[mlir][sparse] Fix Python interface for bufferization.alloc_tensor.

[bixia]

Summary

Add size_hint operand to the Python interface.
Fix pytaco.

mlir/python/mlir/dialects/_bufferization_ops_ext.py

 
 class AllocTensorOp:
   """Extends the bufferization.alloc_tensor op."""
 
   def __init__(self,
                tensor_type: Type,
                dynamic_sizes: Sequence[Value],
                copy: Value,
+               size_hint: Value,
                escape: BoolAttr,
                *,
                loc=None,
                ip=None):
     """Constructs an `alloc_tensor` with static and/or dynamic sizes."""
     context = get_default_loc_context(loc)
     attributes = {}
     if escape:
       attributes["escape"] = escape
     op = self.build_generic(
         results=[tensor_type],
-        operands=[dynamic_sizes, copy],
+        operands=[dynamic_sizes, copy, size_hint],
         attributes=attributes,
         loc=loc,
         ip=ip)
     OpView.__init__(self, op)

mlir/test/Integration/Dialect/SparseTensor/taco/tools/mlir_pytaco.py

if self.dst_format is None or self.dst_format.rank() == 0:
       empty = tensor.EmptyOp(self.dst_dims, ir_type).result
       zero = arith.ConstantOp(ir_type, 0.0)
       return linalg.fill(zero, outs=[empty])
 
     # Initialize the sparse tensor.
     mlir_type = _mlir_tensor_type(self.dst_dtype, self.dst_dims,
                                   self.dst_format.mlir_tensor_attr())
     index_type = ir.IndexType.get()
-    return bufferization.AllocTensorOp(mlir_type, [], None, None)
+    return bufferization.AllocTensorOp(mlir_type, [], None, None, None)
 
 
 class _Stats:
   """Information to describe how a tensor expression is implemented.
 
   Currently, we only record the temporary tensors introduced for splitting the
   original expression.
   """