As described in issue llvm/llvm-project#91518, a previous PR
llvm/llvm-project#78484 introduced the `defaultMemorySpaceFn` into
bufferization options, allowing one to inform OneShotBufferize that it
should use a specified function to derive the memory space attribute
from the encoding attribute attached to tensor types.
However, introducing this feature exposed unhandled edge cases,
examples of which are introduced by this change in the new test under
`test/Dialect/Bufferization/Transforms/one-shot-bufferize-encodings.mlir`.
Fixing the inconsistencies introduced by `defaultMemorySpaceFn` is
pretty simple. This change:
- Updates the `bufferization.to_memref` and `bufferization.to_tensor`
operations to explicitly include operand and destination types,
whereas previously they relied on type inference to deduce the
tensor types. Since the type inference cannot recover the correct
tensor encoding/memory space, the operand and result types must be
explicitly included. This is a small assembly format change, but it
touches a large number of test files.
- Makes minor updates to other bufferization functions to handle the
changes in building the above ops.
- Updates bufferization of `tensor.from_elements` to handle memory
space.
Integration/upgrade guide:
In downstream projects, if you have tests or MLIR files that explicitly
use
`bufferization.to_tensor` or `bufferization.to_memref`, then update
them to the new assembly format as follows:
```
%1 = bufferization.to_memref %0 : memref<10xf32>
%2 = bufferization.to_tensor %1 : memref<10xf32>
```
becomes
```
%1 = bufferization.to_memref %0 : tensor<10xf32> to memref<10xf32>
%2 = bufferization.to_tensor %0 : memref<10xf32> to tensor<10xf32>
```
Add write memory effect for the print operation. The exact memory
behavior is implemented in other print-like operations such as
`transform::PrintOp` or `gpu::printf`.
Providing memory behavior allows using the operation in passes like
buffer deallocation instead of emitting an error.
The buffer deallocation pass checks the IR ("operation preconditions")
to make sure that there is no IR that is unsupported. In such a case,
the pass signals a failure.
The pass now rejects all ops with unknown memory effects. We do not know
whether such an op allocates memory or not. Therefore, the buffer
deallocation pass does not know whether a deallocation op should be
inserted or not.
Memory effects are queried from the `MemoryEffectOpInterface` interface.
Ops that do not implement this interface but have the
`RecursiveMemoryEffects` trait do not have any side effects (apart from
the ones that their nested ops may have).
Unregistered ops are now rejected by the pass because they do not
implement the `MemoryEffectOpInterface` and neither do we know if they
have `RecursiveMemoryEffects` or not. All test cases that currently have
unregistered ops are updated to use registered ops.
