diff --git a/llvm/lib/CodeGen/GlobalISel/LegalizerHelper.cpp b/llvm/lib/CodeGen/GlobalISel/LegalizerHelper.cpp
index e4a5515..3870e66 100644
--- a/llvm/lib/CodeGen/GlobalISel/LegalizerHelper.cpp
+++ b/llvm/lib/CodeGen/GlobalISel/LegalizerHelper.cpp
@@ -596,6 +596,8 @@
                     LostDebugLocObserver &LocObserver, MachineInstr *MI) {
   auto &TLI = *MIRBuilder.getMF().getSubtarget().getTargetLowering();
   const char *Name = TLI.getLibcallName(Libcall);
+  if (!Name)
+    return LegalizerHelper::UnableToLegalize;
   const CallingConv::ID CC = TLI.getLibcallCallingConv(Libcall);
   return createLibcall(MIRBuilder, Name, Result, Args, CC, LocObserver, MI);
 }