1 files changed, 18 insertions, 0 deletions
diff --git a/llvm/lib/CodeGen/MachineRegisterInfo.cpp b/llvm/lib/CodeGen/MachineRegisterInfo.cpp
index 9a92ee279cd..be06053f004 100644
--- a/llvm/lib/CodeGen/MachineRegisterInfo.cpp
+++ b/llvm/lib/CodeGen/MachineRegisterInfo.cpp
@@ -601,3 +601,21 @@ void MachineRegisterInfo::setCalleeSavedRegs(ArrayRef<MCPhysReg> CSRs) {
   UpdatedCSRs.push_back(0);
   IsUpdatedCSRsInitialized = true;
 }
+
+bool MachineRegisterInfo::isReservedRegUnit(unsigned Unit) const {
+  const TargetRegisterInfo *TRI = getTargetRegisterInfo();
+  for (MCRegUnitRootIterator Root(Unit, TRI); Root.isValid(); ++Root) {
+    bool IsRootReserved = true;
+    for (MCSuperRegIterator Super(*Root, TRI, /*IncludeSelf=*/true);
+         Super.isValid(); ++Super) {
+      unsigned Reg = *Super;
+      if (!isReserved(Reg)) {
+        IsRootReserved = false;
+        break;
+      }
+    }
+    if (IsRootReserved)
+      return true;
+  }
+  return false;
+}