Fix a crash when faced with a shuffle vector that has an undef in its mask.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@27726 91177308-0d34-0410-b5e6-96231b3b80d8

diff --git a/lib/Target/PowerPC/PPCISelLowering.cpp b/lib/Target/PowerPC/PPCISelLowering.cpp
index 8fa5f84db53ccfd84574cc82ac425ae1f1aac556..826ff4ea8197fd8c1800412935bf46c2af115c4e 100644 (file)
--- a/lib/Target/PowerPC/PPCISelLowering.cpp
+++ b/lib/Target/PowerPC/PPCISelLowering.cpp
@@ -1116,7 +1116,11 @@ static SDOperand LowerVECTOR_SHUFFLE(SDOperand Op, SelectionDAG &DAG) {
   
   std::vector<SDOperand> ResultMask;
   for (unsigned i = 0, e = PermMask.getNumOperands(); i != e; ++i) {
-    unsigned SrcElt =cast<ConstantSDNode>(PermMask.getOperand(i))->getValue();
+    unsigned SrcElt;
+    if (PermMask.getOperand(i).getOpcode() == ISD::UNDEF)
+      SrcElt = 0;
+    else 
+      SrcElt = cast<ConstantSDNode>(PermMask.getOperand(i))->getValue();
     
     for (unsigned j = 0; j != BytesPerElement; ++j)
       ResultMask.push_back(DAG.getConstant(SrcElt*BytesPerElement+j,