Index: llvm/lib/Target/SystemZ/SystemZFrameLowering.cpp
===================================================================
--- llvm/lib/Target/SystemZ/SystemZFrameLowering.cpp
+++ llvm/lib/Target/SystemZ/SystemZFrameLowering.cpp
@@ -63,12 +63,13 @@
 }
 
 static bool usePackedStack(MachineFunction &MF) {
-  bool HasPackedStackAttr = MF.getFunction().hasFnAttribute("packed-stack");
+  bool PackedStack =
+    MF.getFunction().getFnAttribute("packed-stack").getValueAsString() == "true";
   bool IsVarArg = MF.getFunction().isVarArg();
   bool CallConv = MF.getFunction().getCallingConv() != CallingConv::GHC;
   bool BackChain = MF.getFunction().hasFnAttribute("backchain");
   bool FramAddressTaken = MF.getFrameInfo().isFrameAddressTaken();
-  return HasPackedStackAttr && !IsVarArg && CallConv && !BackChain &&
+  return PackedStack && !IsVarArg && CallConv && !BackChain &&
          !FramAddressTaken;
 }
 
Index: llvm/test/CodeGen/SystemZ/frame-22.ll
===================================================================
--- llvm/test/CodeGen/SystemZ/frame-22.ll
+++ llvm/test/CodeGen/SystemZ/frame-22.ll
@@ -84,4 +84,25 @@
   ret i64 %C
 }
 
+; Test that a packed-stack function attribute of "false" gets the default layout.
+define void @f5() #1 {
+; CHECK-LABEL: f5:
+; CHECK: stmg %r12, %r15, 96(%r15)
+; CHECK-NEXT: .cfi_offset %r12, -64
+; CHECK-NEXT: .cfi_offset %r15, -40
+; CHECK-NEXT: aghi %r15, -8
+; CHECK-NEXT: .cfi_def_cfa_offset 168
+; CHECK-NEXT: std %f8, 0(%r15)          # 8-byte Folded Spill
+; CHECK-NEXT: .cfi_offset %f8, -168
+; CHECK-NEXT: #APP
+; CHECK-NEXT: #NO_APP
+; CHECK-NEXT: ld %f8, 0(%r15)          # 8-byte Folded Reload
+; CHECK-NEXT: lmg %r12, %r15, 104(%r15)
+; CHECK-NEXT: br %r14
+  call void asm sideeffect "", "~{f8},~{r12}"() nounwind
+  ret void
+}
+
+
 attributes #0 = { "packed-stack"="true" }
+attributes #1 = { "packed-stack"="false" }