Allow undef in a shuffle mask


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@27714 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/lib/Target/PowerPC/PPCISelLowering.cpp b/lib/Target/PowerPC/PPCISelLowering.cpp
index 99d3a47..8fa5f84 100644
--- a/lib/Target/PowerPC/PPCISelLowering.cpp
+++ b/lib/Target/PowerPC/PPCISelLowering.cpp
@@ -416,6 +416,7 @@
   
   assert(isa<ConstantSDNode>(Elt) && "Invalid VECTOR_SHUFFLE mask!");
   for (unsigned i = EltSize, e = 16; i != e; i += EltSize) {
+    if (N->getOperand(i).getOpcode() == ISD::UNDEF) continue;
     assert(isa<ConstantSDNode>(N->getOperand(i)) &&
            "Invalid VECTOR_SHUFFLE mask!");
     for (unsigned j = 0; j != EltSize; ++j)