Add VectorTargetTransform::getNumberOfParts.

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

llvm-svn: 166751

llvm/include/llvm/Target/TargetTransformImpl.h

@@ -68,6 +68,8 @@ public:
   virtual unsigned getMemoryOpCost(unsigned Opcode, Type *Src,
                                    unsigned Alignment,
                                    unsigned AddressSpace) const;
+
+  virtual unsigned getNumberOfParts(Type *Tp) const;
 };
 
 } // end llvm namespace

llvm/include/llvm/TargetTransformInfo.h

@@ -156,6 +156,11 @@ public:
     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

llvm/lib/Target/TargetTransformImpl.cpp

@@ -196,3 +196,11 @@ VectorTargetTransformImpl::getMemoryOpCost(unsigned Opcode, Type *Src,
   // 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;
+}
+