Index: lib/Target/NVPTX/NVPTXISelLowering.h
===================================================================
--- lib/Target/NVPTX/NVPTXISelLowering.h
+++ lib/Target/NVPTX/NVPTXISelLowering.h
@@ -539,7 +539,7 @@
   SDValue PerformDAGCombine(SDNode *N, DAGCombinerInfo &DCI) const override;
 
   unsigned getArgumentAlignment(SDValue Callee, const ImmutableCallSite *CS,
-                                Type *Ty, unsigned Idx) const;
+                                Type *Ty, unsigned Idx, const DataLayout &DL) const;
 };
 } // namespace llvm
 
Index: lib/Target/NVPTX/NVPTXISelLowering.cpp
===================================================================
--- lib/Target/NVPTX/NVPTXISelLowering.cpp
+++ lib/Target/NVPTX/NVPTXISelLowering.cpp
@@ -1028,48 +1028,50 @@
 NVPTXTargetLowering::getArgumentAlignment(SDValue Callee,
                                           const ImmutableCallSite *CS,
                                           Type *Ty,
-                                          unsigned Idx) const {
-  unsigned Align = 0;
-  const Value *DirectCallee = CS->getCalledFunction();
-
-  if (!DirectCallee) {
-    // We don't have a direct function symbol, but that may be because of
-    // constant cast instructions in the call.
-    const Instruction *CalleeI = CS->getInstruction();
-    assert(CalleeI && "Call target is not a function or derived value?");
-
-    // With bitcast'd call targets, the instruction will be the call
-    if (isa<CallInst>(CalleeI)) {
-      // Check if we have call alignment metadata
-      if (llvm::getAlign(*cast<CallInst>(CalleeI), Idx, Align))
-        return Align;
+                                          unsigned Idx,
+                                          const DataLayout &DL) const {
+  if (CS) {
+    unsigned Align = 0;
+    const Value *DirectCallee = CS->getCalledFunction();
+
+    if (!DirectCallee) {
+      // We don't have a direct function symbol, but that may be because of
+      // constant cast instructions in the call.
+      const Instruction *CalleeI = CS->getInstruction();
+      assert(CalleeI && "Call target is not a function or derived value?");
+
+      // With bitcast'd call targets, the instruction will be the call
+      if (isa<CallInst>(CalleeI)) {
+        // Check if we have call alignment metadata
+        if (llvm::getAlign(*cast<CallInst>(CalleeI), Idx, Align))
+          return Align;
+
+        const Value *CalleeV = cast<CallInst>(CalleeI)->getCalledValue();
+        // Ignore any bitcast instructions
+        while(isa<ConstantExpr>(CalleeV)) {
+          const ConstantExpr *CE = cast<ConstantExpr>(CalleeV);
+          if (!CE->isCast())
+            break;
+          // Look through the bitcast
+          CalleeV = cast<ConstantExpr>(CalleeV)->getOperand(0);
+        }
 
-      const Value *CalleeV = cast<CallInst>(CalleeI)->getCalledValue();
-      // Ignore any bitcast instructions
-      while(isa<ConstantExpr>(CalleeV)) {
-        const ConstantExpr *CE = cast<ConstantExpr>(CalleeV);
-        if (!CE->isCast())
-          break;
-        // Look through the bitcast
-        CalleeV = cast<ConstantExpr>(CalleeV)->getOperand(0);
+        // We have now looked past all of the bitcasts.  Do we finally have a
+        // Function?
+        if (isa<Function>(CalleeV))
+          DirectCallee = CalleeV;
       }
-
-      // We have now looked past all of the bitcasts.  Do we finally have a
-      // Function?
-      if (isa<Function>(CalleeV))
-        DirectCallee = CalleeV;
     }
-  }
 
-  // Check for function alignment information if we found that the
-  // ultimate target is a Function
-  if (DirectCallee)
-    if (llvm::getAlign(*cast<Function>(DirectCallee), Idx, Align))
-      return Align;
+    // Check for function alignment information if we found that the
+    // ultimate target is a Function
+    if (DirectCallee)
+      if (llvm::getAlign(*cast<Function>(DirectCallee), Idx, Align))
+        return Align;
+  }
 
   // Call is indirect or alignment information is not available, fall back to
   // the ABI type alignment
-  auto &DL = CS->getCaller()->getParent()->getDataLayout();
   return DL.getABITypeAlignment(Ty);
 }
 
@@ -1126,7 +1128,7 @@
         ComputePTXValueVTs(*this, DAG.getDataLayout(), Ty, vtparts, &Offsets,
                            0);
 
-        unsigned align = getArgumentAlignment(Callee, CS, Ty, paramCount + 1);
+        unsigned align = getArgumentAlignment(Callee, CS, Ty, paramCount + 1, DL);
         // declare .param .align <align> .b8 .param<n>[<size>];
         unsigned sz = DL.getTypeAllocSize(Ty);
         SDVTList DeclareParamVTs = DAG.getVTList(MVT::Other, MVT::Glue);
@@ -1166,7 +1168,7 @@
       }
       if (Ty->isVectorTy()) {
         EVT ObjectVT = getValueType(DL, Ty);
-        unsigned align = getArgumentAlignment(Callee, CS, Ty, paramCount + 1);
+        unsigned align = getArgumentAlignment(Callee, CS, Ty, paramCount + 1, DL);
         // declare .param .align <align> .b8 .param<n>[<size>];
         unsigned sz = DL.getTypeAllocSize(Ty);
         SDVTList DeclareParamVTs = DAG.getVTList(MVT::Other, MVT::Glue);
@@ -1426,7 +1428,7 @@
                           DeclareRetOps);
       InFlag = Chain.getValue(1);
     } else {
-      retAlignment = getArgumentAlignment(Callee, CS, retTy, 0);
+      retAlignment = getArgumentAlignment(Callee, CS, retTy, 0, DL);
       SDVTList DeclareRetVTs = DAG.getVTList(MVT::Other, MVT::Glue);
       SDValue DeclareRetOps[] = { Chain,
                                   DAG.getConstant(retAlignment, dl, MVT::i32),
@@ -1633,9 +1635,10 @@
     } else {
       SmallVector<EVT, 16> VTs;
       SmallVector<uint64_t, 16> Offsets;
-      ComputePTXValueVTs(*this, DAG.getDataLayout(), retTy, VTs, &Offsets, 0);
+      auto &DL = DAG.getDataLayout();
+      ComputePTXValueVTs(*this, DL, retTy, VTs, &Offsets, 0);
       assert(VTs.size() == Ins.size() && "Bad value decomposition");
-      unsigned RetAlign = getArgumentAlignment(Callee, CS, retTy, 0);
+      unsigned RetAlign = getArgumentAlignment(Callee, CS, retTy, 0, DL);
       for (unsigned i = 0, e = Ins.size(); i != e; ++i) {
         unsigned sz = VTs[i].getSizeInBits();
         unsigned AlignI = GreatestCommonDivisor64(RetAlign, Offsets[i]);
Index: test/CodeGen/NVPTX/zero-cs.ll
===================================================================
--- /dev/null
+++ test/CodeGen/NVPTX/zero-cs.ll
@@ -0,0 +1,9 @@
+; RUN: not llc < %s -march=nvptx 2>&1 | FileCheck %s
+
+; CHECK: LLVM ERROR: Cannot select: t7: i32 = ExternalSymbol'__powidf2'
+define double @powi() {
+  %1 = call double @llvm.powi.f64(double 1.000000e+00, i32 undef)
+  ret double %1
+}
+
+declare double @llvm.powi.f64(double, i32) nounwind readnone