diff --git a/llvm/include/llvm/MC/MCRegisterInfo.h b/llvm/include/llvm/MC/MCRegisterInfo.h
--- a/llvm/include/llvm/MC/MCRegisterInfo.h
+++ b/llvm/include/llvm/MC/MCRegisterInfo.h
@@ -39,6 +39,7 @@
   const uint16_t RegsSize;
   const uint16_t RegSetSize;
   const uint16_t ID;
+  const uint16_t RegSizeInBits;
   const int8_t CopyCost;
   const bool Allocatable;
 
@@ -78,6 +79,12 @@
     return contains(Reg1) && contains(Reg2);
   }
 
+  /// Return the size of the physical register in bits if we are able to
+  /// determine it. This always returns zero for registers of targets that use
+  /// HW modes, as we need more information to determine the size of registers
+  /// in such cases. Use TargetRegisterInfo to cover them.
+  unsigned getSizeInBits() const { return RegSizeInBits; }
+
   /// getCopyCost - Return the cost of copying a value between two registers in
   /// this class. A negative number means the register class is very expensive
   /// to copy e.g. status flag register classes.
diff --git a/llvm/utils/TableGen/RegisterInfoEmitter.cpp b/llvm/utils/TableGen/RegisterInfoEmitter.cpp
--- a/llvm/utils/TableGen/RegisterInfoEmitter.cpp
+++ b/llvm/utils/TableGen/RegisterInfoEmitter.cpp
@@ -1084,12 +1084,15 @@
 
   for (const auto &RC : RegisterClasses) {
     assert(isInt<8>(RC.CopyCost) && "Copy cost too large.");
+    uint32_t RegSize = 0;
+    if (RC.RSI.isSimple())
+      RegSize = RC.RSI.getSimple().RegSize;
     OS << "  { " << RC.getName() << ", " << RC.getName() << "Bits, "
-       << RegClassStrings.get(RC.getName()) << ", "
-       << RC.getOrder().size() << ", sizeof(" << RC.getName() << "Bits), "
-       << RC.getQualifiedName() + "RegClassID" << ", "
-       << RC.CopyCost << ", "
-       << ( RC.Allocatable ? "true" : "false" ) << " },\n";
+       << RegClassStrings.get(RC.getName()) << ", " << RC.getOrder().size()
+       << ", sizeof(" << RC.getName() << "Bits), "
+       << RC.getQualifiedName() + "RegClassID"
+       << ", " << RegSize << ", " << RC.CopyCost << ", "
+       << (RC.Allocatable ? "true" : "false") << " },\n";
   }
 
   OS << "};\n\n";