diff --git a/llvm/include/llvm/CodeGen/GlobalISel/LoadStoreOpt.h b/llvm/include/llvm/CodeGen/GlobalISel/LoadStoreOpt.h
--- a/llvm/include/llvm/CodeGen/GlobalISel/LoadStoreOpt.h
+++ b/llvm/include/llvm/CodeGen/GlobalISel/LoadStoreOpt.h
@@ -16,6 +16,7 @@
 
 #include "llvm/ADT/BitVector.h"
 #include "llvm/ADT/SmallPtrSet.h"
+#include "llvm/ADT/SmallSet.h"
 #include "llvm/ADT/SmallVector.h"
 #include "llvm/Analysis/AliasAnalysis.h"
 #include "llvm/CodeGen/GlobalISel/MachineIRBuilder.h"
diff --git a/llvm/include/llvm/CodeGen/MachineInstr.h b/llvm/include/llvm/CodeGen/MachineInstr.h
--- a/llvm/include/llvm/CodeGen/MachineInstr.h
+++ b/llvm/include/llvm/CodeGen/MachineInstr.h
@@ -17,7 +17,6 @@
 
 #include "llvm/ADT/DenseMapInfo.h"
 #include "llvm/ADT/PointerSumType.h"
-#include "llvm/ADT/SmallSet.h"
 #include "llvm/ADT/ilist.h"
 #include "llvm/ADT/ilist_node.h"
 #include "llvm/ADT/iterator_range.h"
@@ -568,15 +567,6 @@
     return *(debug_operands().begin() + Index);
   }
 
-  SmallSet<Register, 4> getUsedDebugRegs() const {
-    assert(isDebugValue() && "not a DBG_VALUE*");
-    SmallSet<Register, 4> UsedRegs;
-    for (const auto &MO : debug_operands())
-      if (MO.isReg() && MO.getReg())
-        UsedRegs.insert(MO.getReg());
-    return UsedRegs;
-  }
-
   /// Returns whether this debug value has at least one debug operand with the
   /// register \p Reg.
   bool hasDebugOperandForReg(Register Reg) const {
diff --git a/llvm/lib/CodeGen/CalcSpillWeights.cpp b/llvm/lib/CodeGen/CalcSpillWeights.cpp
--- a/llvm/lib/CodeGen/CalcSpillWeights.cpp
+++ b/llvm/lib/CodeGen/CalcSpillWeights.cpp
@@ -8,6 +8,7 @@
 
 #include "llvm/CodeGen/CalcSpillWeights.h"
 #include "llvm/ADT/SmallPtrSet.h"
+#include "llvm/ADT/SmallSet.h"
 #include "llvm/CodeGen/LiveInterval.h"
 #include "llvm/CodeGen/LiveIntervals.h"
 #include "llvm/CodeGen/MachineFunction.h"
diff --git a/llvm/lib/CodeGen/RegAllocFast.cpp b/llvm/lib/CodeGen/RegAllocFast.cpp
--- a/llvm/lib/CodeGen/RegAllocFast.cpp
+++ b/llvm/lib/CodeGen/RegAllocFast.cpp
@@ -1509,7 +1509,11 @@
 void RegAllocFast::handleDebugValue(MachineInstr &MI) {
   // Ignore DBG_VALUEs that aren't based on virtual registers. These are
   // mostly constants and frame indices.
-  for (Register Reg : MI.getUsedDebugRegs()) {
+  assert(MI.isDebugValue() && "not a DBG_VALUE*");
+  for (const auto &MO : MI.debug_operands()) {
+    if (!MO.isReg())
+      continue;
+    Register Reg = MO.getReg();
     if (!Reg.isVirtual())
       continue;
     if (!shouldAllocateRegister(Reg))
diff --git a/llvm/lib/Target/RISCV/RISCVOptWInstrs.cpp b/llvm/lib/Target/RISCV/RISCVOptWInstrs.cpp
--- a/llvm/lib/Target/RISCV/RISCVOptWInstrs.cpp
+++ b/llvm/lib/Target/RISCV/RISCVOptWInstrs.cpp
@@ -22,6 +22,7 @@
 #include "RISCV.h"
 #include "RISCVMachineFunctionInfo.h"
 #include "RISCVSubtarget.h"
+#include "llvm/ADT/SmallSet.h"
 #include "llvm/ADT/Statistic.h"
 #include "llvm/CodeGen/MachineFunctionPass.h"
 #include "llvm/CodeGen/TargetInstrInfo.h"
diff --git a/llvm/lib/Target/RISCV/RISCVRVVInitUndef.cpp b/llvm/lib/Target/RISCV/RISCVRVVInitUndef.cpp
--- a/llvm/lib/Target/RISCV/RISCVRVVInitUndef.cpp
+++ b/llvm/lib/Target/RISCV/RISCVRVVInitUndef.cpp
@@ -34,6 +34,7 @@
 
 #include "RISCV.h"
 #include "RISCVSubtarget.h"
+#include "llvm/ADT/SmallSet.h"
 #include "llvm/CodeGen/DetectDeadLanes.h"
 #include "llvm/CodeGen/MachineFunctionPass.h"
 using namespace llvm;
diff --git a/llvm/lib/Target/RISCV/RISCVRegisterInfo.cpp b/llvm/lib/Target/RISCV/RISCVRegisterInfo.cpp
--- a/llvm/lib/Target/RISCV/RISCVRegisterInfo.cpp
+++ b/llvm/lib/Target/RISCV/RISCVRegisterInfo.cpp
@@ -14,6 +14,7 @@
 #include "RISCV.h"
 #include "RISCVMachineFunctionInfo.h"
 #include "RISCVSubtarget.h"
+#include "llvm/ADT/SmallSet.h"
 #include "llvm/BinaryFormat/Dwarf.h"
 #include "llvm/CodeGen/MachineFrameInfo.h"
 #include "llvm/CodeGen/MachineFunction.h"
diff --git a/llvm/lib/Target/WebAssembly/WebAssemblyExceptionInfo.h b/llvm/lib/Target/WebAssembly/WebAssemblyExceptionInfo.h
--- a/llvm/lib/Target/WebAssembly/WebAssemblyExceptionInfo.h
+++ b/llvm/lib/Target/WebAssembly/WebAssemblyExceptionInfo.h
@@ -15,6 +15,7 @@
 #define LLVM_LIB_TARGET_WEBASSEMBLY_WEBASSEMBLYEXCEPTIONINFO_H
 
 #include "WebAssembly.h"
+#include "llvm/ADT/SmallPtrSet.h"
 #include "llvm/CodeGen/MachineFunctionPass.h"
 
 namespace llvm {
diff --git a/llvm/lib/Target/WebAssembly/WebAssemblyLowerEmscriptenEHSjLj.cpp b/llvm/lib/Target/WebAssembly/WebAssemblyLowerEmscriptenEHSjLj.cpp
--- a/llvm/lib/Target/WebAssembly/WebAssemblyLowerEmscriptenEHSjLj.cpp
+++ b/llvm/lib/Target/WebAssembly/WebAssemblyLowerEmscriptenEHSjLj.cpp
@@ -282,6 +282,7 @@
 #include "llvm/Transforms/Utils/Local.h"
 #include "llvm/Transforms/Utils/SSAUpdater.h"
 #include "llvm/Transforms/Utils/SSAUpdaterBulk.h"
+#include <set>
 
 using namespace llvm;
 
diff --git a/llvm/lib/Target/WebAssembly/WebAssemblyLowerRefTypesIntPtrConv.cpp b/llvm/lib/Target/WebAssembly/WebAssemblyLowerRefTypesIntPtrConv.cpp
--- a/llvm/lib/Target/WebAssembly/WebAssemblyLowerRefTypesIntPtrConv.cpp
+++ b/llvm/lib/Target/WebAssembly/WebAssemblyLowerRefTypesIntPtrConv.cpp
@@ -19,6 +19,7 @@
 #include "WebAssemblySubtarget.h"
 #include "llvm/IR/InstIterator.h"
 #include "llvm/Pass.h"
+#include <set>
 
 using namespace llvm;
 
diff --git a/llvm/lib/Target/X86/X86PreTileConfig.cpp b/llvm/lib/Target/X86/X86PreTileConfig.cpp
--- a/llvm/lib/Target/X86/X86PreTileConfig.cpp
+++ b/llvm/lib/Target/X86/X86PreTileConfig.cpp
@@ -28,6 +28,7 @@
 #include "X86MachineFunctionInfo.h"
 #include "X86RegisterInfo.h"
 #include "X86Subtarget.h"
+#include "llvm/ADT/SmallSet.h"
 #include "llvm/CodeGen/MachineFunctionPass.h"
 #include "llvm/CodeGen/MachineInstr.h"
 #include "llvm/CodeGen/MachineLoopInfo.h"