Dim complete_dyn_size, better combine ops

Fix #1410

returnn/tensor/_dim_extra.py

@@ -1089,18 +1089,17 @@ def _bin_op(a, b):
                     return a
                 if isinstance(b, _t.Tensor):
                     return b
+                raise Exception(f"Dim complete_dyn_size: bin_op: expect to get one Tensor, got {a} and {b}")
             if kind == "add":
-                return _relu(a + b)
+                return _relu(rf.combine_bc(a, "add", b))
             elif kind == "sub":
-                return _relu(a - b)
+                return _relu(rf.combine_bc(a, "sub", b))
             elif kind == "mul":
-                return a * b
+                return rf.combine_bc(a, "mul", b)
             elif kind in ("floordiv", "truediv"):  # truediv assumes there is no remainder
-                return a // b
+                return rf.combine_bc(a, "floordiv", b)
             elif kind == "ceildiv":
-                if isinstance(a, _t.Tensor):
-                    return rf.ceil_divide(a, b)
-                return -(-a // b)
+                return rf.combine_bc(a, "ceildiv", b)
             else:
                 raise ValueError("unknown op kind %r" % op.kind)
 
@@ -1148,17 +1147,14 @@ def _relu(a):
             if y is None:
                 y = x.copy(name=y_name)
                 continue
-            if x.dim_tags != y.dim_tags:
+            if tf:
                 common = _t.Tensor.get_common_data([x, y], allow_broadcast_all_sources=True)
                 x_ = x.copy_compatible_to_dims(common.dims) if x.dims else x
                 y_ = y.copy_compatible_to_dims(common.dims) if y.dims else y
                 y = common
-            else:
-                x_, y_ = x, y
-            if tf:
                 y.placeholder = _bin_op_tf(y_.placeholder, x_.placeholder)
             else:
-                y = _bin_op(y_, x_)
+                y = _bin_op(y, x)
         assert y, f"op {op}?"
         if self.dyn_size_ext:
             assert self.dyn_size_ext.dim_tags == y.dim_tags