Don't apply local_add_neg_to_sub rewrite if negative variabe is a constant

Author: ricardoV94

pytensor/tensor/rewriting/math.py

@@ -1824,15 +1824,6 @@ def local_add_neg_to_sub(fgraph, node):
                     new_out = sub(first, pre_neg)
                     return [new_out]
 
-            # Check if it is a negative constant
-            if (
-                isinstance(second, TensorConstant)
-                and second.unique_value is not None
-                and second.unique_value < 0
-            ):
-                new_out = sub(first, np.abs(second.data))
-                return [new_out]
-
 
 @register_canonicalize
 @node_rewriter([mul])

tests/tensor/rewriting/test_math.py

@@ -4440,25 +4440,6 @@ def test_local_add_neg_to_sub(first_negative):
     assert np.allclose(f(x_test, y_test), exp)
 
 
-@pytest.mark.parametrize("const_left", (True, False))
-def test_local_add_neg_to_sub_const(const_left):
-    x = vector("x")
-    const = np.full((3, 2), 5.0)
-    out = -const + x if const_left else x + (-const)
-
-    f = function([x], out, mode=Mode("py"))
-
-    nodes = [
-        node.op
-        for node in f.maker.fgraph.toposort()
-        if not isinstance(node.op, DimShuffle | Alloc)
-    ]
-    assert nodes == [pt.sub]
-
-    x_test = np.array([3, 4], dtype=config.floatX)
-    assert np.allclose(f(x_test), x_test + (-const))
-
-
 def test_log1mexp_stabilization():
     mode = Mode("py").including("stabilize")