Add VectorTargetTransform::getNumberOfParts.

As discussed on IRC, add VectorTargetTransform::getNumberOfParts
to provide a stable interface to the vector legalization splitting factor.

llvm-svn: 166751
diff --git a/llvm/lib/Target/TargetTransformImpl.cpp b/llvm/lib/Target/TargetTransformImpl.cpp
index c8bd80e..3bf4bf7 100644
--- a/llvm/lib/Target/TargetTransformImpl.cpp
+++ b/llvm/lib/Target/TargetTransformImpl.cpp
@@ -196,3 +196,11 @@
   // Assume that all loads of legal types cost 1.
   return LT.first;
 }
+
+unsigned
+VectorTargetTransformImpl::getNumberOfParts(Type *Tp) const {
+  std::pair<unsigned, EVT>  LT =
+  getTypeLegalizationCost(Tp->getContext(), TLI->getValueType(Tp));
+  return LT.first;
+}
+