Previously, linalg-bufferize was a "finalizing" bufferization pass (it
did a "full" conversion). This wasn't great because it couldn't be used
composably with other bufferization passes like std-bufferize and
scf-bufferize.
This patch makes linalg-bufferize a composable bufferization pass.
Notice that the integration tests are switched over to using a pipeline
of std-bufferize, linalg-bufferize, and (to finalize the conversion)
func-bufferize. It all "just works" together.
While doing this transition, I ran into a nasty bug in the 1-use special
case logic for forwarding init tensors. That logic, while
well-intentioned, was fundamentally flawed, because it assumed that if
the original tensor value had one use, then the converted memref could
be mutated in place. That assumption is wrong in many cases. For
example:
```
%0 = some_tensor : tensor<4xf32>
br ^bb0(%0, %0: tensor<4xf32>, tensor<4xf32>)
^bb0(%bbarg0: tensor<4xf32>, %bbarg1: tensor<4xf32>)
// %bbarg0 is an alias of %bbarg1. We cannot safely write
// to it without analyzing uses of %bbarg1.
linalg.generic ... init(%bbarg0) {...}
```
A similar example can happen in many scenarios with function arguments.
Even more sinister, if the converted memref is produced by a
`std.get_global_memref` of a constant global memref, then we might
attempt to write into read-only statically allocated storage! Not all
memrefs are writable!
Clearly, this 1-use check is not a local transformation that we can do
on the fly in this pattern, so I removed it.
The test is now drastically shorter and I basically rewrote the CHECK
lines from scratch because:
- the new composable linalg-bufferize just doesn't do as much, so there
is less to test
- a lot of the tests were related to the 1-use check, which is now gone,
so there is less to test
- the `-buffer-hoisting -buffer-deallocation` is no longer mixed in, so
the checks related to that had to be rewritten
Differential Revision: https://reviews.llvm.org/D90657
The bufferization patterns are moved to the .cpp file, which is
preferred in the codebase when it makes sense.
The LinalgToStandard patterns are kept a header because they are
expected to be used individually. However, they are moved to
LinalgToStandard.h which is the file corresponding to where they are
defined.
This also removes TensorCastOpConverter, which is handled by
populateStdBufferizePatterns now. Eventually, the constant op lowering
will be handled as well, but it there are currently holdups on moving
it (see https://reviews.llvm.org/D89916).
Differential Revision: https://reviews.llvm.org/D90254
This class represents a rewrite pattern list that has been frozen, and thus immutable. This replaces the uses of OwningRewritePatternList in pattern driver related API, such as dialect conversion. When PDL becomes more prevalent, this API will allow for optimizing a set of patterns once without the need to do this per run of a pass.
Differential Revision: https://reviews.llvm.org/D89104
