simple drop image valid case (tinygrad#6548)

* simple drop image valid case

started unit test, 530 -> 473 valids

* cleanup

.github/workflows/test.yml

@@ -199,7 +199,7 @@ jobs:
       - if: ${{ matrix.task == 'optimage' }}
         name: Test openpilot model compile and size
         run: |
-          PYTHONPATH="." DEBUG=2 ALLOWED_KERNEL_COUNT=208 ALLOWED_GATED_READ_IMAGE=530 FLOAT16=1 DEBUGCL=1 GPU=1 IMAGE=2 python examples/openpilot/compile2.py
+          PYTHONPATH="." DEBUG=2 ALLOWED_KERNEL_COUNT=208 ALLOWED_GATED_READ_IMAGE=473 FLOAT16=1 DEBUGCL=1 GPU=1 IMAGE=2 python examples/openpilot/compile2.py
           python -c 'import os; assert os.path.getsize("/tmp/output.thneed") < 100_000_000'
       - if: ${{ matrix.task == 'optimage' }}
         name: Test openpilot model correctness (float32)

test/unit/test_image_valid.py

@@ -0,0 +1,34 @@
+import unittest
+
+from tinygrad.codegen.uopgraph import linearize_uop, full_graph_rewrite
+from tinygrad.dtype import dtypes
+from tinygrad.ops import UOp, UOps, BinaryOps
+
+def render(image_shape, valid:UOp, idx:UOp) -> str:
+  uops = linearize_uop(full_graph_rewrite(UOp(UOps.LOAD, dtypes.float.vec(4), (
+    UOp(UOps.DEFINE_GLOBAL, dtypes.imagef(image_shape), arg=0),
+    idx,
+    UOp(UOps.VECTORIZE, dtypes.float.vec(4), src=(UOp.const(dtypes.float, 0),)*4),
+    valid
+  )).sink()))
+  from tinygrad.renderer.cstyle import OpenCLRenderer
+  class TestRenderer(OpenCLRenderer):
+    code_for_op = {**OpenCLRenderer().code_for_op, BinaryOps.IDIV: lambda a,b,dtype: f"({a}//{b})"}
+  fxn = TestRenderer().render("", uops)
+  return fxn.split("float4 val0 = ")[1].split(";")[0]
+
+def Variable(expr, nmax):
+  return UOp(UOps.SPECIAL, dtypes.int, (), (expr, nmax))
+
+class TestValidSimplification(unittest.TestCase):
+  def test_idx_lt_0(self):
+    # (idx1 * (-1) < 0) ? (..., idx1-1) : 0 can drop the valid
+    gidx0 = Variable("gidx0", 32)
+    gidx1 = Variable("gidx1", 32)
+    self.assertEqual(
+      render((10, 10, 4), (gidx1*(-1)).lt(0), UOp(UOps.VECTORIZE, dtypes.int.vec(2), (gidx0, gidx1-1))),
+      "read_imagef(data0, smp, (int2)(gidx0,(gidx1+(-1))))"
+    )
+
+if __name__ == '__main__':
+  unittest.main()

tinygrad/codegen/uopgraph.py

@@ -155,6 +155,16 @@ def fold_unrolled_divs(divs:UOp, c:UOp):
     seen_const.append(s0.src[1].arg)
   return ans if sorted(seen_const)==list(range(c.arg, c.arg+len(add_chain))) and ans is not None and (ans.vmin, ans.vmax)==(0, c.arg) else None
 
+# ***** image load valid simplification *****
+
+def simplify_valid_image_load(load:UOp, buf:UOp):
+  if not isinstance(buf.dtype, ImageDType) or len(load.src) < 4: return None
+  buf, idx, _, valid = load.src
+  if valid.op is UOps.ALU and valid.arg is BinaryOps.CMPLT:
+    if valid.src[1].arg == 0 and graph_rewrite(valid.src[0]*(-1)-1, constant_folder).key == idx.src[1].key:
+      # valid: A*(-1) < 0, idx: (..., A-1) -> okay to drop valid
+      return UOp(UOps.LOAD, dtype=load.dtype, src=(buf, idx))
+
 # ***** transcendental *****
 
 @functools.lru_cache(None)
@@ -494,6 +504,8 @@ def find_gate(x:UOp) -> Optional[UOp]:
   (UPat(UOps.STORE, name="root"), delete_redundant_gates),
   # late fixup of unfoldable image loads
   (UPat(UOps.LOAD, src=(UPat.var("buf"), UPat()), allow_any_len=True, name="load"), fix_unfoldable_image_load),
+  # image load valid simplification
+  (UPat(UOps.LOAD, src=(UPat.var("buf"), UPat()), allow_any_len=True, name="load"), simplify_valid_image_load),
 ])
 
 no_pyint = PatternMatcher([(UPat((UOps.CONST, UOps.VCONST, UOps.ALU, UOps.SPECIAL, UOps.RANGE, UOps.EXPAND, UOps.VECTORIZE), name="x"),