[pallas:gpu] Implement get and swap using load and `masked_swap…

…` lowering rules.

PiperOrigin-RevId: 573146382

jax/_src/pallas/triton/lowering.py

@@ -719,30 +719,34 @@ def _pack_indices(non_slice_idx, indexed_dims):
 def _get_lowering_rule(
     ctx: TritonLoweringRuleContext, ptr, *non_slice_idx, indexed_dims
 ):
-  ref_block_info, *_ = ctx.block_infos
-  idx = _pack_indices(non_slice_idx, indexed_dims)
-  avals_in = ctx.avals_in
-  idx_avals = _pack_indices(avals_in[1:], indexed_dims)
   if not isinstance(ptr.type, tl.pointer_type):
-    assert len(avals_in) == 1
+    assert not non_slice_idx
     return ptr
+
+  ref_aval, *idx_avals = ctx.avals_in
+  idx_avals = _pack_indices(idx_avals, indexed_dims)
   if non_slice_idx:
     (int_indexer_shape,) = {
         i.shape for i in idx_avals if not isinstance(i, slice)
     }
   else:
     int_indexer_shape = ()
+
+  idx = _pack_indices(non_slice_idx, indexed_dims)
   idx = tuple(
       primitives.Slice.from_slice(slc, s) if isinstance(slc, slice) else slc
-      for s, slc in zip(avals_in[0].shape, idx)
+      for s, slc in zip(ref_aval.shape, idx)
   )
-  idx = primitives.NDIndexer(idx, avals_in[0].shape, int_indexer_shape)
-  ptr = _compute_pointers_from_indices(
-      ptr, ref_block_info, idx, avals_in[0].shape, ctx.builder
+  idx = NDIndexer(idx, ref_aval.shape, int_indexer_shape)
+  args_flat, args_tree = tree_util.tree_flatten((ptr, idx, None, None))
+  return _masked_load_lowering_rule(
+      ctx,
+      *args_flat,
+      args_tree=args_tree,
+      eviction_policy=None,
+      cache_modifier=None,
+      is_volatile=False,
   )
-  val = tl.load(ptr, _builder=ctx.builder)
-  # `tl.load` of a `*int1` returns a tensor with type `int8`, so fix the type.
-  return val.to(ptr.dtype.element_ty, _builder=ctx.builder)
 
 
 triton_lowering_rules[sp.get_p] = _get_lowering_rule
@@ -782,28 +786,25 @@ def _masked_load_lowering_rule(
 def _swap_lowering_rule(
     ctx: TritonLoweringRuleContext, ptr, value, *non_slice_idx, indexed_dims
 ):
-  ref_block_info, *_ = ctx.block_infos
-  avals_in = ctx.avals_in
-  idx = _pack_indices(non_slice_idx, indexed_dims)
-  idx_avals = _pack_indices(avals_in[2:], indexed_dims)
+  ref_aval, _, *idx_avals = ctx.avals_in
+  idx_avals = _pack_indices(idx_avals, indexed_dims)
   if non_slice_idx:
     (int_indexer_shape,) = {
         i.shape for i in idx_avals if not isinstance(i, slice)
     }
   else:
     int_indexer_shape = ()
+
+  idx = _pack_indices(non_slice_idx, indexed_dims)
   idx = tuple(
       primitives.Slice.from_slice(slc, s) if isinstance(slc, slice) else slc
-      for s, slc in zip(avals_in[0].shape, idx)
+      for s, slc in zip(ref_aval.shape, idx)
   )
-  idx = primitives.NDIndexer(idx, avals_in[0].shape, int_indexer_shape)
-  ptr = _compute_pointers_from_indices(
-      ptr, ref_block_info, idx, avals_in[0].shape, ctx.builder
+  idx = NDIndexer(idx, ref_aval.shape, int_indexer_shape)
+  args_flat, args_tree = tree_util.tree_flatten((ptr, idx, value, None))
+  return _masked_swap_lowering_rule(
+      ctx, *args_flat, args_tree=args_tree, eviction_policy=None
   )
-  mask = None
-  old_value = tl.load(ptr, mask=mask, _builder=ctx.builder)
-  tl.store(ptr, value, mask=mask, _builder=ctx.builder)
-  return old_value
 
 
 triton_lowering_rules[sp.swap_p] = _swap_lowering_rule