diff --git a/llvm/utils/TableGen/CodeGenRegisters.cpp b/llvm/utils/TableGen/CodeGenRegisters.cpp
--- a/llvm/utils/TableGen/CodeGenRegisters.cpp
+++ b/llvm/utils/TableGen/CodeGenRegisters.cpp
@@ -834,6 +834,12 @@
   VTs = Super.VTs;
   CopyCost = Super.CopyCost;
   Allocatable = Super.Allocatable;
+  if (!Allocatable) {
+    // Check for allocatable superclasses.
+    for (auto S = SuperClasses.rbegin();
+         S != SuperClasses.rend() && !Allocatable; ++S)
+      Allocatable |= (*S)->Allocatable;
+  }
   AltOrderSelect = Super.AltOrderSelect;
   AllocationPriority = Super.AllocationPriority;
   GeneratePressureSet |= Super.GeneratePressureSet;