From aecd51f54a6cebfa2de53ff084a87e7a15f38905 Mon Sep 17 00:00:00 2001
From: George Hotz <geohot@gmail.com>
Date: Mon, 20 Oct 2025 11:17:00 +0800
Subject: [PATCH] start multioutput support

---
 test/test_schedule.py         |  8 ++++++++
 tinygrad/helpers.py           |  1 +
 tinygrad/schedule/indexing.py | 23 +++++++++++++++++++++++
 tinygrad/schedule/rangeify.py |  3 ++-
 4 files changed, 34 insertions(+), 1 deletion(-)

diff --git a/test/test_schedule.py b/test/test_schedule.py
index f6f12f182c..b41fe73764 100644
--- a/test/test_schedule.py
+++ b/test/test_schedule.py
@@ -2414,5 +2414,13 @@ class TestUOpBecome(unittest.TestCase):
     b.shrink(((0,4),)).assign(a_view).realize()
     self.assertListEqual(b.tolist(), [0.0, 0.0, 0.0, 0.0, 1.0, 1.0, 1.0, 1.0, 1.0, 1.0, 1.0, 1.0, 1.0, 1.0, 1.0, 1.0])
 
+class TestScheduleMultioutput(unittest.TestCase):
+  def test_simplest_multioutput(self):
+    a = Tensor.ones(256, 256).contiguous().realize()
+    r = a.sum(axis=1)
+    b = r+1
+    c = r+2
+    check_schedule([b, c], 1)
+
 if __name__ == '__main__':
   unittest.main(verbosity=2)
diff --git a/tinygrad/helpers.py b/tinygrad/helpers.py
index 1e39715692..9cacc65b4b 100644
--- a/tinygrad/helpers.py
+++ b/tinygrad/helpers.py
@@ -171,6 +171,7 @@ SPEC = ContextVar("SPEC", 0)
 IGNORE_OOB = ContextVar("IGNORE_OOB", 1)
 PCONTIG = ContextVar("PCONTIG", 0)  # partial contiguous in rangeify
 REAL_SUBSTITUTE = ContextVar("REAL_SUBSTITUTE", 0)
+DEBUG_RANGEIFY = ContextVar("DEBUG_RANGEIFY", 0)
 
 @dataclass(frozen=True)
 class Metadata:
diff --git a/tinygrad/schedule/indexing.py b/tinygrad/schedule/indexing.py
index d4b048a823..f5a7a999db 100644
--- a/tinygrad/schedule/indexing.py
+++ b/tinygrad/schedule/indexing.py
@@ -141,6 +141,7 @@ def apply_movement_op(op:Ops, in_shape:tuple[sint,...], arg:tuple, rngs:tuple[UO
 
 @profile_matches
 def run_rangeify(tsink:UOp, debug:bool=False) -> tuple[UOp, IndexingContext]:
+  if debug: print("**************************")
   rctx = IndexingContext()
 
   # get ops to realize
@@ -252,5 +253,27 @@ def run_rangeify(tsink:UOp, debug:bool=False) -> tuple[UOp, IndexingContext]:
     # assign to the range map. rngs are the input ranges, out_rngs are the output ranges, from the x op.
     rctx.range_map[x] = (rngs, out_rngs)
 
+  # second forward pass to fuse children
+  replaced_ranges = {}
+  for x in tsink.toposort():
+    if x not in rctx.realize_map: continue
+    out_rngs = rctx.range_map[x][1]
+    _realize_axis = rctx.realize_map[x]
+    consumers = [rctx.range_map[u][0] for u in consumer_map[x] if u in rctx.range_map]
+    if len(consumers) < 2: continue
+    assert all(len(out_rngs) == len(rr) for rr in consumers)
+    for i,c in enumerate(zip(*consumers)):
+      out_rng = out_rngs[i]
+      # check if they are all simple ranges
+      if not all(y.op is Ops.RANGE and y.vmax == out_rng.vmax for y in c): continue
+      for r in c: replaced_ranges[r] = out_rngs[i]
+      _realize_axis.remove(i)
+    if len(_realize_axis) == 0: del rctx.realize_map[x]
+    else: rctx.realize_map[x] = _realize_axis
+
+  # do all the replaces
+  for k,(v0,v1) in rctx.range_map.items():
+    rctx.range_map[k] = (tuple(x.substitute(replaced_ranges) for x in v0), tuple(x.substitute(replaced_ranges) for x in v1))
+
   tsink = graph_rewrite(tsink, pm_apply_rangeify, ctx=rctx, bottom_up=True, name="apply rangeify")
   return tsink, rctx
diff --git a/tinygrad/schedule/rangeify.py b/tinygrad/schedule/rangeify.py
index c058a255bb..495922758c 100644
--- a/tinygrad/schedule/rangeify.py
+++ b/tinygrad/schedule/rangeify.py
@@ -5,6 +5,7 @@ from tinygrad.uop.ops import PatternMatcher, UPat, Ops, UOp, resolve, GroupOp, _
 from tinygrad.uop.ops import track_rewrites, graph_rewrite, identity_element, sint, AxisType
 from tinygrad.uop.symbolic import symbolic_flat
 from tinygrad.helpers import argsort, prod, all_same, pluralize, getenv, flatten, dedup, all_int, DEBUG, SPLIT_REDUCEOP, Metadata, REAL_SUBSTITUTE
+from tinygrad.helpers import DEBUG_RANGEIFY
 from tinygrad.codegen.simplify import pm_flatten_range, pm_reduce_unparented
 from tinygrad.codegen.opt import Opt
 from tinygrad.schedule.indexing import run_rangeify, BufferizeOpts, ALWAYS_CONTIGUOUS, IndexingContext, apply_movement_op
@@ -498,7 +499,7 @@ def get_rangeify_map(sink:UOp) -> dict[UOp, UOp]:
   tsink = graph_rewrite(tsink, earliest_rewrites+replace_contiguous, ctx={}, name="earliest rewrites")
 
   # convert movement ops to ranges
-  tsink, rctx = run_rangeify(tsink, getenv("DEBUG_RANGEIFY", 0))
+  tsink, rctx = run_rangeify(tsink, DEBUG_RANGEIFY)
 
   # NOTE: sym (vs symbolic_simple) breaks things here because ranges with len 1 aren't handled right
   tsink = graph_rewrite(tsink, symbolic_flat+pm_reduce_unparented, name="symbolic")  # this supports const folding