Such IR is rejected by default, but can be allowed with `allow-return-memref`. In preparation of future refactorings, do not deallocate such buffers.
One-Shot Analysis now gathers information about yielded tensors, so that we know during the actual bufferization whether a newly allocated buffer should be deallocated again. (Otherwise, it will leak. This will be addressed in a subsequent commit that also makes `allow-return-memref` a non-experimental flag.)
As a cleanup, `allow-return-memref` is now part of OneShotBufferizationOptions. (It was previously ignored by AlwaysCopyBufferizationState.) Moreover, AlwaysCopyBufferizationState now asserts that `create-deallocs` is deactivated to prevent surprising behavior.
Differential Revision: https://reviews.llvm.org/D121521
The related functionality is moved over to the bufferization dialect. Test cases are cleaned up a bit.
Differential Revision: https://reviews.llvm.org/D120191
