TH3CHARLie opened a new issue, #15911:
URL: https://github.com/apache/tvm/issues/15911
### Expected behavior
program scheduled with `reverse_compute_at` should generate the same answer.
### Actual behavior
wrong result, seems like some part of array is not computed
### Environment
ubuntu 20.04, tvm main branch
### Steps to reproduce
A program to reproduce:
```python
import tvm
from tvm.ir.module import IRModule
from tvm.script import tir as T
import numpy as np
from tvm import te
import tvm.testing
# compute reference
tgt = tvm.target.Target(target="llvm", host="llvm")
dev = tvm.device(tgt.kind.name, 0)
n = te.var("n")
p = te.const(32, "int32")
A = te.placeholder((n,), dtype="float32", name="A")
B = te.placeholder((n,), dtype="float32", name="B")
C = te.compute(A.shape, lambda i: A[i] + B[i], name="C")
D = te.compute(A.shape, lambda i: C[i] + C[i], name="D")
E = te.compute(A.shape, lambda i: D[i] + A[i], name="E")
func = te.create_prim_func([A, B, E])
ir_mod = IRModule({"main": func})
mod = tvm.build(ir_mod, tgt)
n = 1024
np_a = np.arange(n).astype(A.dtype)
np_b = np.arange(n).astype(B.dtype)
ref_a = tvm.nd.array(np_a, dev)
ref_b = tvm.nd.array(np_b, dev)
ref_e = tvm.nd.array(np.zeros(n, dtype=E.dtype), dev)
mod(ref_a, ref_b, ref_e)
# apply the schedule and compute the results
schedule = tvm.tir.Schedule(ir_mod)
block_d = schedule.get_block("D")
i, = schedule.get_loops(block_d)
i_0, i_1 = schedule.split(i, factors=[None, 16])
schedule.reorder(i_1, i_0)
schedule.add_unit_loop(block_d)
block_c = schedule.get_block("C")
schedule.compute_inline(block_c)
block_e = schedule.get_block("E")
schedule.reverse_compute_at(block_e, i_1)
ir_mod = schedule.mod
mod = tvm.build(ir_mod, tgt)
tgt_e = tvm.nd.array(np.zeros(n, dtype=E.dtype), dev)
mod(ref_a, ref_b, tgt_e)
tvm.testing.assert_allclose(ref_e.numpy(), tgt_e.numpy(), rtol=1e-5)
```
Essentially the program computes A+B+A+B+A so we should expect the final
output being 5 times of A, clearly `tgt_e` is not the case.
### Triage
Please refer to the list of label tags
[here](https://github.com/apache/tvm/wiki/Issue-Triage-Labels) to find the
relevant tags and add them below in a bullet format (example below).
* needs-triage
* tir:schedule
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