[all-commits] [llvm/llvm-project] 00a93e: [mlir:python] Change PyOperation::create to actual...

[Peter Hawkins via All-commits]

  Branch: refs/heads/main
  Home:   https://github.com/llvm/llvm-project
  Commit: 00a93e6207ac053e7a42368a52cf51a744ecd139
      https://github.com/llvm/llvm-project/commit/00a93e6207ac053e7a42368a52cf51a744ecd139
  Author: Peter Hawkins <phawkins at google.com>
  Date:   2024-11-05 (Tue, 05 Nov 2024)

  Changed paths:
    M mlir/lib/Bindings/Python/IRCore.cpp

  Log Message:
  -----------
  [mlir:python] Change PyOperation::create to actually return a PyOperation. (#114542)

In the tablegen-generated Python bindings, we typically see a pattern
like:
```
class ConstantOp(_ods_ir.OpView):
  ...
  def __init__(self, value, *, loc=None, ip=None):
    ...
    super().__init__(self.build_generic(attributes=attributes, operands=operands, successors=_ods_successors, regions=regions, loc=loc, ip=ip))
```

i.e., the generated code calls `OpView.__init__()` with the output of
`build_generic`. The purpose of `OpView` is to wrap another operation
object, and `OpView.__init__` can accept any `PyOperationBase` subclass,
and presumably the intention is that `build_generic` returns a
`PyOperation`, so the user ends up with a `PyOpView` wrapping a
`PyOperation`.

However, `PyOpView::buildGeneric` calls `PyOperation::create`, which
does not just build a PyOperation, but it also calls `createOpView` to
wrap that operation in a subclass of `PyOpView` and returns that view.
But that's rather pointless: we called this code from the constructor of
an `OpView` subclass, so we already have a view object ready to go; we
don't need to build another one!

If we change `PyOperation::create` to return the underlying
`PyOperation`, rather than a view wrapper, we can save allocating a
useless `PyOpView` object for each ODS-generated Python object.

This saves approximately 1.5s of Python time in a JAX LLM benchmark that
generates a mixture of upstream dialects and StableHLO.



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