def __init__(self, *args, **kwargs):
self._entry = nodes.EntryNode()
self._tasklet = nodes.Tasklet('_')
self._exit = nodes.ExitNode()
super().__init__(*args, **kwargs)
class MapFusion(pattern_matching.Transformation):
""" Implements the MapFusion transformation.
It wil check for all patterns MapExit -> AccessNode -> MapEntry, and
based on the following rules, fuse them and remove the transient in
between. There are several possibilities of what it does to this
transient in between.
Essentially, if there is some other place in the
sdfg where it is required, or if it is not a transient, then it will
not be removed. In such a case, it will be linked to the MapExit node
of the new fused map.
Rules for fusing maps:
0. The map range of the second map should be a permutation of the
first map range.
1. Each of the access nodes that are adjacent to the first map exit
should have an edge to the second map entry. If it doesn't, then the
second map entry should not be reachable from this access node.
2. Any node that has a wcr from the first map exit should not be
adjacent to the second map entry.
3. Access pattern for the access nodes in the second map should be
the same permutation of the map parameters as the map ranges of the
two maps. Alternatively, this access node should not be adjacent to
the first map entry.
"""
_first_map_exit = nodes.ExitNode()
_some_array = nodes.AccessNode("_")
_second_map_entry = nodes.EntryNode()
@staticmethod
def annotates_memlets():
return False
@staticmethod
def expressions():
return [
sdutil.node_path_graph(
MapFusion._first_map_exit,
MapFusion._some_array,
MapFusion._second_map_entry,
)
]
@staticmethod
def find_permutation(first_map: nodes.Map,
second_map: nodes.Map) -> Union[List[int], None]:
""" Find permutation between two map ranges.
:param first_map: First map.
:param second_map: Second map.
:return: None if no such permutation exists, otherwise a list of
indices L such that L[x]'th parameter of second map has the same range as x'th
parameter of the first map.
"""
result = []
if len(first_map.range) != len(second_map.range):
return None
# Match map ranges with reduce ranges
for i, tmap_rng in enumerate(first_map.range):
found = False
for j, rng in enumerate(second_map.range):
if tmap_rng == rng and j not in result:
result.append(j)
found = True
break
if not found:
break
# Ensure all map ranges matched
if len(result) != len(first_map.range):
return None
return result
@staticmethod
def can_be_applied(graph, candidate, expr_index, sdfg, strict=False):
first_map_exit = graph.nodes()[candidate[MapFusion._first_map_exit]]
first_map_entry = graph.entry_node(first_map_exit)
second_map_entry = graph.nodes()[candidate[
MapFusion._second_map_entry]]
for _in_e in graph.in_edges(first_map_exit):
if _in_e.data.wcr is not None:
for _out_e in graph.out_edges(second_map_entry):
if _out_e.data.data == _in_e.data.data:
# wcr is on a node that is used in the second map, quit
return False
# Check whether there is a pattern map -> access -> map.
intermediate_nodes = set()
intermediate_data = set()
for _, _, dst, _, _ in graph.out_edges(first_map_exit):
if isinstance(dst, nodes.AccessNode):
intermediate_nodes.add(dst)
intermediate_data.add(dst.data)
# If array is used anywhere else in this state.
num_occurrences = len([
n for n in graph.nodes()
if isinstance(n, nodes.AccessNode) and n.data == dst.data
])
if num_occurrences > 1:
return False
else:
return False
# Check map ranges
perm = MapFusion.find_permutation(first_map_entry.map,
second_map_entry.map)
if perm is None:
return False
# Check if any intermediate transient is also going to another location
second_inodes = set(e.src for e in graph.in_edges(second_map_entry)
if isinstance(e.src, nodes.AccessNode))
transients_to_remove = intermediate_nodes & second_inodes
# if any(e.dst != second_map_entry for n in transients_to_remove
# for e in graph.out_edges(n)):
if any(graph.out_degree(n) > 1 for n in transients_to_remove):
return False
# Create a dict that maps parameters of the first map to those of the
# second map.
params_dict = {}
for _index, _param in enumerate(first_map_entry.map.params):
params_dict[_param] = second_map_entry.map.params[perm[_index]]
out_memlets = [e.data for e in graph.in_edges(first_map_exit)]
# Check that input set of second map is provided by the output set
# of the first map, or other unrelated maps
for second_edge in graph.out_edges(second_map_entry):
# Memlets that do not come from one of the intermediate arrays
if second_edge.data.data not in intermediate_data:
# however, if intermediate_data eventually leads to
# second_memlet.data, need to fail.
for _n in intermediate_nodes:
source_node = _n
destination_node = graph.memlet_path(second_edge)[0].src
# NOTE: Assumes graph has networkx version
if destination_node in nx.descendants(
graph._nx, source_node):
return False
continue
provided = False
# Compute second subset with respect to first subset's symbols
sbs_permuted = dcpy(second_edge.data.subset)
sbs_permuted.replace({
symbolic.pystr_to_symbolic(k): symbolic.pystr_to_symbolic(v)
for k, v in params_dict.items()
})
for first_memlet in out_memlets:
if first_memlet.data != second_edge.data.data:
continue
# If there is a covered subset, it is provided
if first_memlet.subset.covers(sbs_permuted):
provided = True
break
# If none of the output memlets of the first map provide the info,
# fail.
if provided is False:
return False
# Success
return True
@staticmethod
def match_to_str(graph, candidate):
first_exit = graph.nodes()[candidate[MapFusion._first_map_exit]]
second_entry = graph.nodes()[candidate[MapFusion._second_map_entry]]
return " -> ".join(entry.map.label + ": " + str(entry.map.params)
for entry in [first_exit, second_entry])
def apply(self, sdfg):
"""
This method applies the mapfusion transformation.
Other than the removal of the second map entry node (SME), and the first
map exit (FME) node, it has the following side effects:
1. Any transient adjacent to both FME and SME with degree = 2 will be removed.
The tasklets that use/produce it shall be connected directly with a
scalar/new transient (if the dataflow is more than a single scalar)
2. If this transient is adjacent to FME and SME and has other
uses, it will be adjacent to the new map exit post fusion.
Tasklet-> Tasklet edges will ALSO be added as mentioned above.
3. If an access node is adjacent to FME but not SME, it will be
adjacent to new map exit post fusion.
4. If an access node is adjacent to SME but not FME, it will be
adjacent to the new map entry node post fusion.
"""
graph = sdfg.nodes()[self.state_id]
first_exit = graph.nodes()[self.subgraph[MapFusion._first_map_exit]]
first_entry = graph.entry_node(first_exit)
second_entry = graph.nodes()[self.subgraph[
MapFusion._second_map_entry]]
second_exit = graph.exit_node(second_entry)
intermediate_nodes = set()
for _, _, dst, _, _ in graph.out_edges(first_exit):
intermediate_nodes.add(dst)
assert isinstance(dst, nodes.AccessNode)
# Check if an access node refers to non transient memory, or transient
# is used at another location (cannot erase)
do_not_erase = set()
for node in intermediate_nodes:
if sdfg.arrays[node.data].transient is False:
do_not_erase.add(node)
else:
for edge in graph.in_edges(node):
if edge.src != first_exit:
do_not_erase.add(node)
break
else:
for edge in graph.out_edges(node):
if edge.dst != second_entry:
do_not_erase.add(node)
break
# Find permutation between first and second scopes
perm = MapFusion.find_permutation(first_entry.map, second_entry.map)
params_dict = {}
for index, param in enumerate(first_entry.map.params):
params_dict[param] = second_entry.map.params[perm[index]]
# Replaces (in memlets and tasklet) the second scope map
# indices with the permuted first map indices.
# This works in two passes to avoid problems when e.g., exchanging two
# parameters (instead of replacing (j,i) and (i,j) to (j,j) and then
# i,i).
second_scope = graph.scope_subgraph(second_entry)
for firstp, secondp in params_dict.items():
if firstp != secondp:
replace(second_scope, secondp, '__' + secondp + '_fused')
for firstp, secondp in params_dict.items():
if firstp != secondp:
replace(second_scope, '__' + secondp + '_fused', firstp)
# Isolate First exit node
############################
edges_to_remove = set()
nodes_to_remove = set()
for edge in graph.in_edges(first_exit):
tree = graph.memlet_tree(edge)
access_node = tree.root().edge.dst
if access_node not in do_not_erase:
out_edges = [
e for e in graph.out_edges(access_node)
if e.dst == second_entry
]
# In this transformation, there can only be one edge to the
# second map
assert len(out_edges) == 1
# Get source connector to the second map
connector = out_edges[0].dst_conn[3:]
new_dsts = []
# Look at the second map entry out-edges to get the new
# destinations
for e in graph.out_edges(second_entry):
if e.src_conn[4:] == connector:
new_dsts.append(e)
if not new_dsts: # Access node is not used in the second map
nodes_to_remove.add(access_node)
continue
# If the source is an access node, modify the memlet to point
# to it
if (isinstance(edge.src, nodes.AccessNode)
and edge.data.data != edge.src.data):
edge.data.data = edge.src.data
edge.data.subset = ("0" if edge.data.other_subset is None
else edge.data.other_subset)
edge.data.other_subset = None
else:
# Add a transient scalar/array
self.fuse_nodes(sdfg, graph, edge, new_dsts[0].dst,
new_dsts[0].dst_conn, new_dsts[1:])
edges_to_remove.add(edge)
# Remove transient node between the two maps
nodes_to_remove.add(access_node)
else: # The case where intermediate array node cannot be removed
# Node will become an output of the second map exit
out_e = tree.parent.edge
conn = second_exit.next_connector()
graph.add_edge(
second_exit,
'OUT_' + conn,
out_e.dst,
out_e.dst_conn,
dcpy(out_e.data),
)
second_exit.add_out_connector('OUT_' + conn)
graph.add_edge(edge.src, edge.src_conn, second_exit,
'IN_' + conn, dcpy(edge.data))
second_exit.add_in_connector('IN_' + conn)
edges_to_remove.add(out_e)
edges_to_remove.add(edge)
# If the second map needs this node, link the connector
# that generated this to the place where it is needed, with a
# temp transient/scalar for memlet to be generated
for out_e in graph.out_edges(second_entry):
second_memlet_path = graph.memlet_path(out_e)
source_node = second_memlet_path[0].src
if source_node == access_node:
self.fuse_nodes(sdfg, graph, edge, out_e.dst,
out_e.dst_conn)
###
# First scope exit is isolated and can now be safely removed
for e in edges_to_remove:
graph.remove_edge(e)
graph.remove_nodes_from(nodes_to_remove)
graph.remove_node(first_exit)
# Isolate second_entry node
###########################
for edge in graph.in_edges(second_entry):
tree = graph.memlet_tree(edge)
access_node = tree.root().edge.src
if access_node in intermediate_nodes:
# Already handled above, can be safely removed
graph.remove_edge(edge)
continue
# This is an external input to the second map which will now go
# through the first map.
conn = first_entry.next_connector()
graph.add_edge(edge.src, edge.src_conn, first_entry, 'IN_' + conn,
dcpy(edge.data))
first_entry.add_in_connector('IN_' + conn)
graph.remove_edge(edge)
for out_enode in tree.children:
out_e = out_enode.edge
graph.add_edge(
first_entry,
'OUT_' + conn,
out_e.dst,
out_e.dst_conn,
dcpy(out_e.data),
)
graph.remove_edge(out_e)
first_entry.add_out_connector('OUT_' + conn)
###
# Second node is isolated and can now be safely removed
graph.remove_node(second_entry)
# Fix scope exit to point to the right map
second_exit.map = first_entry.map
def fuse_nodes(self,
sdfg,
graph,
edge,
new_dst,
new_dst_conn,
other_edges=None):
""" Fuses two nodes via memlets and possibly transient arrays. """
other_edges = other_edges or []
memlet_path = graph.memlet_path(edge)
access_node = memlet_path[-1].dst
local_name = "__s%d_n%d%s_n%d%s" % (
self.state_id,
graph.node_id(edge.src),
edge.src_conn,
graph.node_id(edge.dst),
edge.dst_conn,
)
# Add intermediate memory between subgraphs. If a scalar,
# uses direct connection. If an array, adds a transient node
if edge.data.subset.num_elements() == 1:
sdfg.add_scalar(
local_name,
dtype=access_node.desc(graph).dtype,
transient=True,
storage=dtypes.StorageType.Register,
)
edge.data.data = local_name
edge.data.subset = "0"
local_node = edge.src
src_connector = edge.src_conn
# Add edge that leads to the second node
graph.add_edge(local_node, src_connector, new_dst, new_dst_conn,
dcpy(edge.data))
for e in other_edges:
graph.add_edge(local_node, src_connector, e.dst, e.dst_conn,
dcpy(edge.data))
else:
sdfg.add_transient(local_name,
edge.data.subset.size(),
dtype=access_node.desc(graph).dtype)
old_edge = dcpy(edge)
local_node = graph.add_access(local_name)
src_connector = None
edge.data.data = local_name
edge.data.subset = ",".join(
["0:" + str(s) for s in edge.data.subset.size()])
# Add edge that leads to transient node
graph.add_edge(
edge.src,
edge.src_conn,
local_node,
None,
dcpy(edge.data),
)
# Add edge that leads to the second node
graph.add_edge(local_node, src_connector, new_dst, new_dst_conn,
dcpy(edge.data))
for e in other_edges:
graph.add_edge(local_node, src_connector, e.dst, e.dst_conn,
dcpy(edge.data))
# Modify data and memlets on all surrounding edges to match array
for neighbor in graph.all_edges(local_node):
for e in graph.memlet_tree(neighbor):
e.data.data = local_name
e.data.subset.offset(old_edge.data.subset, negative=True)
class OutMergeArrays(pattern_matching.Transformation):
""" Merge duplicate arrays connected to the same scope entry. """
_array1 = nodes.AccessNode("_")
_array2 = nodes.AccessNode("_")
_map_exit = nodes.ExitNode()
@staticmethod
def expressions():
# Matching
# \======/
# | |
# o o
g = SDFGState()
g.add_node(OutMergeArrays._array1)
g.add_node(OutMergeArrays._array2)
g.add_node(OutMergeArrays._map_exit)
g.add_edge(OutMergeArrays._map_exit, None, OutMergeArrays._array1,
None, memlet.Memlet())
g.add_edge(OutMergeArrays._map_exit, None, OutMergeArrays._array2,
None, memlet.Memlet())
return [g]
@staticmethod
def can_be_applied(graph, candidate, expr_index, sdfg, strict=False):
arr1_id = candidate[OutMergeArrays._array1]
arr2_id = candidate[OutMergeArrays._array2]
# Ensure both arrays contain the same data
arr1 = graph.node(arr1_id)
arr2 = graph.node(arr2_id)
if arr1.data != arr2.data:
return False
# Ensure only arr1's node ID contains outgoing edges
if graph.out_degree(arr2) > 0:
return False
# Ensure arr1 and arr2's node IDs are ordered (avoid duplicates)
if (graph.out_degree(arr1) == 0 and graph.out_degree(arr2) == 0
and arr1_id >= arr2_id):
return False
map = graph.node(candidate[OutMergeArrays._map_exit])
if (any(e.src != map for e in graph.in_edges(arr1))
or any(e.src != map for e in graph.in_edges(arr2))):
return False
# Ensure arr1 and arr2 are the first two sink nodes (avoid further
# duplicates)
all_sink_nodes = set(
graph.node_id(e.dst) for e in graph.out_edges(map) if e.dst != arr1
and e.dst != arr2 and e.dst.data == arr1.data and e.src_conn
and e.src_conn.startswith('OUT_') and graph.out_degree(e.dst) == 0)
if any(nid < arr1_id or nid < arr2_id for nid in all_sink_nodes):
return False
return True
@staticmethod
def match_to_str(graph, candidate):
arr = graph.node(candidate[OutMergeArrays._array1])
map = graph.node(candidate[OutMergeArrays._map_exit])
return '%s (%d, %d) -> %s' % (
arr.data, candidate[OutMergeArrays._array1],
candidate[OutMergeArrays._array2], map.label)
def apply(self, sdfg):
graph = sdfg.node(self.state_id)
array = graph.node(self.subgraph[OutMergeArrays._array1])
map = graph.node(self.subgraph[OutMergeArrays._map_exit])
map_edge = next(e for e in graph.in_edges(array) if e.src == map)
result_connector = map_edge.src_conn[4:]
# Find all other outgoing access nodes without outgoing edges
dst_edges = [
e for e in graph.out_edges(map)
if isinstance(e.dst, nodes.AccessNode) and e.dst.data == array.data
and e.dst != array and e.src_conn and e.src_conn.startswith('OUT_')
and graph.out_degree(e.dst) == 0
]
# Modify connectors to point to first array
connectors_to_remove = set()
for e in dst_edges:
connector = e.src_conn[4:]
connectors_to_remove.add(connector)
for inner_edge in graph.in_edges(map):
if inner_edge.dst_conn[3:] == connector:
inner_edge.dst_conn = 'IN_' + result_connector
# Remove other nodes from state
graph.remove_nodes_from(set(e.dst for e in dst_edges))
# Remove connectors from scope entry
for c in connectors_to_remove:
map.remove_in_connector('IN_' + c)
map.remove_out_connector('OUT_' + c)
# Re-propagate memlets
edge_to_propagate = next(e for e in graph.in_edges(map)
if e.dst_conn[3:] == result_connector)
map_edge._data = propagate_memlet(dfg_state=graph,
memlet=edge_to_propagate.data,
scope_node=map,
union_inner_edges=True)
