diff --git a/llvm/include/llvm/CodeGen/RegAllocCommon.h b/llvm/include/llvm/CodeGen/RegAllocCommon.h
index 757ca8e112eec..943c9dd9e9bf5 100644
--- a/llvm/include/llvm/CodeGen/RegAllocCommon.h
+++ b/llvm/include/llvm/CodeGen/RegAllocCommon.h
@@ -10,22 +10,24 @@
 #define LLVM_CODEGEN_REGALLOCCOMMON_H
 
 #include <functional>
+#include <llvm/CodeGen/Register.h>
 
 namespace llvm {
 
-class TargetRegisterClass;
 class TargetRegisterInfo;
+class MachineRegisterInfo;
 
 typedef std::function<bool(const TargetRegisterInfo &TRI,
-                           const TargetRegisterClass &RC)> RegClassFilterFunc;
+                           const MachineRegisterInfo &MRI, const Register Reg)>
+    RegClassFilterFunc;
 
 /// Default register class filter function for register allocation. All virtual
 /// registers should be allocated.
 static inline bool allocateAllRegClasses(const TargetRegisterInfo &,
-                                         const TargetRegisterClass &) {
+                                         const MachineRegisterInfo &,
+                                         const Register) {
   return true;
 }
-
 }
 
 #endif // LLVM_CODEGEN_REGALLOCCOMMON_H
diff --git a/llvm/lib/CodeGen/RegAllocBase.cpp b/llvm/lib/CodeGen/RegAllocBase.cpp
index d0dec372f6896..a4645ed93029d 100644
--- a/llvm/lib/CodeGen/RegAllocBase.cpp
+++ b/llvm/lib/CodeGen/RegAllocBase.cpp
@@ -181,8 +181,7 @@ void RegAllocBase::enqueue(const LiveInterval *LI) {
   if (VRM->hasPhys(Reg))
     return;
 
-  const TargetRegisterClass &RC = *MRI->getRegClass(Reg);
-  if (ShouldAllocateClass(*TRI, RC)) {
+  if (ShouldAllocateClass(*TRI, *MRI, Reg)) {
     LLVM_DEBUG(dbgs() << "Enqueuing " << printReg(Reg, TRI) << '\n');
     enqueueImpl(LI);
   } else {
diff --git a/llvm/lib/CodeGen/RegAllocFast.cpp b/llvm/lib/CodeGen/RegAllocFast.cpp
index 6740e1f0edb4f..f6419daba6a2d 100644
--- a/llvm/lib/CodeGen/RegAllocFast.cpp
+++ b/llvm/lib/CodeGen/RegAllocFast.cpp
@@ -417,8 +417,7 @@ INITIALIZE_PASS(RegAllocFast, "regallocfast", "Fast Register Allocator", false,
 
 bool RegAllocFast::shouldAllocateRegister(const Register Reg) const {
   assert(Reg.isVirtual());
-  const TargetRegisterClass &RC = *MRI->getRegClass(Reg);
-  return ShouldAllocateClass(*TRI, RC);
+  return ShouldAllocateClass(*TRI, *MRI, Reg);
 }
 
 void RegAllocFast::setPhysRegState(MCPhysReg PhysReg, unsigned NewState) {
diff --git a/llvm/lib/CodeGen/RegAllocGreedy.cpp b/llvm/lib/CodeGen/RegAllocGreedy.cpp
index 348277224c7ae..c3d5984b46f51 100644
--- a/llvm/lib/CodeGen/RegAllocGreedy.cpp
+++ b/llvm/lib/CodeGen/RegAllocGreedy.cpp
@@ -2306,9 +2306,9 @@ void RAGreedy::tryHintRecoloring(const LiveInterval &VirtReg) {
     if (Reg.isPhysical())
       continue;
 
-    // This may be a skipped class
+    // This may be a skipped register
     if (!VRM->hasPhys(Reg)) {
-      assert(!ShouldAllocateClass(*TRI, *MRI->getRegClass(Reg)) &&
+      assert(!ShouldAllocateClass(*TRI, *MRI, Reg) &&
              "We have an unallocated variable which should have been handled");
       continue;
     }
@@ -2698,7 +2698,7 @@ bool RAGreedy::hasVirtRegAlloc() {
     const TargetRegisterClass *RC = MRI->getRegClass(Reg);
     if (!RC)
       continue;
-    if (ShouldAllocateClass(*TRI, *RC))
+    if (ShouldAllocateClass(*TRI, *MRI, Reg))
       return true;
   }
 
diff --git a/llvm/lib/Target/AMDGPU/AMDGPUTargetMachine.cpp b/llvm/lib/Target/AMDGPU/AMDGPUTargetMachine.cpp
index 305a6c8c3b926..3d6965fa9876c 100644
--- a/llvm/lib/Target/AMDGPU/AMDGPUTargetMachine.cpp
+++ b/llvm/lib/Target/AMDGPU/AMDGPUTargetMachine.cpp
@@ -81,16 +81,19 @@ class VGPRRegisterRegAlloc : public RegisterRegAllocBase<VGPRRegisterRegAlloc> {
 };
 
 static bool onlyAllocateSGPRs(const TargetRegisterInfo &TRI,
-                              const TargetRegisterClass &RC) {
-  return static_cast<const SIRegisterInfo &>(TRI).isSGPRClass(&RC);
+                              const MachineRegisterInfo &MRI,
+                              const Register Reg) {
+  const TargetRegisterClass *RC = MRI.getRegClass(Reg);
+  return static_cast<const SIRegisterInfo &>(TRI).isSGPRClass(RC);
 }
 
 static bool onlyAllocateVGPRs(const TargetRegisterInfo &TRI,
-                              const TargetRegisterClass &RC) {
-  return !static_cast<const SIRegisterInfo &>(TRI).isSGPRClass(&RC);
+                              const MachineRegisterInfo &MRI,
+                              const Register Reg) {
+  const TargetRegisterClass *RC = MRI.getRegClass(Reg);
+  return !static_cast<const SIRegisterInfo &>(TRI).isSGPRClass(RC);
 }
 
-
 /// -{sgpr|vgpr}-regalloc=... command line option.
 static FunctionPass *useDefaultRegisterAllocator() { return nullptr; }
 
diff --git a/llvm/lib/Target/RISCV/RISCVTargetMachine.cpp b/llvm/lib/Target/RISCV/RISCVTargetMachine.cpp
index 0876f46728a10..44a26c48c63e0 100644
--- a/llvm/lib/Target/RISCV/RISCVTargetMachine.cpp
+++ b/llvm/lib/Target/RISCV/RISCVTargetMachine.cpp
@@ -273,8 +273,10 @@ class RVVRegisterRegAlloc : public RegisterRegAllocBase<RVVRegisterRegAlloc> {
 };
 
 static bool onlyAllocateRVVReg(const TargetRegisterInfo &TRI,
-                               const TargetRegisterClass &RC) {
-  return RISCVRegisterInfo::isRVVRegClass(&RC);
+                               const MachineRegisterInfo &MRI,
+                               const Register Reg) {
+  const TargetRegisterClass *RC = MRI.getRegClass(Reg);
+  return RISCVRegisterInfo::isRVVRegClass(RC);
 }
 
 static FunctionPass *useDefaultRegisterAllocator() { return nullptr; }
diff --git a/llvm/lib/Target/X86/X86TargetMachine.cpp b/llvm/lib/Target/X86/X86TargetMachine.cpp
index 86b456019c4e5..eab537e8a5f8b 100644
--- a/llvm/lib/Target/X86/X86TargetMachine.cpp
+++ b/llvm/lib/Target/X86/X86TargetMachine.cpp
@@ -652,8 +652,10 @@ std::unique_ptr<CSEConfigBase> X86PassConfig::getCSEConfig() const {
 }
 
 static bool onlyAllocateTileRegisters(const TargetRegisterInfo &TRI,
-                                      const TargetRegisterClass &RC) {
-  return static_cast<const X86RegisterInfo &>(TRI).isTileRegisterClass(&RC);
+                                      const MachineRegisterInfo &MRI,
+                                      const Register Reg) {
+  const TargetRegisterClass *RC = MRI.getRegClass(Reg);
+  return static_cast<const X86RegisterInfo &>(TRI).isTileRegisterClass(RC);
 }
 
 bool X86PassConfig::addRegAssignAndRewriteOptimized() {