diff --git a/lib/CodeGen/MachineOperand.cpp b/lib/CodeGen/MachineOperand.cpp
index a116d8fe877..97d32a5d66a 100644
--- a/lib/CodeGen/MachineOperand.cpp
+++ b/lib/CodeGen/MachineOperand.cpp
@@ -461,7 +461,8 @@ static void printIRValueReference(raw_ostream &OS, const Value &V,
     printLLVMNameWithoutPrefix(OS, V.getName());
     return;
   }
-  MachineOperand::printIRSlotNumber(OS, MST.getLocalSlot(&V));
+  int Slot = MST.getCurrentFunction() ? MST.getLocalSlot(&V) : -1;
+  MachineOperand::printIRSlotNumber(OS, Slot);
 }
 
 static void printSyncScope(raw_ostream &OS, const LLVMContext &Context,
diff --git a/test/CodeGen/SystemZ/isel-debug.ll b/test/CodeGen/SystemZ/isel-debug.ll
new file mode 100644
index 00000000000..cf5370cbec6
--- /dev/null
+++ b/test/CodeGen/SystemZ/isel-debug.ll
@@ -0,0 +1,19 @@
+; RUN: llc < %s -mtriple=s390x-linux-gnu -debug-only=systemz-isel -o - 2>&1 | \
+; RUN:   FileCheck %s
+
+; REQUIRES: asserts
+;
+; Check that some debug output is printed without problems.
+; CHECK: SystemZAddressingMode
+; CHECK: Base
+; CHECK: Index
+; CHECK: Disp
+
+define void @fun(i64* %ptr) {
+entry:
+  %0 = bitcast i64* %ptr to i32**
+  %1 = load i32*, i32** %0, align 8
+  %xpv_pv = getelementptr inbounds i32, i32* %1
+  store i32 0, i32* %xpv_pv
+  ret void
+}