avoid overwriting skip_const_by_size via divide_to_multiply

[kentslaney]

No description provided.

[TobyRoseman]

Can you please include a unit test.

[kentslaney]

The following check currently fails on main:

coremltools/coremltools/converters/mil/mil/passes/tests/test_passes.py

Line 5499 in 9063b84

check_counts(divs=1, muls=1, const_skip=32)

common::const_elimination has skip_const_by_size set to 32, but the denominator is turned into a constant anyway

[TobyRoseman]

Thanks for adding a unit test. The code change looks good.

CI: https://gitlab.com/coremltools1/coremltools/-/pipelines/2218228187

[kentslaney]

Quick disclaimer: one trade-off I made unilaterally was not putting a separate option in divide_to_multiply akin to skip_const_by_size. I haven't looked into the performance factor for the graph pass, but the options are modular and I don't think it's worth the added complexity.

[TobyRoseman]

Thanks @kentslaney