From 277433259eb71b5fc3d6d5cc33c5a1be1458e9fa Mon Sep 17 00:00:00 2001
From: chenyu <chenyu@fastmail.com>
Date: Fri, 31 Jul 2026 14:38:38 -0400
Subject: [PATCH] fix sym_infer for CAST (#17338)

---
 test/null/test_uop_symbolic.py | 4 ++++
 tinygrad/uop/render.py         | 2 ++
 2 files changed, 6 insertions(+)

diff --git a/test/null/test_uop_symbolic.py b/test/null/test_uop_symbolic.py
index 8678d762a0..183175ef09 100644
--- a/test/null/test_uop_symbolic.py
+++ b/test/null/test_uop_symbolic.py
@@ -1202,6 +1202,10 @@ class TestSymInfer(unittest.TestCase):
     # floor: 1 % -1000 = -999, 1 // -1000 = -1
     assert sym_infer(a%b, var_vals) == -999
     assert sym_infer(a//b, var_vals) == -1
+  def test_sym_infer_with_cast(self):
+    a = Variable("a", 0, 100, dtypes.int)
+    assert sym_infer(a.cast(dtypes.long) + 1, {a.expr: 5}) == 6
+    assert sym_infer(a.cast(dtypes.float) * 0.5, {a.expr: 5}) == 2.5
   def test_sym_infer_with_bitcast(self):
     a = Variable("a", 1, 10, dtypes.int)
     expr = ((a.bitcast(dtypes.uint) << UOp.const(1)).bitcast(dtypes.int) + 2)
diff --git a/tinygrad/uop/render.py b/tinygrad/uop/render.py
index b88c97f13b..97ebe79db4 100644
--- a/tinygrad/uop/render.py
+++ b/tinygrad/uop/render.py
@@ -58,6 +58,8 @@ renderer_infer = PatternMatcher([
   (UPat(Ops.CDIV, name="x"), lambda ctx,x: f"cdiv({ctx[x.src[0]]}, {ctx[x.src[1]]})"),
   (UPat(Ops.FLOORMOD, name="x"), lambda ctx,x: f"floormod({ctx[x.src[0]]}, {ctx[x.src[1]]})"),
   (UPat(Ops.FLOORDIV, name="x"), lambda ctx,x: f"floordiv({ctx[x.src[0]]}, {ctx[x.src[1]]})"),
+  (UPat(Ops.CAST, name="x"),
+    lambda ctx,x: f"{'float' if dtypes.is_float(x.dtype) else 'bool' if x.dtype is dtypes.bool else 'int'}({ctx[x.src[0]]})"),
   (UPat(Ops.BITCAST, name="x"), lambda ctx,x: f"bitcast({ctx[x.src[0]]}, {x.src[0].dtype!r}, {x.dtype!r})"),
 ]) + renderer