diff --git a/tinygrad/codegen/late/devectorizer.py b/tinygrad/codegen/late/devectorizer.py
index 7f866cd9c8f25..230d5e357c372 100644
--- a/tinygrad/codegen/late/devectorizer.py
+++ b/tinygrad/codegen/late/devectorizer.py
@@ -1,7 +1,7 @@
 from typing import Any, cast
 import functools, itertools
 from collections import defaultdict
-from dataclasses import dataclass, field
+from dataclasses import dataclass
 from tinygrad.dtype import dtypes, ImageDType, DType, AddrSpace, Invalid, PtrDType
 from tinygrad.uop.ops import UOp, Ops, UPat, PatternMatcher, GroupOp, identity_element
 from tinygrad.uop.symbolic import uop_given_valid, parse_valid, invalid_gate
@@ -308,8 +308,6 @@ def no_vectorized_index_broadcast(buf:UOp, cast:UOp, bcast:UOp, idx:UOp):
 @dataclass
 class ReduceContext:
   acc_num: int = 0
-  # track ENDs by range for merging parallel reduces
-  range_to_ends: dict[tuple[UOp, ...], list[UOp]] = field(default_factory=dict)
 
 def horizontal_reduce(inp:UOp, out_dtype:DType) -> list[UOp]:
   # if this has a horizontal reduction component, do that first
@@ -335,13 +333,15 @@ def reduce_to_acc(ctx:ReduceContext, red:UOp):
     ctx.acc_num += 1
   ret = functools.reduce(lambda x,y: x.alu(red.arg, y), lst)
   if len(reduce_range) == 0: return ret
-  end = acc.index(UOp.const(dtypes.int, 0)).store(ret).end(*reduce_range)
-  ctx.range_to_ends.setdefault(reduce_range, []).append(end)
+  end = acc.index(UOp.const(dtypes.int, 0)).store(ret).end(*reduce_range).rtag("mergeable")
   return acc.after(end).index(UOp.const(dtypes.int, 0))
 
 def merge_reduce_ends(ctx:ReduceContext, sink:UOp):
-  # merge ENDs that share the same range
-  subs = {e: UOp.group(*(e.src[0] for e in ends)).end(*r) for r, ends in ctx.range_to_ends.items() if len(ends) > 1 for e in ends}
+  # merge ENDs that share the same range (only those created by reduce_to_acc)
+  range_to_ends: dict[tuple[UOp, ...], list[UOp]] = {}
+  for u in sink.backward_slice:
+    if u.op is Ops.END and u.tag == "mergeable": range_to_ends.setdefault(u.src[1:], []).append(u)
+  subs = {e: UOp.group(*(e.src[0] for e in ends)).end(*r) for r, ends in range_to_ends.items() if len(ends) > 1 for e in ends}
   return sink.substitute(subs) if subs else None
 
 pm_reduce = PatternMatcher([