Add convenience builder for MemRefType.

PiperOrigin-RevId: 208245701
diff --git a/include/mlir/IR/Builders.h b/include/mlir/IR/Builders.h
index af089e6..3324d4b 100644
--- a/include/mlir/IR/Builders.h
+++ b/include/mlir/IR/Builders.h
@@ -70,6 +70,9 @@
   IntegerType *getIntegerType(unsigned width);
   FunctionType *getFunctionType(ArrayRef<Type *> inputs,
                                 ArrayRef<Type *> results);
+  MemRefType *getMemRefType(ArrayRef<int> shape, Type *elementType,
+                            ArrayRef<AffineMap *> affineMapComposition = {},
+                            unsigned memorySpace = 0);
   VectorType *getVectorType(ArrayRef<unsigned> shape, Type *elementType);
   RankedTensorType *getTensorType(ArrayRef<int> shape, Type *elementType);
   UnrankedTensorType *getTensorType(Type *elementType);