The SCF helper for tiling an operation implementing the TilingInterface
and greedily fusing consumers requires an uninterrupted chain of
operations implementing the tiling interface to succeed. There can be
cases with intermediate ops that don't implement the interface but have
producers that could be fused if various canonicalization/simplification
patterns could run in between fusion steps.
This adds an option to SCFTileAndFuseOptions for a pattern set to run
between fusion steps to the ops that result from fusion/tiling. Removed
and newly inserted slices are tracked for continued fusion applications.
See this RFC for more discussion:
https://discourse.llvm.org/t/rfc-split-fusion-portions-of-the-tilinginterface-into-a-new-interface/81155
-- This commit extends consumer fusion to take place even if the
producer has multiple uses.
-- The multiple uses of the producer essentially means that besides the
consumer op in concern, the only other uses of the producer are
allowed in :-
1. scf.yield
2. tensor.parallel_insert_slice
Signed-off-by: Abhishek Varma <abhvarma@amd.com>
Current implementation of `scf::tileConsumerAndFuseProducerUsingSCF`
looks at operands of tiled/tiled+fused operations to see if they are
produced by `extract_slice` operations to populate the worklist used to
continue fusion. This implicit assumption does not always work. Instead
make the implementations of `getTiledImplementation` return the slices
to use to continue fusion.
This is a breaking change
- To continue to get the same behavior of
`scf::tileConsumerAndFuseProducerUsingSCF`, change all out-of-tree
implementation of `TilingInterface::getTiledImplementation` to return
the slices to continue fusion on. All in-tree implementations have been
adapted to this.
- This change touches parts that required a simplification to the
`ControlFn` in `scf::SCFTileAndFuseOptions`. It now returns a
`std::optional<scf::SCFTileAndFuseOptions::ControlFnResult>` object that
should be `std::nullopt` if fusion is not to be performed.
Signed-off-by: MaheshRavishankar <mahesh.revishankar@gmail.com>
Refactor current consumer fusion based on `addInitOperandsToLoopNest` to support single nested `scf.for`, E.g.
```
%0 = scf.for() {
%1 = scf.for() {
tiledProducer
}
yield %1
}
%2 = consumer ins(%0)
```
Compared with #94190, this PR fix build failure by making C++17 happy.
Refactor current consumer fusion based on `addInitOperandsToLoopNest` to support single nested `scf.for`, E.g.
```
%0 = scf.for() {
%1 = scf.for() {
tiledProducer
}
yield %1
}
%2 = consumer ins(%0)
```
The implementation of these methods are legacy and they are removed in
favor of using the `scf::tileUsingSCF` methods as replacements. To get
the latter on par with requirements of the deprecated methods, the
tiling allows one to specify the maximum number of tiles to use instead
of specifying the tile sizes. When tiling to `scf.forall` this
specification is used to generate the `num_threads` version of the
operation.
A slight deviation from previous implementation is that the deprecated
method always generated the `num_threads` variant of the `scf.forall`
operation. Instead now this is driven by the tiling options specified.
This reduces the indexing math generated when the tile sizes are
specified.
**Moving from `linalg::tileToForallOp` to `scf::tileUsingSCF`**
```
OpBuilder b;
TilingInterface op;
ArrayRef<OpFoldResult> numThreads;
ArrayAttr mapping;
FailureOr<ForallTilingResult> result =linalg::tileToForallOp(b, op, numThreads, mapping);
```
can be replaced by
```
scf::SCFTilingOptions options;
options.setNumThreads(numThreads);
options.setLoopType(scf::SCFTilingOptions::LoopType::ForallOp);
options.setMapping(mapping.getValue()); /*note the difference that setMapping takes an ArrayRef<Attribute> */
FailureOr<scf::SCFTilingResult> result = scf::tileUsingSCF(b, op, options);
```
This generates the `numThreads` version of the `scf.forall` for the
inter-tile loops, i.e.
```
... = scf.forall (%arg0, %arg1) in (%nt0, %nt1) shared_outs(...)
```
**Moving from `linalg::tileToForallOpUsingTileSizes` to
`scf::tileUsingSCF`**
```
OpBuilder b;
TilingInterface op;
ArrayRef<OpFoldResult> tileSizes;
ArrayAttr mapping;
FailureOr<ForallTilingResult> result =linalg::tileToForallOpUsingTileSizes(b, op, tileSizes, mapping);
```
can be replaced by
```
scf::SCFTilingOptions options;
options.setTileSizes(tileSizes);
options.setLoopType(scf::SCFTilingOptions::LoopType::ForallOp);
options.setMapping(mapping.getValue()); /*note the difference that setMapping takes an ArrayRef<Attribute> */
FailureOr<scf::SCFTilingResult> result = scf::tileUsingSCF(b, op, options);
```
Also note that `linalg::tileToForallOpUsingTileSizes` would effectively
call the `linalg::tileToForallOp` by computing the `numThreads` from the
`op` and `tileSizes` and generate the `numThreads` version of the
`scf.forall`. That is not the case anymore. Instead this will directly
generate the `tileSizes` version of the `scf.forall` op
```
... = scf.forall(%arg0, %arg1) = (%lb0, %lb1) to (%ub0, %ub1) step(%step0, %step1) shared_outs(...)
```
If you actually want to use the `numThreads` version, it is upto the
caller to compute the `numThreads` and set `options.setNumThreads`
instead of `options.setTileSizes`. Note that there is a slight
difference in the num threads version and tile size version. The former
requires an additional `affine.max` on the tile size to ensure
non-negative tile sizes. When lowering to `numThreads` version this
`affine.max` is not needed since by construction the tile sizes are
non-negative. In previous implementations, the `numThreads` version
generated when using the `linalg::tileToForallOpUsingTileSizes` method
would avoid generating the `affine.max` operation. To get the same
state, downstream users will have to additionally normalize the
`scf.forall` operation.
**Changes to `transform.structured.tile_using_forall`**
The transform dialect op that called into `linalg::tileToForallOp` and
`linalg::tileToForallOpUsingTileSizes` have been modified to call
`scf::tileUsingSCF`. The transform dialect op always generates the
`numThreads` version of the `scf.forall` op. So when `tile_sizes` are
specified for the transform dialect op, first the `tile_sizes` version
of the `scf.forall` is generated by the `scf::tileUsingSCF` method which
is then further normalized to get back to the same state. So there is no
functional change to `transform.structured.tile_using_forall`. It always
generates the `numThreads` version of the `scf.forall` op (as it did
before this change).
---------
Signed-off-by: MaheshRavishankar <mahesh.ravishankar@gmail.com>
This patch extends the functionality of yielding replacement for multiple
results case and adds another optional argument called `yieldResultNumber`
indicating which result(s) need yield. If not given, all of results will be yield
by default.
The `TilingInterface` methods have return values that allow the
interface implementation to return multiple operations, and also return
tiled values explicitly. This is to avoid the assumption that the
interface needs to return a single operation and this operations result
are the expected tiled values. Make the
`PartialReductionOpInterface::tileToPartialReduction` return
`TilingResult` as well for the same reason.
Similarly make the `PartialReductionOpInterface::mergeReductions` also
return a list of generated operations and values to use as replacements.
This is just a refactoring to allow for deprecation of
`linalg::tileReductionUsingForall` with `scf::tileReductionUsingSCF`
method.
This commit adds an API (`tileAndFuseConsumerOfSlice`) to fuse consumer to a producer within
scf.for/scf.forall loop.
To support this two new methods are added to the `TilingInterface`
- `getIterationDomainTileFromOperandTile`
- `getTiledImplementationFromOperandTile`.
Consumer operations that implement this method can be used to be fused with tiled producer operands in a manner similar to (but essentially the inverse of) the fusion of an untiled producer with a tiled consumer.
Note that this only does one `tiled producer` -> `consumer` fusion. This could be called repeatedly for fusing multiple consumers. The current implementation also is conservative in when this kicks in (like single use of the value returned by the inter-tile loops that surround the tiled producer, etc.) These can be relaxed over time.
Signed-off-by: Abhishek Varma <abhvarma@amd.com>
---------
Signed-off-by: Abhishek Varma <abhvarma@amd.com>
Signed-off-by: Abhishek Varma <avarma094@gmail.com>
Co-authored-by: cxy <chenxunyu1993@gmail.com>
This patch adds support for reducing operations with multiple results
using PartialReductionOpInterface. Also adds an implementation of
PartialReductionOpInterface for multiple results for linalg.generic.
Using `LoopLikeOpInterface` as the basis for the implementation unifies
all the tiling logic for both `scf.for` and `scf.forall`. The only
difference is the actual loop generation. This is a follow up to
https://github.com/llvm/llvm-project/pull/72178
Instead of many entry points for each loop type, the loop type is now
passed as part of the options passed to the tiling method.
This is a breaking change with the following changes
1) The `scf::tileUsingSCFForOp` is renamed to `scf::tileUsingSCF`
2) The `scf::tileUsingSCFForallOp` is deprecated. The same
functionality is obtained by using `scf::tileUsingSCF` and setting
the loop type in `scf::SCFTilingOptions` passed into this method to
`scf::SCFTilingOptions::LoopType::ForallOp` (using the
`setLoopType` method).
3) The `scf::tileConsumerAndFusedProducerGreedilyUsingSCFForOp` is
renamed to `scf::tileConsumerAndFuseProducerUsingSCF`. The use of
the `controlFn` in `scf::SCFTileAndFuseOptions` allows implementing
any strategy with the default callback implemeting the greedy fusion.
4) The `scf::SCFTilingResult` and `scf::SCFTileAndFuseResult` now use
`SmallVector<LoopLikeOpInterface>`.
5) To make `scf::ForallOp` implement the parts of
`LoopLikeOpInterface` needed, the `getOutputBlockArguments()`
method is replaced with `getRegionIterArgs()`
These changes now bring the tiling and fusion capabilities using
`scf.forall` on par with what was already supported by `scf.for`
This commit renames 4 pattern rewriter API functions:
* `updateRootInPlace` -> `modifyOpInPlace`
* `startRootUpdate` -> `startOpModification`
* `finalizeRootUpdate` -> `finalizeOpModification`
* `cancelRootUpdate` -> `cancelOpModification`
The term "root" is a misnomer. The root is the op that a rewrite pattern
matches against
(https://mlir.llvm.org/docs/PatternRewriter/#root-operation-name-optional).
A rewriter must be notified of all in-place op modifications, not just
in-place modifications of the root
(https://mlir.llvm.org/docs/PatternRewriter/#pattern-rewriter). The old
function names were confusing and have contributed to various broken
rewrite patterns.
Note: The new function names use the term "modify" instead of "update"
for consistency with the `RewriterBase::Listener` terminology
(`notifyOperationModified`).
In the process a couple of test transform dialect ops are added just
for testing. These operations are not intended to use as full flushed
out of transformation ops, but are rather operations added for testing.
A separate operation is added to `LinalgTransformOps.td` to convert a
`TilingInterface` operation to loops using the
`generateScalarImplementation` method implemented by the
operation. Eventually this and other operations related to tiling
using the `TilingInterface` need to move to a better place (i.e. out
of `Linalg` dialect)
Currently the `tileConsumerAndFuseProducerGreedilyUsingSCFFor` method
greedily fuses through all slices that are generated during the tile and
fuse flow. That is not the normal use case. Ideally the caller would
like to control which slices get fused and which dont. This patch
introduces a new field to the `SCFTileAndFuseOptions` to specify this
control.
The contol function also allows the caller to specify if the replacement
for the fused producer needs to be yielded from within the tiled
computation. This allows replacing the fused producers in case they have
other uses. Without this the original producers still survive negating
the utility of the fusion.
The change here also means that the name of the function
`tileConsumerAndFuseProducerGreedily...` can be updated. Defering that
to a later stage to reduce the churn of API changes.
/llvm-project/mlir/lib/Dialect/SCF/Transforms/TileUsingInterface.cpp:703:5: error: non-void lambda does not return a value in all
control paths [-Werror,-Wreturn-type]
};
^
1 error generated.
The current implementation of tiling using `scf.for` is convoluted to
make sure that the destination passing style of the untiled program is
preserved. The addition of support to tile using `scf.forall` (adapted
from the transform operation in Linalg) in
https://github.com/llvm/llvm-project/pull/67083 used cloning of the
tiled operations to better streamline the implementation. This PR adapts
the other tiling methods to use a similar approach, making the
transformations (and handling destination passing style semantics) more
systematic.
---------
Co-authored-by: Abhishek-Varma <avarma094@gmail.com>
Expose loop results, which correspond to the region iter_arg values that
are returned from the loop when there are no more iterations. Exposing
loop results is optional because some loops (e.g., `scf.while`) do not
have a 1-to-1 mapping between region iter_args and op results.
Also add additional helper functions to query tied
results/iter_args/inits.
The `LoopLikeOpInterface` already has interface methods to query inits
and iter_args. This commit adds helper functions to query tied
init/iter_arg pairs and removes the corresponding functions for
`scf::ForOp`.
A recent change modified the parameter tileSize from Value to
OpFoldResult. Therefore we should call getAsOpFoldResult before passing
on the tileSize.
Adjust a test regarding this new behavior.
Similar to `scf::tileUsingSCFForOp` that is a method that tiles
operations that implement the `TilingInterface`, using `scf.for`
operations, this method introduces tiling of operations using
`scf.forall`. Most of this implementation is derived from
`linalg::tileToForallOp` method. Eventually that method will either be
deprecated or moved to use the method introduced here.
The TableGen code generator now generates C++ code that returns a single
`OpOperand &` for `get...Mutable` of operands that are not variadic and
not optional. `OpOperand::set`/`assign` can be used to set a value (same
as `MutableOperandRange::assign`). This is safer than
`MutableOperandRange` because only single values (and no longer
`ValueRange`) can be assigned.
E.g.:
```
// Assignment of multiple values to non-variadic operand.
// Before: Compiles, but produces invalid op.
// After: Compilation error.
extractSliceOp.getSourceMutable().assign({v1, v2});
```
`affine::replaceForOpWithNewYields` and `replaceLoopWithNewYields` (for
"scf.for") are now interface methods and additional loop-carried
variables can now be added to "scf.for"/"affine.for" uniformly. (No more
`TypeSwitch` needed.)
Note: `scf.while` and other loops with loop-carried variables can
implement `replaceWithAdditionalYields`, but to keep this commit small,
that is not done in this commit.
* "init" operands are specified with `MutableOperandRange` (which gives
access to the underlying `OpOperand *`). No more magic numbers.
* Remove most interface methods and make them helper functions. Only
`getInitsMutable` should be implemented.
* Provide separate helper functions for accessing mutable/immutable
operands (`OpOperand`/`Value`, in line with #66515): `getInitsMutable`
and `getInits` (same naming convention as auto-generated op accessors).
`getInputOperands` was not renamed because this function cannot return a
`MutableOperandRange` (because the operands are not necessarily
consecutive). `OpOperandVector` is no longer needed.
* The new `getDpsInits`/`getDpsInitsMutable` is more efficient than the
old `getDpsInitOperands` because no `SmallVector` is created. The new
functions return a range of operands.
* Fix a bug in `getDpsInputOperands`: out-of-bounds operands were
potentially returned.
This function was inconsistent with the remaining API because it
accepted `OpOperand &` that do not belong to the op. All the other
functions assert. This helper function is also not really necessary, as
the iter_arg number is identical to the result number.
In line with #66515, change `MutableArrayRange::begin`/`end` to
enumerate `OpOperand &` instead of `Value`. Also remove
`ForOp::getIterOpOperands`/`setIterArg`, which are now redundant.
Note: `MutableOperandRange` cannot be made a derived class of
`indexed_accessor_range_base` (like `OperandRange`), because
`MutableOperandRange::assign` can change the number of operands in the
range.
`operator[]` returns `OpOperand &` instead of `Value`.
* This allows users to get OpOperands by name instead of "magic" number.
E.g., `extractSliceOp->getOpOperand(0)` can be written as
`extractSliceOp.getSourceMutable()[0]`.
* `OperandRange` provides a read-only API to operands: `operator[]`
returns `Value`. `MutableOperandRange` now provides a mutable API:
`operator[]` returns `OpOperand &`, which can be used to set operands.
Note: The TableGen code generator could be changed to return `OpOperand
&` (instead of `MutableOperandRange`) for non-variadic and non-optional
arguments in a subsequent change. Then the `[0]` part in the above
example would no longer be necessary.
This patch improves the reduction tiling for linalg to support multiple
reduction dimensions.
Reviewed By: mravishankar
Differential Revision: https://reviews.llvm.org/D158005
* Remove duplicate functions. `tensor::getMixedSize` and `tensor::getMixedSizes` should be used.
* Use `tensor::getMixedSize` instead of `createOrFold<tensor::DimOp>`. This is more efficient. `createOrFold` will create an op an immediately try to fold it. In case of a static dimension size, an attribute can be used directly.
Differential Revision: https://reviews.llvm.org/D153332
The MLIR classes Type/Attribute/Operation/Op/Value support
cast/dyn_cast/isa/dyn_cast_or_null functionality through llvm's doCast
functionality in addition to defining methods with the same name.
This change begins the migration of uses of the method to the
corresponding function call as has been decided as more consistent.
Note that there still exist classes that only define methods directly,
such as AffineExpr, and this does not include work currently to support
a functional cast/isa call.
Caveats include:
- This clang-tidy script probably has more problems.
- This only touches C++ code, so nothing that is being generated.
Context:
- https://mlir.llvm.org/deprecation/ at "Use the free function variants
for dyn_cast/cast/isa/…"
- Original discussion at https://discourse.llvm.org/t/preferred-casting-style-going-forward/68443
Implementation:
This first patch was created with the following steps. The intention is
to only do automated changes at first, so I waste less time if it's
reverted, and so the first mass change is more clear as an example to
other teams that will need to follow similar steps.
Steps are described per line, as comments are removed by git:
0. Retrieve the change from the following to build clang-tidy with an
additional check:
https://github.com/llvm/llvm-project/compare/main...tpopp:llvm-project:tidy-cast-check
1. Build clang-tidy
2. Run clang-tidy over your entire codebase while disabling all checks
and enabling the one relevant one. Run on all header files also.
3. Delete .inc files that were also modified, so the next build rebuilds
them to a pure state.
4. Some changes have been deleted for the following reasons:
- Some files had a variable also named cast
- Some files had not included a header file that defines the cast
functions
- Some files are definitions of the classes that have the casting
methods, so the code still refers to the method instead of the
function without adding a prefix or removing the method declaration
at the same time.
```
ninja -C $BUILD_DIR clang-tidy
run-clang-tidy -clang-tidy-binary=$BUILD_DIR/bin/clang-tidy -checks='-*,misc-cast-functions'\
-header-filter=mlir/ mlir/* -fix
rm -rf $BUILD_DIR/tools/mlir/**/*.inc
git restore mlir/lib/IR mlir/lib/Dialect/DLTI/DLTI.cpp\
mlir/lib/Dialect/Complex/IR/ComplexDialect.cpp\
mlir/lib/**/IR/\
mlir/lib/Dialect/SparseTensor/Transforms/SparseVectorization.cpp\
mlir/lib/Dialect/Vector/Transforms/LowerVectorMultiReduction.cpp\
mlir/test/lib/Dialect/Test/TestTypes.cpp\
mlir/test/lib/Dialect/Transform/TestTransformDialectExtension.cpp\
mlir/test/lib/Dialect/Test/TestAttributes.cpp\
mlir/unittests/TableGen/EnumsGenTest.cpp\
mlir/test/python/lib/PythonTestCAPI.cpp\
mlir/include/mlir/IR/
```
Differential Revision: https://reviews.llvm.org/D150123
FuncOp is IsolatedFromAbove, so this change doesn't alter current behaviour, but the current code fails if the tile op is in an op with IsolatedFromAbove trait.
An alternative would be to create constant in the same region where they're used a rely on CSE to figure out where to move them.
Differential Revision: https://reviews.llvm.org/D147273
Currently the `getTiledImplementation` and `generateResultTileValue`
return just `SmallVector<Operation *>` and `FailureOr<Value>`.
- For `getTiledImplementation` returning empty implies tiling wasnt
done. There is also an implicit assumption that the tiled operation
results correspond to the tiled values of the result of the original
operation. This cannot handle cases where the tiled implementation
might use multiple operations to compute the tiled value for the
results of the untiled operation. Sometimes, the tiled operation
might not directly give the tiled values, and might require casts,
etc to get a replacement.
- For `generateResultTileValue`, it is assumed that the op defining
the returned `Value` is the operation that represents the tiled
computation. Again presence of casts, etc violate this.
Instead make these methods return
```
struct TilingResult {
SmallVector<Operation *> tiledOps;
SmallVector<Value> tiledValues;
};
```
The `tiledOps` represent the operations generated that are relevant
for subsequent transformations. The `tiledValues` represent the tiled
values for the results of the original operation. This better
transmits the state of the transformed IR.
As a consequence the following methods also return `FailureOr<TilingResult>`
- `tensor::replaceExtractSliceWithTiledProducer`
- `tensor::bubbleUpPadSlice`
Differential Revision: https://reviews.llvm.org/D145133
This does not work by a mere composition of `enumerate` and `zip_equal`,
because C++17 does not allow for recursive expansion of structured
bindings.
This implementation uses `zippy` to manage the iteratees and adds the
stream of indices as the first zipped range. Because we have an upfront
assertion that all input ranges are of the same length, we only need to
check if the second range has ended during iteration.
As a consequence of using `zippy`, `enumerate` will now follow the
reference and lifetime semantics of the `zip*` family of functions. The
main difference is that `enumerate` exposes each tuple of references
through a new tuple-like type `enumerate_result`, with the familiar
`.index()` and `.value()` member functions.
Because the `enumerate_result` returned on dereference is a
temporary, enumeration result can no longer be used through an
lvalue ref.
Reviewed By: dblaikie, zero9178
Differential Revision: https://reviews.llvm.org/D144503
The `candidateSliceOp` was replaces and used in a subsequent
call. Instead just replace its uses. The op is dead and will be
removed with CSE.
Differential Revision: https://reviews.llvm.org/D141869
This patch adds an option to the method that fuses a producer with a
tiled consumer, to also yield from the tiled loops a value that can be
used to replace the original producer. This is only valid if it can be
assertained that the slice of the producer computed within each
iteration of the tiled loop nest does not compute slices of the
producer redundantly. The analysis to derive this is very involved. So
this is left to the caller to assertain. A test is added that mimics
the `scf::tileConsumerAndFuseProducersGreedilyUsingSCFForOp`, but also
yields the values of all fused producers. This can be used as a
reference for how a caller could use this functionality.
Differential Revision: https://reviews.llvm.org/D141028
Add a new utility method to yield the tiled value as well as
preserving destination passing style.
Differential Revision: https://reviews.llvm.org/D139392
A transformation tiling a reduction dimension of a Linalg op needs a
tile size for said dimension. When an insufficient number of dimensions
was provided, it would segfault due to out-of-bounds access to a vector.
Also fix incorrect error reporting in the structured transform op
exercising this functionality.
Reviewed By: springerm, ThomasRaoux
Differential Revision: https://reviews.llvm.org/D141046
std::optional::value() has undesired exception checking semantics and is
unavailable in older Xcode (see _LIBCPP_AVAILABILITY_BAD_OPTIONAL_ACCESS). The
call sites block std::optional migration.
This is part of an effort to migrate from llvm::Optional to
std::optional. This patch changes the way mlir-tblgen generates .inc
files, and modifies tests and documentation appropriately. It is a "no
compromises" patch, and doesn't leave the user with an unpleasant mix of
llvm::Optional and std::optional.
A non-trivial change has been made to ControlFlowInterfaces to split one
constructor into two, relating to a build failure on Windows.
See also: https://discourse.llvm.org/t/deprecating-llvm-optional-x-hasvalue-getvalue-getvalueor/63716
Signed-off-by: Ramkumar Ramachandra <r@artagnon.com>
Differential Revision: https://reviews.llvm.org/D138934
