Split local_useless_AdvancedSubtensor1 from local_useless_subtensor

Author: brandonwillard

aesara/tensor/subtensor_opt.py

@@ -879,135 +879,142 @@ def local_set_to_inc_subtensor(fgraph, node):
 
 @register_canonicalize
 @register_specialize
-@local_optimizer([Subtensor, AdvancedSubtensor1])
+@local_optimizer([Subtensor])
 def local_useless_subtensor(fgraph, node):
-    """
-    Remove Subtensor/AdvancedSubtensor1 if it takes the full input. In the
-    AdvancedSubtensor1 case, the full input is taken when the indices are
-    equivalent to `arange(0, input.shape[0], 1)` using either an explicit
-    list/vector or the ARange op.
-
-    """
+    """Remove `Subtensor` if it takes the full input."""
     # This optimization needs ShapeOpt and fgraph.shape_feature
     if not hasattr(fgraph, "shape_feature"):
         return
 
     shape_of = fgraph.shape_feature.shape_of
 
-    if isinstance(node.op, Subtensor):
-        cdata = get_constant_idx(
-            node.op.idx_list,
-            node.inputs,
-            allow_partial=True,
-            only_process_constants=True,
-        )
-        for pos, idx in enumerate(cdata):
-            if not isinstance(idx, slice):
-                # If idx is not a slice, this means we remove this dimension
-                # from the output, so the subtensor is not useless
-                return False
-            if idx.start is not None and idx.start != 0:
-                # If the start of the slice is different from 0, or is a
-                # variable, then we assume the subtensor is not useless
-                return False
-            if idx.step is not None and idx.step != 1:
-                # If we are going backwards, or skipping elements, then this
-                # is not a useless subtensor
-                return False
-
-        for pos, idx in enumerate(cdata):
-
-            length_pos = shape_of[node.inputs[0]][pos]
-
-            if isinstance(idx.stop, (int, np.integer)):
-                length_pos_data = sys.maxsize
-                try:
-                    length_pos_data = get_scalar_constant_value(
-                        length_pos, only_process_constants=True
-                    )
-                except NotScalarConstantError:
-                    pass
-
-                if idx.stop < length_pos_data:
-                    return False
-            elif isinstance(idx.stop, Variable):
-                length_pos_shape_i = idx.stop
-                # length_pos is a tensor variable, but length_pos_shape_i
-                # is a scalar variable. We try to see if they represent
-                # the same underlying variable.
-                if length_pos_shape_i.owner and isinstance(
-                    length_pos_shape_i.owner.op, ScalarFromTensor
-                ):
-                    length_pos_shape_i = length_pos_shape_i.owner.inputs[0]
-                elif length_pos.owner and isinstance(
-                    length_pos.owner.op, TensorFromScalar
-                ):
-                    length_pos = length_pos.owner.inputs[0]
-                else:
-                    # We did not find underlying variables of the same type
-                    return False
-
-                # The type can be different: int32 vs int64. length_pos
-                # should always be int64 as that is what the shape
-                # tracker keep. Subtensor accept any scalar int{8,16,32,64}
-                # as index type.
-                assert str(length_pos.type.dtype) == "int64"
-                assert str(length_pos_shape_i.type.dtype) in [
-                    "int8",
-                    "int16",
-                    "int32",
-                    "int64",
-                ]
-
-                # length_pos_shape_i cannot be None
-                if length_pos_shape_i != length_pos:
-                    return False
-            elif idx.stop is None:
-                pass
-            else:
-                return False
-    elif isinstance(node.op, AdvancedSubtensor1):
-        # get length of the indexed tensor along the first axis
-        try:
-            length = get_scalar_constant_value(
-                shape_of[node.inputs[0]][0], only_process_constants=True
-            )
-        except NotScalarConstantError:
+    cdata = get_constant_idx(
+        node.op.idx_list,
+        node.inputs,
+        allow_partial=True,
+        only_process_constants=True,
+    )
+    for pos, idx in enumerate(cdata):
+        if not isinstance(idx, slice):
+            # If idx is not a slice, this means we remove this dimension
+            # from the output, so the subtensor is not useless
+            return False
+        if idx.start is not None and idx.start != 0:
+            # If the start of the slice is different from 0, or is a
+            # variable, then we assume the subtensor is not useless
+            return False
+        if idx.step is not None and idx.step != 1:
+            # If we are going backwards, or skipping elements, then this
+            # is not a useless subtensor
             return False
 
-        # get index (which must be a vector by definition)
-        idx = node.inputs[1]
+    for pos, idx in enumerate(cdata):
 
-        # `idx` must be equivalent to [0,1,...,shape[0] - 1] to qualify for
-        # this optimization
-        if isinstance(idx, Constant):
-            idx = idx.value
-            if len(idx) != length:
-                return False
-            if np.any(idx != np.arange(length)):
-                return False
-        elif idx.owner is not None and isinstance(idx.owner.op, ARange):
+        length_pos = shape_of[node.inputs[0]][pos]
+
+        if isinstance(idx.stop, (int, np.integer)):
+            length_pos_data = sys.maxsize
             try:
-                start, stop, step = map(
-                    lambda x: get_scalar_constant_value(x, only_process_constants=True),
-                    idx.owner.inputs,
+                length_pos_data = get_scalar_constant_value(
+                    length_pos, only_process_constants=True
                 )
             except NotScalarConstantError:
-                return False
+                pass
 
-            if start != 0:
+            if idx.stop < length_pos_data:
                 return False
-            if stop != length:
+        elif isinstance(idx.stop, Variable):
+            length_pos_shape_i = idx.stop
+            # length_pos is a tensor variable, but length_pos_shape_i
+            # is a scalar variable. We try to see if they represent
+            # the same underlying variable.
+            if length_pos_shape_i.owner and isinstance(
+                length_pos_shape_i.owner.op, ScalarFromTensor
+            ):
+                length_pos_shape_i = length_pos_shape_i.owner.inputs[0]
+            elif length_pos.owner and isinstance(length_pos.owner.op, TensorFromScalar):
+                length_pos = length_pos.owner.inputs[0]
+            else:
+                # We did not find underlying variables of the same type
                 return False
-            if step != 1:
+
+            # The type can be different: int32 vs int64. length_pos
+            # should always be int64 as that is what the shape
+            # tracker keep. Subtensor accept any scalar int{8,16,32,64}
+            # as index type.
+            assert str(length_pos.type.dtype) == "int64"
+            assert str(length_pos_shape_i.type.dtype) in [
+                "int8",
+                "int16",
+                "int32",
+                "int64",
+            ]
+
+            # length_pos_shape_i cannot be None
+            if length_pos_shape_i != length_pos:
                 return False
+        elif idx.stop is None:
+            continue
         else:
             return False
+
+    return [node.inputs[0]]
+
+
+@register_canonicalize
+@register_specialize
+@local_optimizer([AdvancedSubtensor1])
+def local_useless_AdvancedSubtensor1(fgraph, node):
+    """Remove `AdvancedSubtensor1` if it takes the full input.
+
+    In the `AdvancedSubtensor1` case, the full input is taken when the indices
+    are equivalent to ``arange(0, input.shape[0], 1)`` using either an explicit
+    list/vector or the `ARange` `Op`.
+
+    """
+    # This optimization needs ShapeOpt and fgraph.shape_feature
+    if not hasattr(fgraph, "shape_feature"):
+        return
+
+    shape_of = fgraph.shape_feature.shape_of
+
+    # get length of the indexed tensor along the first axis
+    try:
+        length = get_scalar_constant_value(
+            shape_of[node.inputs[0]][0], only_process_constants=True
+        )
+    except NotScalarConstantError:
+        return False
+
+    # get index (which must be a vector by definition)
+    idx = node.inputs[1]
+
+    # `idx` must be equivalent to [0,1,...,shape[0] - 1] to qualify for
+    # this optimization
+    if isinstance(idx, Constant):
+        idx = idx.value
+        if len(idx) != length:
+            return False
+        if np.any(idx != np.arange(length)):
+            return False
+    elif idx.owner is not None and isinstance(idx.owner.op, ARange):
+        try:
+            start, stop, step = map(
+                lambda x: get_scalar_constant_value(x, only_process_constants=True),
+                idx.owner.inputs,
+            )
+        except NotScalarConstantError:
+            return False
+
+        if start != 0:
+            return False
+        if stop != length:
+            return False
+        if step != 1:
+            return False
     else:
         return False
 
-    # We don't need to copy over any stacktrace here,
-    # because previous stacktrace should suffice.
     return [node.inputs[0]]