diff --git a/llvm/lib/Target/SystemZ/SystemZISelLowering.cpp b/llvm/lib/Target/SystemZ/SystemZISelLowering.cpp
index 3dabc5ef540cfb..a7fdc3bc40fda0 100644
--- a/llvm/lib/Target/SystemZ/SystemZISelLowering.cpp
+++ b/llvm/lib/Target/SystemZ/SystemZISelLowering.cpp
@@ -1925,11 +1925,7 @@ SystemZTargetLowering::LowerCall(CallLoweringInfo &CLI,
     IsTailCall = false;
 
   // Integer args <=32 bits should have an extension attribute.
-  bool IsInternal = false;
-  if (auto *G = dyn_cast<GlobalAddressSDNode>(Callee))
-    if (const Function *Fn = dyn_cast<Function>(G->getGlobal()))
-      IsInternal = isFullyInternal(Fn);
-  verifyNarrowIntegerArgs(Outs, IsInternal);
+  verifyNarrowIntegerArgs_Call(Outs, &MF.getFunction(), Callee);
 
   // Analyze the operands of the call, assigning locations to each operand.
   SmallVector<CCValAssign, 16> ArgLocs;
@@ -2192,7 +2188,7 @@ SystemZTargetLowering::LowerReturn(SDValue Chain, CallingConv::ID CallConv,
   MachineFunction &MF = DAG.getMachineFunction();
 
   // Integer args <=32 bits should have an extension attribute.
-  verifyNarrowIntegerArgs(Outs, isFullyInternal(&MF.getFunction()));
+  verifyNarrowIntegerArgs_Ret(Outs, &MF.getFunction());
 
   // Assign locations to each returned value.
   SmallVector<CCValAssign, 16> RetLocs;
@@ -9834,23 +9830,74 @@ bool SystemZTargetLowering::isFullyInternal(const Function *Fn) const {
   return true;
 }
 
-// Verify that narrow integer arguments are extended as required by the ABI.
+static void printFunctionArgExts(const Function *F, raw_fd_ostream &OS) {
+  FunctionType *FT = F->getFunctionType();
+  const AttributeList &Attrs = F->getAttributes();
+  if (Attrs.hasRetAttrs())
+    OS << Attrs.getAsString(AttributeList::ReturnIndex) << " ";
+  OS << *F->getReturnType() << " @" << F->getName() << "(";
+  for (unsigned I = 0, E = FT->getNumParams(); I != E; ++I) {
+    if (I)
+      OS << ", ";
+    OS << *FT->getParamType(I);
+    AttributeSet ArgAttrs = Attrs.getParamAttrs(I);
+    for (auto A : {Attribute::SExt, Attribute::ZExt, Attribute::NoExt})
+      if (ArgAttrs.hasAttribute(A))
+        OS << " " << Attribute::getNameFromAttrKind(A);
+  }
+  OS << ")\n";
+}
+
 void SystemZTargetLowering::
+verifyNarrowIntegerArgs_Call(const SmallVectorImpl<ISD::OutputArg> &Outs,
+                             const Function *F, SDValue Callee) const {
+  bool IsInternal = false;
+  const Function *CalleeFn = nullptr;
+  if (auto *G = dyn_cast<GlobalAddressSDNode>(Callee))
+    if (CalleeFn = dyn_cast<Function>(G->getGlobal()))
+      IsInternal = isFullyInternal(CalleeFn);
+  if (!verifyNarrowIntegerArgs(Outs, IsInternal)) {
+    errs() << "ERROR: Missing extension attribute of passed "
+           << "value in call to function:\n" << "Callee:  ";
+    if (CalleeFn != nullptr)
+      printFunctionArgExts(CalleeFn, errs());
+    else
+      errs() << "-";
+    errs() << "Caller:  ";
+    printFunctionArgExts(F, errs());
+    llvm_unreachable("");
+  }
+}
+
+void SystemZTargetLowering::
+verifyNarrowIntegerArgs_Ret(const SmallVectorImpl<ISD::OutputArg> &Outs,
+                            const Function *F) const {
+  if (!verifyNarrowIntegerArgs(Outs, isFullyInternal(F))) {
+    errs() << "ERROR: Missing extension attribute of returned "
+           << "value from function:\n";
+    printFunctionArgExts(F, errs());
+    llvm_unreachable("");
+  }
+}
+
+// Verify that narrow integer arguments are extended as required by the ABI.
+// Return false if an error is found.
+bool SystemZTargetLowering::
 verifyNarrowIntegerArgs(const SmallVectorImpl<ISD::OutputArg> &Outs,
                         bool IsInternal) const {
   if (IsInternal || !Subtarget.isTargetELF())
-    return;
+    return true;
 
   // Temporarily only do the check when explicitly requested, until it can be
   // enabled by default.
   if (!EnableIntArgExtCheck)
-    return;
+    return true;
 
   if (EnableIntArgExtCheck.getNumOccurrences()) {
     if (!EnableIntArgExtCheck)
-      return;
+      return true;
   } else if (!getTargetMachine().Options.VerifyArgABICompliance)
-    return;
+    return true;
 
   for (unsigned i = 0; i < Outs.size(); ++i) {
     MVT VT = Outs[i].VT;
@@ -9858,10 +9905,11 @@ verifyNarrowIntegerArgs(const SmallVectorImpl<ISD::OutputArg> &Outs,
     if (VT.isInteger()) {
       assert((VT == MVT::i32 || VT.getSizeInBits() >= 64) &&
              "Unexpected integer argument VT.");
-      assert((VT != MVT::i32 ||
-              (Flags.isSExt() || Flags.isZExt() || Flags.isNoExt())) &&
-             "Narrow integer argument must have a valid extension type.");
-      (void)Flags;
+      if (VT == MVT::i32 &&
+          !Flags.isSExt() && !Flags.isZExt() && !Flags.isNoExt())
+        return false;
     }
   }
+
+  return true;
 }
diff --git a/llvm/lib/Target/SystemZ/SystemZISelLowering.h b/llvm/lib/Target/SystemZ/SystemZISelLowering.h
index 8c528897182d17..2b065245c16f20 100644
--- a/llvm/lib/Target/SystemZ/SystemZISelLowering.h
+++ b/llvm/lib/Target/SystemZ/SystemZISelLowering.h
@@ -806,7 +806,11 @@ class SystemZTargetLowering : public TargetLowering {
   const TargetRegisterClass *getRepRegClassFor(MVT VT) const override;
 
   bool isFullyInternal(const Function *Fn) const;
-  void verifyNarrowIntegerArgs(const SmallVectorImpl<ISD::OutputArg> &Outs,
+  void verifyNarrowIntegerArgs_Call(const SmallVectorImpl<ISD::OutputArg> &Outs,
+                                    const Function *F, SDValue Callee) const;
+  void verifyNarrowIntegerArgs_Ret(const SmallVectorImpl<ISD::OutputArg> &Outs,
+                                   const Function *F) const;
+  bool verifyNarrowIntegerArgs(const SmallVectorImpl<ISD::OutputArg> &Outs,
                                bool IsInternal) const;
 };
 
diff --git a/llvm/test/CodeGen/SystemZ/args-15.ll b/llvm/test/CodeGen/SystemZ/args-15.ll
index c810aeb8c46c5d..64217a2a29a6f9 100644
--- a/llvm/test/CodeGen/SystemZ/args-15.ll
+++ b/llvm/test/CodeGen/SystemZ/args-15.ll
@@ -8,4 +8,6 @@ define i32 @callee_MissingRetAttr() {
   ret i32 -1
 }
 
-; CHECK: Narrow integer argument must have a valid extension type.
+; CHECK: ERROR: Missing extension attribute of returned value from function:
+; CHECK: i32 @callee_MissingRetAttr()
+; CHECK: UNREACHABLE executed
diff --git a/llvm/test/CodeGen/SystemZ/args-16.ll b/llvm/test/CodeGen/SystemZ/args-16.ll
index b76a2afea50775..846100146e7908 100644
--- a/llvm/test/CodeGen/SystemZ/args-16.ll
+++ b/llvm/test/CodeGen/SystemZ/args-16.ll
@@ -8,5 +8,7 @@ define i16 @callee_MissingRetAttr() {
   ret i16 -1
 }
 
-; CHECK: Narrow integer argument must have a valid extension type.
+; CHECK: ERROR: Missing extension attribute of returned value from function:
+; CHECK: i16 @callee_MissingRetAttr()
+; CHECK: UNREACHABLE executed
 
diff --git a/llvm/test/CodeGen/SystemZ/args-17.ll b/llvm/test/CodeGen/SystemZ/args-17.ll
index bce54b3d2aa1fe..4231d7e9e4772d 100644
--- a/llvm/test/CodeGen/SystemZ/args-17.ll
+++ b/llvm/test/CodeGen/SystemZ/args-17.ll
@@ -8,4 +8,6 @@ define i8 @callee_MissingRetAttr() {
   ret i8 -1
 }
 
-; CHECK: Narrow integer argument must have a valid extension type.
+; CHECK: ERROR: Missing extension attribute of returned value from function:
+; CHECK: i8 @callee_MissingRetAttr()
+; CHECK: UNREACHABLE executed
diff --git a/llvm/test/CodeGen/SystemZ/args-18.ll b/llvm/test/CodeGen/SystemZ/args-18.ll
index 82e9729d3a2dfd..bd368fa056c6c9 100644
--- a/llvm/test/CodeGen/SystemZ/args-18.ll
+++ b/llvm/test/CodeGen/SystemZ/args-18.ll
@@ -11,4 +11,6 @@ define void @caller() {
 
 declare void @bar_Struct(i32 %Arg)
 
-; CHECK: Narrow integer argument must have a valid extension type
+; CHECK: ERROR: Missing extension attribute of passed value in call to function:
+; CHECK: Callee:  void @bar_Struct(i32)
+; CHECK: Caller:  void @caller()
diff --git a/llvm/test/CodeGen/SystemZ/args-19.ll b/llvm/test/CodeGen/SystemZ/args-19.ll
index 40a794417b4c6f..8b5f421f59fdd8 100644
--- a/llvm/test/CodeGen/SystemZ/args-19.ll
+++ b/llvm/test/CodeGen/SystemZ/args-19.ll
@@ -11,4 +11,6 @@ define void @caller() {
 
 declare void @bar_Struct(i16 %Arg)
 
-; CHECK: Narrow integer argument must have a valid extension type
+; CHECK: ERROR: Missing extension attribute of passed value in call to function:
+; CHECK: Callee:  void @bar_Struct(i16)
+; CHECK: Caller:  void @caller()
diff --git a/llvm/test/CodeGen/SystemZ/args-20.ll b/llvm/test/CodeGen/SystemZ/args-20.ll
index ce8b828a2d539a..ed6f2e52bf6ee9 100644
--- a/llvm/test/CodeGen/SystemZ/args-20.ll
+++ b/llvm/test/CodeGen/SystemZ/args-20.ll
@@ -11,4 +11,6 @@ define void @caller() {
 
 declare void @bar_Struct(i8 %Arg)
 
-; CHECK: Narrow integer argument must have a valid extension type
+; CHECK: ERROR: Missing extension attribute of passed value in call to function:
+; CHECK: Callee:  void @bar_Struct(i8)
+; CHECK: Caller:  void @caller()
diff --git a/llvm/test/CodeGen/SystemZ/args-21.ll b/llvm/test/CodeGen/SystemZ/args-21.ll
index c64233094c7df9..da5c8fe5ffc7fc 100644
--- a/llvm/test/CodeGen/SystemZ/args-21.ll
+++ b/llvm/test/CodeGen/SystemZ/args-21.ll
@@ -16,4 +16,6 @@ define void @foo() {
   ret void
 }
 
-; CHECK: Narrow integer argument must have a valid extension type
+; CHECK: ERROR: Missing extension attribute of returned value from function:
+; CHECK: i32 @bar(i32)
+; CHECK: UNREACHABLE executed