Index: llvm/trunk/lib/Target/NVPTX/NVPTXISelLowering.cpp
===================================================================
--- llvm/trunk/lib/Target/NVPTX/NVPTXISelLowering.cpp
+++ llvm/trunk/lib/Target/NVPTX/NVPTXISelLowering.cpp
@@ -1661,7 +1661,12 @@
     }
   }
 
-  if (!Func) {
+  // Both indirect calls and libcalls have nullptr Func. In order to distinguish
+  // between them we must rely on the call site value which is valid for
+  // indirect calls but is always null for libcalls.
+  bool isIndirectCall = !Func && CS;
+
+  if (isIndirectCall) {
     // This is indirect function call case : PTX requires a prototype of the
     // form
     // proto_0 : .callprototype(.param .b32 _) _ (.param .b32 _);
@@ -1685,7 +1690,7 @@
     Chain, DAG.getConstant((Ins.size() == 0) ? 0 : 1, dl, MVT::i32), InFlag
   };
   // We model convergent calls as separate opcodes.
-  unsigned Opcode = Func ? NVPTXISD::PrintCallUni : NVPTXISD::PrintCall;
+  unsigned Opcode = isIndirectCall ? NVPTXISD::PrintCall : NVPTXISD::PrintCallUni;
   if (CLI.IsConvergent)
     Opcode = Opcode == NVPTXISD::PrintCallUni ? NVPTXISD::PrintConvergentCallUni
                                               : NVPTXISD::PrintConvergentCall;
@@ -1719,12 +1724,12 @@
   }
   SDVTList CallArgEndVTs = DAG.getVTList(MVT::Other, MVT::Glue);
   SDValue CallArgEndOps[] = { Chain,
-                              DAG.getConstant(Func ? 1 : 0, dl, MVT::i32),
+                              DAG.getConstant(isIndirectCall ? 0 : 1, dl, MVT::i32),
                               InFlag };
   Chain = DAG.getNode(NVPTXISD::CallArgEnd, dl, CallArgEndVTs, CallArgEndOps);
   InFlag = Chain.getValue(1);
 
-  if (!Func) {
+  if (isIndirectCall) {
     SDVTList PrototypeVTs = DAG.getVTList(MVT::Other, MVT::Glue);
     SDValue PrototypeOps[] = { Chain,
                                DAG.getConstant(uniqueCallSite, dl, MVT::i32),
Index: llvm/trunk/test/CodeGen/NVPTX/libcall-instruction.ll
===================================================================
--- llvm/trunk/test/CodeGen/NVPTX/libcall-instruction.ll
+++ llvm/trunk/test/CodeGen/NVPTX/libcall-instruction.ll
@@ -0,0 +1,8 @@
+; RUN: not llc < %s -march=nvptx 2>&1 | FileCheck %s
+; used to panic on failed assetion and now fails with a "Cannot select"
+
+; CHECK: LLVM ERROR: Cannot select: {{t28|0x[0-9a-f]+}}: i32 = ExternalSymbol'__umodti3'
+define hidden i128 @remainder(i128, i128) {
+  %3 = urem i128 %0, %1
+  ret i128 %3
+}