diff --git a/include/llvm/CodeGen/TargetFrameLowering.h b/include/llvm/CodeGen/TargetFrameLowering.h
index 72edb27..2100a64 100644
--- a/include/llvm/CodeGen/TargetFrameLowering.h
+++ b/include/llvm/CodeGen/TargetFrameLowering.h
@@ -282,6 +282,11 @@
     return getFrameIndexReference(MF, FI, FrameReg);
   }
 
+  /// Returns the callee-saved registers as computed by determineCalleeSaves
+  /// in the BitVector \p SavedRegs.
+  virtual void getCalleeSaves(const MachineFunction &MF,
+                                  BitVector &SavedRegs) const;
+
   /// This method determines which of the registers reported by
   /// TargetRegisterInfo::getCalleeSavedRegs() should actually get saved.
   /// The default implementation checks populates the \p SavedRegs bitset with
@@ -289,6 +294,9 @@
   /// this function to save additional registers.
   /// This method also sets up the register scavenger ensuring there is a free
   /// register or a frameindex available.
+  /// This method should not be called by any passes outside of PEI, because
+  /// it may change state passed in by \p MF and \p RS. The preferred
+  /// interface outside PEI is getCalleeSaves.
   virtual void determineCalleeSaves(MachineFunction &MF, BitVector &SavedRegs,
                                     RegScavenger *RS = nullptr) const;
 
diff --git a/lib/CodeGen/LiveDebugValues.cpp b/lib/CodeGen/LiveDebugValues.cpp
index f1b237d..ca20b11 100644
--- a/lib/CodeGen/LiveDebugValues.cpp
+++ b/lib/CodeGen/LiveDebugValues.cpp
@@ -1439,8 +1439,7 @@
   TRI = MF.getSubtarget().getRegisterInfo();
   TII = MF.getSubtarget().getInstrInfo();
   TFI = MF.getSubtarget().getFrameLowering();
-  TFI->determineCalleeSaves(MF, CalleeSavedRegs,
-                            std::make_unique<RegScavenger>().get());
+  TFI->getCalleeSaves(MF, CalleeSavedRegs);
   LS.initialize(MF);
 
   bool Changed = ExtendRanges(MF);
diff --git a/lib/CodeGen/RegUsageInfoCollector.cpp b/lib/CodeGen/RegUsageInfoCollector.cpp
index 757ff0e..5a79ac4 100644
--- a/lib/CodeGen/RegUsageInfoCollector.cpp
+++ b/lib/CodeGen/RegUsageInfoCollector.cpp
@@ -56,7 +56,7 @@
 
   bool runOnMachineFunction(MachineFunction &MF) override;
 
-  // Call determineCalleeSaves and then also set the bits for subregs and
+  // Call getCalleeSaves and then also set the bits for subregs and
   // fully saved superregs.
   static void computeCalleeSavedRegs(BitVector &SavedRegs, MachineFunction &MF);
 
@@ -199,7 +199,7 @@
 
   // Target will return the set of registers that it saves/restores as needed.
   SavedRegs.clear();
-  TFI.determineCalleeSaves(MF, SavedRegs);
+  TFI.getCalleeSaves(MF, SavedRegs);
   if (SavedRegs.none())
     return;
 
diff --git a/lib/CodeGen/TargetFrameLoweringImpl.cpp b/lib/CodeGen/TargetFrameLoweringImpl.cpp
index 9eeacc2..bc59be8 100644
--- a/lib/CodeGen/TargetFrameLoweringImpl.cpp
+++ b/lib/CodeGen/TargetFrameLoweringImpl.cpp
@@ -60,6 +60,19 @@
   return MF.getFrameInfo().hasStackObjects();
 }
 
+void TargetFrameLowering::getCalleeSaves(const MachineFunction &MF,
+                                         BitVector &CalleeSaves) const {
+  const TargetRegisterInfo &TRI = *MF.getSubtarget().getRegisterInfo();
+  CalleeSaves.resize(TRI.getNumRegs());
+
+  const MachineFrameInfo &MFI = MF.getFrameInfo();
+  if (!MFI.isCalleeSavedInfoValid())
+    return;
+
+  for (const CalleeSavedInfo &Info : MFI.getCalleeSavedInfo())
+    CalleeSaves.set(Info.getReg());
+}
+
 void TargetFrameLowering::determineCalleeSaves(MachineFunction &MF,
                                                BitVector &SavedRegs,
                                                RegScavenger *RS) const {
diff --git a/lib/Target/AArch64/AArch64FrameLowering.cpp b/lib/Target/AArch64/AArch64FrameLowering.cpp
index 68e1e6a..042d8fd 100644
--- a/lib/Target/AArch64/AArch64FrameLowering.cpp
+++ b/lib/Target/AArch64/AArch64FrameLowering.cpp
@@ -1588,7 +1588,8 @@
   bool IsWin64 =
       Subtarget.isCallingConvWin64(MF.getFunction().getCallingConv());
   unsigned FixedObject = IsWin64 ? alignTo(AFI->getVarArgsGPRSize(), 16) : 0;
-  unsigned FPAdjust = isTargetDarwin(MF) ? 16 : AFI->getCalleeSavedStackSize();
+  unsigned FPAdjust = isTargetDarwin(MF)
+                        ? 16 : AFI->getCalleeSavedStackSize(MF.getFrameInfo());
   return {ObjectOffset + FixedObject + FPAdjust, MVT::i8};
 }
 
@@ -1630,7 +1631,7 @@
   int FPOffset = getFPOffset(MF, ObjectOffset).getBytes();
   int Offset = getStackOffset(MF, ObjectOffset).getBytes();
   bool isCSR =
-      !isFixed && ObjectOffset >= -((int)AFI->getCalleeSavedStackSize());
+      !isFixed && ObjectOffset >= -((int)AFI->getCalleeSavedStackSize(MFI));
 
   const StackOffset &SVEStackSize = getSVEStackSize(MF);
 
@@ -2304,6 +2305,10 @@
                << EstimatedStackSize + AlignedCSStackSize
                << " bytes.\n");
 
+  assert((!MFI.isCalleeSavedInfoValid() ||
+          AFI->getCalleeSavedStackSize() == AlignedCSStackSize) &&
+         "Should not invalidate callee saved info");
+
   // Round up to register pair alignment to avoid additional SP adjustment
   // instructions.
   AFI->setCalleeSavedStackSize(AlignedCSStackSize);
diff --git a/lib/Target/AArch64/AArch64MachineFunctionInfo.h b/lib/Target/AArch64/AArch64MachineFunctionInfo.h
index 0009fb7..3266186 100644
--- a/lib/Target/AArch64/AArch64MachineFunctionInfo.h
+++ b/lib/Target/AArch64/AArch64MachineFunctionInfo.h
@@ -55,6 +55,7 @@
 
   /// Amount of stack frame size used for saving callee-saved registers.
   unsigned CalleeSavedStackSize;
+  bool HasCalleeSavedStackSize = false;
 
   /// Number of TLS accesses using the special (combinable)
   /// _TLS_MODULE_BASE_ symbol.
@@ -167,8 +168,55 @@
   void setLocalStackSize(unsigned Size) { LocalStackSize = Size; }
   unsigned getLocalStackSize() const { return LocalStackSize; }
 
-  void setCalleeSavedStackSize(unsigned Size) { CalleeSavedStackSize = Size; }
-  unsigned getCalleeSavedStackSize() const { return CalleeSavedStackSize; }
+  void setCalleeSavedStackSize(unsigned Size) {
+    CalleeSavedStackSize = Size;
+    HasCalleeSavedStackSize = true;
+  }
+
+  // When CalleeSavedStackSize has not been set (for example when
+  // some MachineIR pass is run in isolation), then recalculate
+  // the CalleeSavedStackSize directly from the CalleeSavedInfo.
+  // Note: This information can only be recalculated after PEI
+  // has assigned offsets to the callee save objects.
+  unsigned getCalleeSavedStackSize(const MachineFrameInfo &MFI) const {
+    bool ValidateCalleeSavedStackSize = false;
+
+#ifndef NDEBUG
+    // Make sure the calculated size derived from the CalleeSavedInfo
+    // equals the cached size that was calculated elsewhere (e.g. in
+    // determineCalleeSaves).
+    ValidateCalleeSavedStackSize = HasCalleeSavedStackSize;
+#endif
+
+    if (!HasCalleeSavedStackSize || ValidateCalleeSavedStackSize) {
+      assert(MFI.isCalleeSavedInfoValid() && "CalleeSavedInfo not calculated");
+      if (MFI.getCalleeSavedInfo().empty())
+        return 0;
+
+      int64_t MinOffset = std::numeric_limits<int64_t>::max();
+      int64_t MaxOffset = std::numeric_limits<int64_t>::min();
+      for (const auto &Info : MFI.getCalleeSavedInfo()) {
+        int FrameIdx = Info.getFrameIdx();
+        int64_t Offset = MFI.getObjectOffset(FrameIdx);
+        int64_t ObjSize = MFI.getObjectSize(FrameIdx);
+        MinOffset = std::min<int64_t>(Offset, MinOffset);
+        MaxOffset = std::max<int64_t>(Offset + ObjSize, MaxOffset);
+      }
+
+      unsigned Size = alignTo(MaxOffset - MinOffset, 16);
+      assert((!HasCalleeSavedStackSize || getCalleeSavedStackSize() == Size) &&
+             "Invalid size calculated for callee saves");
+      return Size;
+    }
+
+    return getCalleeSavedStackSize();
+  }
+
+  unsigned getCalleeSavedStackSize() const {
+    assert(HasCalleeSavedStackSize &&
+           "CalleeSavedStackSize has not been calculated");
+    return CalleeSavedStackSize;
+  }
 
   void incNumLocalDynamicTLSAccesses() { ++NumLocalDynamicTLSAccesses; }
   unsigned getNumLocalDynamicTLSAccesses() const {
diff --git a/lib/Target/ARM/ARMFrameLowering.cpp b/lib/Target/ARM/ARMFrameLowering.cpp
index 01ae930..5428bd6 100644
--- a/lib/Target/ARM/ARMFrameLowering.cpp
+++ b/lib/Target/ARM/ARMFrameLowering.cpp
@@ -2128,10 +2128,16 @@
     AFI->setLRIsSpilledForFarJump(true);
   }
   AFI->setLRIsSpilled(SavedRegs.test(ARM::LR));
+}
+
+void ARMFrameLowering::getCalleeSaves(const MachineFunction &MF,
+                                      BitVector &SavedRegs) const {
+  TargetFrameLowering::getCalleeSaves(MF, SavedRegs);
 
   // If we have the "returned" parameter attribute which guarantees that we
   // return the value which was passed in r0 unmodified (e.g. C++ 'structors),
   // record that fact for IPRA.
+  const ARMFunctionInfo *AFI = MF.getInfo<ARMFunctionInfo>();
   if (AFI->getPreservesR0())
     SavedRegs.set(ARM::R0);
 }
diff --git a/lib/Target/ARM/ARMFrameLowering.h b/lib/Target/ARM/ARMFrameLowering.h
index 6d8aee5..0462b01 100644
--- a/lib/Target/ARM/ARMFrameLowering.h
+++ b/lib/Target/ARM/ARMFrameLowering.h
@@ -53,6 +53,8 @@
   int ResolveFrameIndexReference(const MachineFunction &MF, int FI,
                                  unsigned &FrameReg, int SPAdj) const;
 
+  void getCalleeSaves(const MachineFunction &MF,
+                      BitVector &SavedRegs) const override;
   void determineCalleeSaves(MachineFunction &MF, BitVector &SavedRegs,
                             RegScavenger *RS) const override;
 
diff --git a/test/CodeGen/AArch64/wrong-callee-save-size-after-livedebugvariables.mir b/test/CodeGen/AArch64/wrong-callee-save-size-after-livedebugvariables.mir
new file mode 100644
index 0000000..231de4e
--- /dev/null
+++ b/test/CodeGen/AArch64/wrong-callee-save-size-after-livedebugvariables.mir
@@ -0,0 +1,92 @@
+# RUN: llc -start-before=prologepilog -filetype=obj -o %t %s
+# RUN: llvm-dwarfdump --name=obj1 %t | FileCheck %s --check-prefix=CHECKDWARF1
+# RUN: llvm-dwarfdump --name=obj2 %t | FileCheck %s --check-prefix=CHECKDWARF2
+# RUN: llvm-objdump --disassemble %t | FileCheck %s --check-prefix=CHECKASM
+#
+# Test that the location for obj1 and obj2 in the debug information is
+# the same as the location used by load instructions.
+#
+# CHECKDWARF1: DW_AT_location    (DW_OP_fbreg -1)
+# CHECKDWARF2: DW_AT_location    (DW_OP_fbreg -2)
+# CHECKASM: ldurb   w0, [x29, #-1]
+# CHECKASM: ldurb   w1, [x29, #-2]
+--- |
+  ; ModuleID = 'wrong-callee-save-size-after-livedebugvariables.c'
+  source_filename = "wrong-callee-save-size-after-livedebugvariables.c"
+  target datalayout = "e-m:e-i8:8:32-i16:16:32-i64:64-i128:128-n32:64-S128"
+  target triple = "aarch64-unknown-linux-gnu"
+
+  ; Function Attrs: noinline nounwind optnone
+  define dso_local i8 @foo() #0 !dbg !7 {
+  entry:
+    %obj1 = alloca i8, align 1
+    %obj2 = alloca i8, align 1
+    %obj3 = alloca [238 x i8], align 1
+    ret i8 undef, !dbg !24
+  }
+
+  declare dso_local i8 @bar(i8, i8, i8*) #0
+
+  attributes #0 = { noinline nounwind optnone "frame-pointer"="all" }
+
+  !llvm.dbg.cu = !{!0}
+  !llvm.module.flags = !{!3, !4, !5}
+  !llvm.ident = !{!6}
+
+  !0 = distinct !DICompileUnit(language: DW_LANG_C99, file: !1, producer: "clang version 10.0.0", isOptimized: false, runtimeVersion: 0, emissionKind: FullDebug, enums: !2, nameTableKind: None)
+  !1 = !DIFile(filename: "wrong-callee-save-size-after-livedebugvariables.c", directory: "")
+  !2 = !{}
+  !3 = !{i32 2, !"Dwarf Version", i32 4}
+  !4 = !{i32 2, !"Debug Info Version", i32 3}
+  !5 = !{i32 1, !"wchar_size", i32 4}
+  !6 = !{!"clang version 10.0.0"}
+  !7 = distinct !DISubprogram(name: "foo", scope: !1, file: !1, line: 3, type: !8, scopeLine: 3, flags: DIFlagPrototyped, spFlags: DISPFlagDefinition, unit: !0, retainedNodes: !2)
+  !8 = !DISubroutineType(types: !9)
+  !9 = !{!10}
+  !10 = !DIBasicType(name: "char", size: 8, encoding: DW_ATE_unsigned_char)
+  !11 = !DILocalVariable(name: "obj1", scope: !7, file: !1, line: 4, type: !10)
+  !12 = !DILocation(line: 4, column: 8, scope: !7)
+  !13 = !DILocalVariable(name: "obj2", scope: !7, file: !1, line: 5, type: !10)
+  !14 = !DILocation(line: 5, column: 8, scope: !7)
+  !15 = !DILocalVariable(name: "obj3", scope: !7, file: !1, line: 6, type: !16)
+  !16 = !DICompositeType(tag: DW_TAG_array_type, baseType: !10, size: 1904, elements: !17)
+  !17 = !{!18}
+  !18 = !DISubrange(count: 238)
+  !19 = !DILocation(line: 6, column: 8, scope: !7)
+  !20 = !DILocation(line: 7, column: 14, scope: !7)
+  !21 = !DILocation(line: 7, column: 20, scope: !7)
+  !22 = !DILocation(line: 7, column: 27, scope: !7)
+  !23 = !DILocation(line: 7, column: 10, scope: !7)
+  !24 = !DILocation(line: 7, column: 3, scope: !7)
+
+...
+---
+name:            foo
+tracksRegLiveness: true
+frameInfo:
+  hasCalls:        true
+fixedStack:      []
+stack:
+  - { id: 0, name: obj1, type: default, offset: 0, size: 1, alignment: 1,
+      stack-id: default, callee-saved-register: '', callee-saved-restored: true,
+      local-offset: -1, debug-info-variable: '!11', debug-info-expression: '!DIExpression()',
+      debug-info-location: '!12' }
+  - { id: 1, name: obj2, type: default, offset: 0, size: 1, alignment: 1,
+      stack-id: default, callee-saved-register: '', callee-saved-restored: true,
+      local-offset: -2, debug-info-variable: '!13', debug-info-expression: '!DIExpression()',
+      debug-info-location: '!14' }
+  - { id: 2, name: obj3, type: default, offset: 0, size: 238, alignment: 1,
+      stack-id: default, callee-saved-register: '', callee-saved-restored: true,
+      local-offset: -240, debug-info-variable: '!15', debug-info-expression: '!DIExpression()',
+      debug-info-location: '!19' }
+body:             |
+  bb.1.entry:
+    renamable $x2 = ADDXri %stack.2.obj3, 0, 0
+    renamable $w0 = LDRBBui %stack.0.obj1, 0, debug-location !20 :: (load 1 from %ir.obj1)
+    renamable $w1 = LDRBBui %stack.1.obj2, 0, debug-location !21 :: (load 1 from %ir.obj2)
+    ADJCALLSTACKDOWN 0, 0, implicit-def $sp, implicit $sp, debug-location !23
+    BL @bar, csr_aarch64_aapcs, implicit-def $lr, implicit $sp, implicit killed $w0, implicit killed $w1, implicit killed $x2, implicit-def $w0, debug-location !23
+    ADJCALLSTACKUP 0, 0, implicit-def $sp, implicit $sp, debug-location !23
+    RET_ReallyLR implicit killed $w0, debug-location !24
+
+...
diff --git a/test/DebugInfo/MIR/X86/live-debug-values-reg-copy.mir b/test/DebugInfo/MIR/X86/live-debug-values-reg-copy.mir
index ba748b9..3abde77 100644
--- a/test/DebugInfo/MIR/X86/live-debug-values-reg-copy.mir
+++ b/test/DebugInfo/MIR/X86/live-debug-values-reg-copy.mir
@@ -1,4 +1,4 @@
-# RUN: llc -run-pass=livedebugvalues %s -o - | FileCheck %s
+# RUN: llc -start-before=prologepilog -stop-after=livedebugvalues %s -o - | FileCheck %s
 #
 # This test tests tracking variables value transferring from one register to another.
 # This example is altered additionally in order to test transferring from one float register