I get the following error when executing simple code targeted at opencl. This is after I have installed a new opencl platform called pocl. Furthermore this error occurs even I if just use llvm target and cpu I cant figure out why ?.

This is the code that produced the error.

```
import tvm
from tvm import te
import numpy as np
n = te.var("n")
A = te.placeholder((n,),name = 'A')
B = te.placeholder((n,),name = 'B')
C = te.compute(A.shape,lambda i: A[i] + B[i], name = 'C')
s = te.create_schedule(C.op)
bx, tx = s[C].split(C.op.axis[0], factor = 64)
s[C].bind(bx, te.thread_axis("blockIdx.x"))
s[C].bind(tx, te.thread_axis("threadIdx.x"))
fadd_cl = tvm.build(s, [A,B,C], target= 'opencl' , name = "myadd")
ctx = tvm.opencl()
n = 1024
a = tvm.nd.array(np.random.uniform(size=n).astype(A.dtype), ctx)
b = tvm.nd.array(np.random.uniform(size=n).astype(B.dtype), ctx)
c = tvm.nd.array(np.zeros(n, dtype=C.dtype), ctx)
fadd_cl(a,b,c)
np.testing.assert_allclose(c.asnumpy(), a.asnumpy() + b.asnumpy())
```