How to disable folding for particular ops in applyPatternsAndFoldGreedily?

[Alexander Pivovarov]

Hello Everyone

LowerComplex mhlo pass uses applyPatternsAndFoldGreedily.

The doc says

/// Also performs folding and simple dead-code elimination before attempting to

/// match any of the provided patterns.

How to disable folding for particular ops?

In particular I need to preserve mhlo.copy op

The only workaround I found so far is to patch hlo_ops.cc and return {} in CopyOp::fold() instead of getOperand().

I would appreciate any help and ideas

Thank you

Alex