carrot/tinygrad_repo/test/external/fuzz_fast_idiv.py

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import random
from z3 import Int, Solver, sat
from tinygrad import dtypes, Device
from tinygrad.uop.ops import UOp, Ops, UPat, graph_rewrite, PatternMatcher
from tinygrad.codegen.devectorizer import fast_idiv
random.seed(42)
z3_renderer = PatternMatcher([
(UPat((Ops.DEFINE_VAR, Ops.SPECIAL), name="x"), lambda x: UOp(Ops.NOOP, arg=x.arg[0])),
# Because fast_idiv only works for non-negative integers we can emulate machine arithmetic with modulo operations.
(UPat(Ops.SHR, src=UPat(Ops.NOOP), name="x"), lambda x: UOp(Ops.NOOP, arg=f"(({x.src[0].arg}/(2**{x.src[1].arg}))%{dtypes.max(x.dtype)+1})")),
(UPat(Ops.MUL, src=UPat(Ops.NOOP), name="x"), lambda x: UOp(Ops.NOOP, arg=f"(({x.src[0].arg}*{x.src[1].arg})%{dtypes.max(x.dtype)+1})")),
(UPat((Ops.CONST, Ops.VCONST), name="x"), lambda x: UOp(Ops.NOOP, arg=str(x.arg))),
(UPat(Ops.CAST, src=UPat(Ops.NOOP), name="x"), lambda x: UOp(Ops.NOOP, arg=f"{x.src[0].arg}")),
])
def render(self) -> str:
ret = graph_rewrite(self.simplify(), z3_renderer)
return ret.arg if ret.op is Ops.NOOP else str(ret)
if __name__ == "__main__":
x = Int('x')
for _ in range(10_000):
dt = random.choice(dtypes.ints)
u = UOp(Ops.DEFINE_VAR, dt, arg=('x', 0, random.randint(1, dtypes.max(dt))), src=())
d = random.randint(1, max(1, u.arg[2]))
expr = fast_idiv(Device[Device.DEFAULT].renderer, u, d)
if expr is None: continue
solver = Solver()
solver.add(x>=u.arg[1], x<=u.arg[2])
if solver.check(eval(render(expr)) != x/d) == sat:
assert False, f"Failed: {render(expr)} != x//{d} at x={solver.model()[x]}\nx={u}\nd={d}"