broadcast_to just works thanks to expand (#191)

Author: kshitij12345

functorch/csrc/BatchRulesStopDecomposition.cpp

@@ -159,7 +159,6 @@ TORCH_LIBRARY_IMPL(aten, FT_BATCHED_KEY, m) {
   STOP_DECOMPOSE(blackman_window);
   STOP_DECOMPOSE(blackman_window.periodic);
   STOP_DECOMPOSE(block_diag);
-  STOP_DECOMPOSE(broadcast_to);
   STOP_DECOMPOSE(can_cast);
   STOP_DECOMPOSE(cartesian_prod);
   STOP_DECOMPOSE(cat.names);

test/test_ops.py

@@ -505,7 +505,6 @@ def test():
     @ops(functorch_lagging_op_db + additional_op_db, allowed_dtypes=(torch.float,))
     @skipOps('TestOperators', 'test_vjpvmap', vjp_fail.union({
         xfail('__getitem__'),
-        xfail('broadcast_to'),
         xfail('clamp', ''),
         xfail('dsplit'),
         xfail('fill_'),

test/test_vmap.py

@@ -2973,7 +2973,6 @@ class TestVmapOperatorsOpInfo(TestCase):
     @ops(functorch_lagging_op_db + additional_op_db, allowed_dtypes=(torch.float,))
     @skipOps('TestVmapOperatorsOpInfo', 'test_vmap_exhaustive', {
         # These are ops that we can't generate fallbacks for
-        xfail('broadcast_to'),
         xfail('dsplit'),
         xfail('fill_'),
         xfail('gradient'),
@@ -3023,7 +3022,6 @@ def test_vmap_exhaustive(self, device, dtype, op):
     @ops(functorch_lagging_op_db + additional_op_db, allowed_dtypes=(torch.float,))
     @skipOps('TestVmapOperatorsOpInfo', 'test_op_has_batch_rule', {
         # xfail('__getitem__'),
-        xfail('broadcast_to'),
         xfail('cdist'),
         xfail('complex'),
         xfail('copysign'),