Index: lib/Target/NVPTX/NVPTXISelLowering.h
===================================================================
--- lib/Target/NVPTX/NVPTXISelLowering.h
+++ lib/Target/NVPTX/NVPTXISelLowering.h
@@ -539,7 +539,8 @@
   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
@@ -1024,11 +1024,15 @@
   return O.str();
 }
 
-unsigned
-NVPTXTargetLowering::getArgumentAlignment(SDValue Callee,
-                                          const ImmutableCallSite *CS,
-                                          Type *Ty,
-                                          unsigned Idx) const {
+unsigned NVPTXTargetLowering::getArgumentAlignment(SDValue Callee,
+                                                   const ImmutableCallSite *CS,
+                                                   Type *Ty, unsigned Idx,
+                                                   const DataLayout &DL) const {
+  if (!CS) {
+    // CallSite is zero, fallback to ABI type alignment
+    return DL.getABITypeAlignment(Ty);
+  }
+
   unsigned Align = 0;
   const Value *DirectCallee = CS->getCalledFunction();
 
@@ -1046,7 +1050,7 @@
 
       const Value *CalleeV = cast<CallInst>(CalleeI)->getCalledValue();
       // Ignore any bitcast instructions
-      while(isa<ConstantExpr>(CalleeV)) {
+      while (isa<ConstantExpr>(CalleeV)) {
         const ConstantExpr *CE = cast<ConstantExpr>(CalleeV);
         if (!CE->isCast())
           break;
@@ -1069,7 +1073,6 @@
 
   // 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 +1129,8 @@
         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 +1170,8 @@
       }
       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 +1431,7 @@
                           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 +1638,10 @@
     } 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 +1,10 @@
+; RUN: not llc < %s -march=nvptx 2>&1 | FileCheck %s
+; used to seqfault and now fails with a "Cannot select"
+
+; 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