Compiler crash [15.1, Ubuntu]

The attached kernel crashes the Intel OpenCL Runtime 15.1 (Ubuntu):

Both operands to ICmp instruction are not of the same type!
  %37 = icmp slt i32 %35, i64 0
Both operands to a binary operator are not of the same type!
  %47 = add i32 %36, i64 1
Both operands to a binary operator are not of the same type!
  %48 = add i32 %47, i64 %24
Both operands to ICmp instruction are not of the same type!
  %51 = icmp slt i64 %44, i32 %50
Both operands to ICmp instruction are not of the same type!
  %52 = icmp slt i32 %50, i64 0
Invalid operands for select instruction!
  %54 = select i1 %53, i64 %44, i32 %50
Broken module found, compilation aborted!
Stack dump:
0.      Running pass 'Function Pass Manager' on module 'main'.
1.      Running pass 'Module Verifier' on function '@layerpot'
[1]    25966 abort      python -c

Here's a quick one-liner to reproduce the crash.

python -c 'import pyopencl as cl ; ctx = cl._csc(); cl.Program(ctx, open("qbx.cl.txt").read()).build()'