(Towards #3367) def use chain update for assignments.

src/psyclone/psyir/nodes/assignment.py

@@ -39,13 +39,14 @@
 
 ''' This module contains the Assignment node implementation.'''
 
-from psyclone.core import VariablesAccessMap, AccessType
+from psyclone.core import VariablesAccessMap, AccessType, Signature
 from psyclone.errors import InternalError
 from psyclone.psyir.nodes.literal import Literal
 from psyclone.psyir.nodes.array_reference import ArrayReference
 from psyclone.psyir.nodes.datanode import DataNode
 from psyclone.psyir.nodes.intrinsic_call import (
     IntrinsicCall, REDUCTION_INTRINSICS)
+from psyclone.psyir.nodes.node import Node
 from psyclone.psyir.nodes.ranges import Range
 from psyclone.psyir.nodes.reference import Reference
 from psyclone.psyir.nodes.statement import Statement
@@ -243,3 +244,39 @@ def is_literal_assignment(self):
 
         '''
         return isinstance(self.rhs, Literal)
+
+    def previous_accesses(self) -> dict[Signature, list[Node]]:
+        '''
+        :returns: the nodes containing the previous accesses of the symbols
+                  accessed within this node. It can be multiple nodes for
+                  each symbol if the control flow diverges and there are
+                  multiple possible accesses.
+        '''
+        # Find all of the read/write References in this assignment.
+        refs = []
+        for ref in self.walk(Reference):
+            if ref.is_read or ref.is_write:
+                refs.append(ref)
+        # Avoid circular import
+        # pylint: disable=import-outside-toplevel
+        from psyclone.psyir.tools import DefinitionUseChain
+        chain = DefinitionUseChain(refs)
+        return chain.find_backward_accesses()
+
+    def next_accesses(self) -> dict[Signature, list[Node]]:
+        '''
+        :returns: the nodes containing the next accesses of the symbols
+                  accessed within this node. It can be multiple nodes for
+                  each symbol if the control flow diverges and there are
+                  multiple possible accesses.
+        '''
+        # Find all of the read/write References in this assignment.
+        refs = []
+        for ref in self.walk(Reference):
+            if ref.is_read or ref.is_write:
+                refs.append(ref)
+        # Avoid circular import
+        # pylint: disable=import-outside-toplevel
+        from psyclone.psyir.tools import DefinitionUseChain
+        chain = DefinitionUseChain(refs)
+        return chain.find_forward_accesses()

src/psyclone/psyir/nodes/reference.py

@@ -45,7 +45,12 @@
 # We cannot import from 'nodes' directly due to circular import
 from psyclone.psyir.nodes.datanode import DataNode
 from psyclone.psyir.nodes.node import Node
-from psyclone.psyir.symbols import Symbol, AutomaticInterface
+from psyclone.psyir.symbols import (
+    Symbol,
+    AutomaticInterface,
+    RoutineSymbol,
+    IntrinsicSymbol
+)
 from psyclone.psyir.symbols.datatypes import UnresolvedType
 
 
@@ -95,6 +100,12 @@ def is_read(self):
         # pylint: disable=import-outside-toplevel
         from psyclone.psyir.nodes.assignment import Assignment
         from psyclone.psyir.nodes.intrinsic_call import IntrinsicCall
+
+        # If the symbol is a RoutineSymbol or IntrinsicSymbol we don't read
+        # the symbol.
+        if isinstance(self.symbol, (RoutineSymbol, IntrinsicSymbol)):
+            return False
+
         parent = self.parent
         if isinstance(parent, Assignment):
             if parent.lhs is self:
@@ -235,31 +246,31 @@ def datatype(self):
             return super().datatype
         return self.symbol.datatype
 
-    def previous_accesses(self):
+    def previous_accesses(self) -> list[Node]:
         '''
         :returns: the nodes accessing the same symbol directly before this
                   reference. It can be multiple nodes if the control flow
                   diverges and there are multiple possible accesses.
-        :rtype: List[:py:class:`psyclone.psyir.nodes.Node`]
         '''
         # Avoid circular import
         # pylint: disable=import-outside-toplevel
         from psyclone.psyir.tools import DefinitionUseChain
         chain = DefinitionUseChain(self)
-        return chain.find_backward_accesses()
+        sig = self.get_signature_and_indices()[0]
+        return chain.find_backward_accesses()[sig]
 
-    def next_accesses(self):
+    def next_accesses(self) -> list[Node]:
         '''
         :returns: the nodes accessing the same symbol directly after this
                   reference. It can be multiple nodes if the control flow
                   diverges and there are multiple possible accesses.
-        :rtype: List[:py:class:`psyclone.psyir.nodes.Node`]
         '''
         # Avoid circular import
         # pylint: disable=import-outside-toplevel
         from psyclone.psyir.tools import DefinitionUseChain
         chain = DefinitionUseChain(self)
-        return chain.find_forward_accesses()
+        sig = self.get_signature_and_indices()[0]
+        return chain.find_forward_accesses()[sig]
 
     def escapes_scope(
             self, scope: Node, visited_nodes: Optional[set] = None