- Adding support for Mxnet flavored dequantization for both default and using MKLDNN. User can choose between the two at runtime. (#3945)

- Added tests for new methods added.

* move the number of nodes constraint in op fusion up to the dom tree level

* add test case of limiting the max number of ops to be fused

* uncomment other test cases

The torch package depends on the future package but the torch wheel
does not expose that dependency resulting in an inconsitent install.

Ideally the wheel should declare all of its dependencies, I'm not sure
why the packagers have choosen not to do this, for now the simple work
around is to explicitly install the future package.

Change-Id: Ic9f0f4bb4c78ab65706fc1b20c1b4fd287856a9e

* [Relay][VM] Fix constant folding issue in VM compiler

1. allow pass params when compile a module
2. enhance profiler robustness

* remove dead code

* fix lint

* add get_params

* fix test

* don't pass params back

* remove get_params

* docs

* move compile function to api

* compile clashes with builtin name

* fix compilation error

* remove dead code

* add valid autotune

* fix pylint

The current bounds checking infrastructure inserts checks like:

```
for (i, 0, bounds[n]) {
  if (likely(i < bounds[n]) {
     ...
  }
}
```

into the TVM IR which is currently not removed by simplification infrastructure.
This is a little unclean, as these are trivially true since for a loop var `i`
with a given min and extent, we are guaranteed that `i >= min` and `i < min +
extent`. Thus, we can insert these checks into the IR and use them to eliminate
trivial bounds checks early on.

Use fdiv in the tests for the deduce_bound

if n_trial is larger then config space.

Issue:
git clone latest TVM/VTA and run VTA on xilinx FPGA board, application
crashed due to the "call stack overflow" which caused by a infinite recursive
function call. this issue ever happen before and get addressed by PR 3843.

Analysis:
seems like de10-nano driver PR  used old code base then the  logic change
of 3843 get eliminated.

Solution:
add the logic back.

The -mfloat-abi hard option does not work for LLVM < 6.0 as it is ignored.
This adds a fatal error when using unsupported LLVM versions so that the failure
is not silent.

* Fix VM invoke with set_params

* add test

* tweak

In current implementation HIDE_PRIVATE_SYMBOLS hides symbols from TVM
itself but not from its dependent libraries. This is problematic when
other third-party libraries with the same symbols are linked to the
same executable.

One example is using TVM with Mesa OpenCL drivers: they depend on LLVM
and load its shared libraries with RTLD_GLOBAL flag, which results in
conflicts with LLVM symbols that TVM uses. Arguably this particular
issue belongs to Mesa (here's their tracking bug:
https://gitlab.freedesktop.org/mesa/mesa/issues/236) but in general
that's the right thing to do regardless of this particular bug.

Note that I'm not enabling this functionality for Darwin as in my
earlier tests their linker didn't seem to understand "--exclude-libs"
(but I don't have test platform ATM to double-check).

fix some typos

The tensorflow zeros_like operation provided in array_ops.py produces directly a tensor with zeros
without a graph, using only the shape and type of the input. This imposes the use of gen_array_ops.py
that produces both a tensor and a graph so a comparison between tflite and tvm can be done.

@zhiics @icemelon9

* [Relay][VM] Add more passes to VMCompiler

* Check build config

* Add todo

* fix

* tweak

* save

save

redo max test

save

address comment

fix

* address comment

* increase rtol

* address review comment

* [Relay][Op] Add instance norm op

* mend

[Relay][Op] Add instance norm op

* [TF][Op] Add TF op Where

* improve tests

* add tests for vm

* Add op argwhere

* Move shape func to _algorithm.py

* Add lint rule

* Raise exception if rank is not supportted

* move argwhere to transform

* Add argwhere example

* Fix lint

* Add 1-d support

* cleanup

* Add more dtype support

* CR comment

* Improve error message

* Docs

* raise exception