Merge some loops in device_put since it's trivial to do so

PiperOrigin-RevId: 626546322

jax/_src/api.py

@@ -2439,7 +2439,7 @@ def make_jaxpr_f(*args, **kwargs):
 
 def _infer_src_sharding(src, x) -> Sharding | None:
   if src is not None:
-    return src
+    return src  # type: ignore
   if isinstance(x, array.ArrayImpl):
     return x.sharding
   elif isinstance(x, core.Tracer):
@@ -2493,21 +2493,20 @@ def device_put(
          isinstance(device, (xc.Device, Sharding, TransferToMemoryKind))) and
         (src is None or
          isinstance(src, (xc.Device, Sharding, TransferToMemoryKind)))):
-      for leaf in tree_leaves(x):
-        _check_sharding(shaped_abstractify(leaf), s=device)
-      return tree_map(
-          lambda y: dispatch.device_put_p.bind(
-              y, device=device, src=_infer_src_sharding(src, y)), x)
+      def _map(y):
+        _check_sharding(shaped_abstractify(y), s=device)
+        return dispatch.device_put_p.bind(
+            y, device=device, src=_infer_src_sharding(src, y))
+      return tree_map(_map, x)
 
     x_flat, treedef = tree_flatten(x)
     device_flat = flatten_axes("device_put device", treedef, device)
     src_flat = flatten_axes("device_put source", treedef, src)
-    for x_leaf, device_leaf in zip(x_flat, device_flat):
-      _check_sharding(shaped_abstractify(x_leaf), device_leaf)
-    out_flat = [
-        dispatch.device_put_p.bind(xf, device=d, src=_infer_src_sharding(s, xf))
-        for xf, d, s in zip(x_flat, device_flat, src_flat)
-    ]
+    out_flat = []
+    for xf, d, s in zip(x_flat, device_flat, src_flat):
+      _check_sharding(shaped_abstractify(xf), d)
+      out_flat.append(dispatch.device_put_p.bind(
+          xf, device=d, src=_infer_src_sharding(s, xf)))
     return tree_unflatten(treedef, out_flat)