callee-saved-register: '$rbx' }
+  - { id: 1, type: spill-slot, offset: -16, size: 8, alignment: 16 }
+machineFunctionInfo: {}
+body:             |
+  bb.0.entry:
+    successors: %bb.2(0x7fef9fcb), %bb.1(0x00106035)
+    liveins: $edi, $rsi, $rbx
+
+    TEST8rr renamable $dil, renamable $dil, implicit-def $eflags, implicit killed $edi
+    JCC_1 %bb.2, 5, implicit killed $eflags
+
+  bb.1:
+    liveins: $rbx
+
+    renamable $eax = MOV32r0 implicit-def dead $eflags, implicit-def $rax
+    JMP_1 %bb.3
+
+  bb.2.if.then:
+    liveins: $rsi:0x0000000D, $rbx
+
+    frame-setup PUSH64r killed $rbp, implicit-def $rsp, implicit $rsp
+    CFI_INSTRUCTION def_cfa_offset 16
+    CFI_INSTRUCTION offset $rbp, -16
+    $rbp = frame-setup MOV64rr $rsp
+    CFI_INSTRUCTION def_cfa_register $rbp
+    frame-setup PUSH64r killed $rbx, implicit-def $rsp, implicit $rsp
+    frame-setup PUSH64r undef $rax, implicit-def $rsp, implicit $rsp
+    CFI_INSTRUCTION offset $rbx, -24
+    renamable $rbx = COPY $rsi
+    CALL64pcrel32 @_Z3goov, csr_64, implicit $rsp, implicit $ssp, implicit-def $rsp, implicit-def $ssp
+    renamable $rax = MOV64rm renamable $rbx, 1, $noreg, 8, $noreg :: (load 8 from %ir.arrayidx2)
+    renamable $rax = nsw ADD64rm killed renamable $rax, renamable $rbx, 1, $noreg, 0, $noreg, implicit-def dead $eflags :: (load 8 from %ir.a)
+    renamable $rax = nsw ADD64rm killed renamable $rax, killed renamable $rbx, 1, $noreg, 16, $noreg, implicit-def dead $eflags :: (load 8 from %ir.arrayidx3)
+    $rsp = frame-destroy ADD64ri8 $rsp, 8, implicit-def dead $eflags
+    $rbx = frame-destroy POP64r implicit-def $rsp, implicit $rsp
+    $rbp = frame-destroy POP64r implicit-def $rsp, implicit $rsp
+    CFI_INSTRUCTION def_cfa $rsp, 8
+
+  bb.3.return:
+    liveins: $rax, $rbx
+
+    RET 0, $rax
+
+...