Add VectorTargetTransform::getNumberOfParts.

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

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@166751 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/include/llvm/Target/TargetTransformImpl.h b/include/llvm/Target/TargetTransformImpl.h
index 25a7ede..133be87 100644
--- a/include/llvm/Target/TargetTransformImpl.h
+++ b/include/llvm/Target/TargetTransformImpl.h
@@ -68,6 +68,8 @@
   virtual unsigned getMemoryOpCost(unsigned Opcode, Type *Src,
                                    unsigned Alignment,
                                    unsigned AddressSpace) const;
+
+  virtual unsigned getNumberOfParts(Type *Tp) const;
 };
 
 } // end llvm namespace
diff --git a/include/llvm/TargetTransformInfo.h b/include/llvm/TargetTransformInfo.h
index 96470c3..71c78ec 100644
--- a/include/llvm/TargetTransformInfo.h
+++ b/include/llvm/TargetTransformInfo.h
@@ -156,6 +156,11 @@
     return 1;
   }
 
+  /// Returns the number of pieces into which the provided type must be
+  /// split during legalization. Zero is returned when the answer is unknown.
+  virtual unsigned getNumberOfParts(Type *Tp) const {
+    return 0;
+  }
 };
 
 } // End llvm namespace
diff --git a/lib/Target/TargetTransformImpl.cpp b/lib/Target/TargetTransformImpl.cpp
index c8bd80e..3bf4bf7 100644
--- a/lib/Target/TargetTransformImpl.cpp
+++ b/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;
+}
+