[Bug] TVMScript fails with LetStmt #13892
Description
Hi there,
I encountered an error that when generating TVMScript with LetStmt, the generated script cannot be parsed if the var in LetStmt appears the first time in the IR.
import tvm
from tvm.script import tir as T
from tvm import te
def test_let_roundtrip():
x = te.var("x")
y = te.var("y")
let0 = tvm.tir.LetStmt(x, 0, tvm.tir.Evaluate(0))
let1 = tvm.tir.LetStmt(y, 1, tvm.tir.Evaluate(0))
body = tvm.tir.SeqStmt([let0, let1])
func = tvm.tir.PrimFunc([], body)
print(func.script())
# Parse fail
roundtrip = tvm.script.from_source(func.script())
tvm.ir.assert_structural_equal(func, roundtrip, True)
The above case generates TVMScript as below
@T.prim_func
def main():
with T.let(x, 0):
T.evaluate(0)
y: T.int32 = 1
T.evaluate(0)
But when parsing this TVMScript, it reports an error that 'x' is an undefined variable so that the parse failed. The TVMScript with LetStmt is not round-trippable in this case.
test_let_roundtrip.py::test_let_roundtrip # from tvm.script import tir as T
@T.prim_func
def main():
with T.let(x, 0):
T.evaluate(0)
y: T.int32 = 1
T.evaluate(0)
error: Undefined variable: x
--> <str>:5:16
|
5 | with T.let(x, 0):
| ^
FAILED
For the semantic of LetStmt, I think'x' should be identified as a definition, the script should be parsed successly.
Please let me know if there is any confusion, thanks very much!
Environment
latest TVM mainline