Remove superfluous test value warning in Elemwise fusion rewrite

aesara/tensor/basic_opt.py

@@ -16,6 +16,7 @@ from aesara import compile
 from aesara.compile.ops import ViewOp
 from aesara.configdefaults import config
 from aesara.graph.basic import (
+    Apply,
     Constant,
     Variable,
     ancestors,
@@ -24,7 +25,7 @@ from aesara.graph.basic import (
 )
 from aesara.graph.features import AlreadyThere, Feature, ReplaceValidate
 from aesara.graph.fg import FunctionGraph
-from aesara.graph.op import get_test_value
+from aesara.graph.op import compute_test_value, get_test_value
 from aesara.graph.opt import (
     GlobalOptimizer,
     OpRemove,
@@ -3003,7 +3004,7 @@ def local_elemwise_fusion_op(op_class, max_input_fct=lambda node: 32, maker=None
         fused = False
 
         for i in node.inputs:
-            do_fusion = False
+            scalar_node: Optional[Apply] = None
             # Will store inputs of the fused node that are not currently inputs
             # of the node we want to create (to avoid duplicating inputs).
             tmp_input = []
@@ -3034,36 +3035,45 @@ def local_elemwise_fusion_op(op_class, max_input_fct=lambda node: 32, maker=None
                             tmp_s_input.append(tmp_scalar[tmp_input.index(ii)])
                         else:
                             tmp = aes.get_scalar_type(ii.type.dtype).make_variable()
+
                             try:
                                 tv = get_test_value(ii)
-                                if tv.size > 0:
-                                    tmp.tag.test_value = tv.flatten()[0]
-                                else:
-                                    _logger.warning(
-                                        "Cannot construct a scalar test value"
-                                        " from a test value with no size: {}".format(ii)
-                                    )
-                            except TestValueError:
+                                # Sometimes the original inputs have
+                                # zero-valued shapes in some dimensions, which
+                                # implies that this whole scalar thing doesn't
+                                # make sense (i.e. we're asking for the scalar
+                                # value of an entry in a zero-dimensional
+                                # array).
+                                # This will eventually lead to an error in the
+                                # `compute_test_value` call below when/if
+                                # `config.compute_test_value_opt` is enabled
+                                # (for debugging, more or less)
+                                tmp.tag.test_value = tv.item()
+                            except (TestValueError, ValueError):
                                 pass
 
                             tmp_s_input.append(tmp)
                             tmp_input.append(ii)
                             tmp_scalar.append(tmp_s_input[-1])
 
-                    s_op = i.owner.op.scalar_op(*tmp_s_input, return_list=True)
+                    # Use the `Op.make_node` interface in case `Op.__call__`
+                    # has been customized
+                    scalar_node = i.owner.op.scalar_op.make_node(*tmp_s_input)
+
+                    if config.compute_test_value_opt != "off":
+                        # This is required because `Op.make_node` won't do it
+                        compute_test_value(scalar_node)
 
                     # If the scalar_op doesn't have a C implementation, we skip
                     # its fusion to allow fusion of the other ops
                     i.owner.op.scalar_op.c_code(
-                        s_op[0].owner,
+                        scalar_node,
                         "test_presence_of_c_code",
                         ["x" for x in i.owner.inputs],
                         ["z" for z in i.owner.outputs],
                         {"fail": "%(fail)s"},
                     )
 
-                    do_fusion = True
-
                 except (NotImplementedError, MethodNotDefined):
                     _logger.warning(
                         (
@@ -3073,7 +3083,7 @@ def local_elemwise_fusion_op(op_class, max_input_fct=lambda node: 32, maker=None
                             "loop fusion."
                         )
                     )
-                    do_fusion = False
+                    scalar_node = None
 
             # Compute the number of inputs in case we fuse this input.
             # We subtract 1 because we replace the existing input with the new
@@ -3089,12 +3099,12 @@ def local_elemwise_fusion_op(op_class, max_input_fct=lambda node: 32, maker=None
                 if x in node.inputs:
                     new_nb_input_ -= 1
 
-            if do_fusion and (new_nb_input_ <= max_nb_input):
+            if scalar_node and (new_nb_input_ <= max_nb_input):
                 fused = True
                 new_nb_input = new_nb_input_
                 inputs.extend(tmp_input)
                 s_inputs.extend(tmp_scalar)
-                s_g.extend(s_op)
+                s_g.extend(scalar_node.outputs)
             else:
                 # We must support the case where the same variable appears many
                 # times within the inputs
@@ -3102,13 +3112,14 @@ def local_elemwise_fusion_op(op_class, max_input_fct=lambda node: 32, maker=None
                     s = s_inputs[inputs.index(i)]
                 else:
                     s = aes.get_scalar_type(i.type.dtype).make_variable()
-                    try:
-                        if config.compute_test_value != "off":
+                    if config.compute_test_value_opt != "off":
+                        try:
                             v = get_test_value(i)
-                            if v.size > 0:
-                                s.tag.test_value = v.flatten()[0]
-                    except TestValueError:
-                        pass
+                            # See the zero-dimensional test value situation
+                            # described above.
+                            s.tag.test_value = v.item()
+                        except (TestValueError, ValueError):
+                            pass
 
                     inputs.append(i)
                     s_inputs.append(s)
@@ -3157,7 +3168,8 @@ your code will run correctly, but may be slower."""
 
         if len(new_node.inputs) > max_nb_input:
             _logger.warning(
-                "loop fusion failed because Op would exceed" " kernel argument limit."
+                "Loop fusion failed because the resulting node "
+                "would exceed the kernel argument limit."
             )
             return False
 

tests/tensor/test_basic_opt.py

+import contextlib
 import copy
 
 import numpy as np
@@ -22,6 +23,7 @@ from aesara.graph.type import Type
 from aesara.misc.safe_asarray import _asarray
 from aesara.printing import pprint
 from aesara.raise_op import Assert, CheckAndRaise
+from aesara.scalar.basic import Composite
 from aesara.tensor.basic import (
     Alloc,
     Join,
@@ -1152,6 +1154,54 @@ class TestFusion:
             for n in f.maker.fgraph.toposort()
         )
 
+    @pytest.mark.parametrize("test_value", [np.c_[[1.0]], np.c_[[]]])
+    def test_test_values(self, test_value):
+        """Make sure that `local_elemwise_fusion_op` uses test values correctly when they have zero dimensions.
+
+        The test values we're talking about are the ones used when C implementations
+        are checked.
+
+        """
+
+        opts = OptimizationQuery(
+            include=[
+                "local_elemwise_fusion",
+                "composite_elemwise_fusion",
+                "canonicalize",
+            ],
+            exclude=["cxx_only", "BlasOpt"],
+        )
+
+        mode = Mode(self.mode.linker, opts)
+
+        x, y, z = dmatrices("xyz")
+
+        x.tag.test_value = test_value
+        y.tag.test_value = test_value
+        z.tag.test_value = test_value
+
+        if test_value.size == 0:
+            cm = pytest.raises(ValueError)
+        else:
+            cm = contextlib.suppress()
+
+        with config.change_flags(
+            compute_test_value="raise", compute_test_value_opt="raise"
+        ):
+            out = x * y + z
+            with cm:
+                f = function([x, y, z], out, mode=mode)
+
+        if test_value.size != 0:
+            # Confirm that the fusion happened
+            assert isinstance(f.maker.fgraph.outputs[0].owner.op.scalar_op, Composite)
+            assert len(f.maker.fgraph.toposort()) == 1
+
+            x_c, y_c, z_c = f.maker.fgraph.outputs[0].owner.inputs
+            assert np.array_equal(
+                f.maker.fgraph.outputs[0].tag.test_value, np.c_[[2.0]]
+            )
+
 
 class TimesN(aes.basic.UnaryScalarOp):
     """