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Problem with equality operator of `expr.Mod`?

See original GitHub issue

I’m looking at unit test of ir builder, looks like the == operator does not work for Mod as expected:

    ib = tvm.ir_builder.create()
    n = tvm.var("n")
    A = ib.pointer("float32", name="A")
    with ib.for_range(0, n, name="i") as i:
        with ib.if_scope((i % 2) == 0):
            A[i] = A[i] + 1
        with ib.else_scope():
            A[0] = A[i] + 2

The generated IR is:

➜  ~ ipython
Python 2.7.10 (default, Jul 14 2015, 19:46:27)
Type "copyright", "credits" or "license" for more information.

IPython 5.1.0 -- An enhanced Interactive Python.
?         -> Introduction and overview of IPython's features.
%quickref -> Quick reference.
help      -> Python's own help system.
object?   -> Details about 'object', use 'object??' for extra details.

In [1]: import tvm
   ...:

In [2]:     ib = tvm.ir_builder.create()
   ...:     n = tvm.var("n")
   ...:     A = ib.pointer("float32", name="A")
   ...:     with ib.for_range(0, n, name="i") as i:
   ...:         with ib.if_scope((i % 2) == 0):
   ...:             A[i] = A[i] + 1
   ...:         with ib.else_scope():
   ...:             A[0] = A[i] + 2
   ...:
   ...:     body = ib.get()
   ...:

In [3]: body
Out[3]:
for (i, 0, n) {
  if (0) {
    A[i] = (A[i] + 1.000000f)
  } else {
    A[0] = (A[i] + 2.000000f)
  }
}

Note that the condition expression is constant 0 instead of an equality check expression. The __eq__ operator for Mod comes from tvm/_ffi/node.py

In [4]: i = ib.for_range(0, n, name="i")

In [5]: a = i._enter_value % 1

In [6]: a.__eq__.im_func
Out[6]: <function tvm._ffi.node.__eq__>

Which I assume what we want is tvm/expr.py?

I modify the unit test to use self.equal directly, and the code now makes sense to me:

In [7]: %paste
    ib = tvm.ir_builder.create()
    n = tvm.var("n")
    A = ib.pointer("float32", name="A")
    with ib.for_range(0, n, name="i") as i:
        with ib.if_scope((i % 2).equal(0)):
            A[i] = A[i] + 1
        with ib.else_scope():
            A[0] = A[i] + 2

    body = ib.get()
## -- End pasted text --

In [8]: body
Out[8]:
for (i, 0, n) {
  if (((i % 2) == 0)) {
    A[i] = (A[i] + 1.000000f)
  } else {
    A[0] = (A[i] + 2.000000f)
  }
}

Let me know if you think this is a problem. I’d be interested to help figure out why.