The hoistRedundantVectorTransfers function does not verification of loop
bounds when hoisting vector transfers. This is not safe in general,
since it is possible that the loop will have zero trip count. This PR
uses ValueBounds to verify that the lower bound is less than the upper
bound of the loop before hoisting. Trip count verification is currently
behind an option `verifyNonZeroTrip`, which is false by default.
Zero trip count loops can arise in GPU code generation, where a loop
bound can be dependent on a thread id. If not all threads execute the
loop body, then hoisting out of the loop can cause these threads to
execute the transfers when they are not supposed to.
---------
Signed-off-by: Max Dawkins <max.dawkins@gmail.com>
Recent changes (https://github.com/llvm/llvm-project/pull/66930)
disabled vector transfer ops hoisting with view-like intermediate ops.
The recommended way is to fold subview ops into transfer op indices
before invoking hoisting. That would mean now we see transfer op indices
involving dynamic values, instead of static constant values before with
subview ops. Therefore hoisting won't kick in anymore. This breaks
downstream users.
To fix it, this commit enables hoisting transfer ops with dynamic
indices by using `ValueBoundsConstraintSet` to prove ranges are disjoint
in `isDisjointTransferIndices`. Given that utility is used in many
places including op folders, right now we introduce a flag to it and
only set as true for "heavy" transforms in hoisting and load-store
forwarding.
`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.
This commit implements `LoopLikeOpInterface` on `scf.while`. This
enables LICM (and potentially other transforms) on `scf.while`.
`LoopLikeOpInterface::getLoopBody()` is renamed to `getLoopRegions` and
can now return multiple regions.
Also fix a bug in the default implementation of
`LoopLikeOpInterface::isDefinedOutsideOfLoop()`, which returned "false"
for some values that are defined outside of the loop (in a nested op, in
such a way that the value does not dominate the loop). This interface is
currently only used for LICM and there is no way to trigger this bug, so
no test is added.
Make sure that when analysing a `vector.transfer_read` that's a
candidate for either hoisting or store-to-load forwarding,
`memref.collapse_shape` Ops are correctly included in the alias
analysis. This is done by either
* making sure that relevant users are taken into account, or
* source Ops are correctly identified.
Do not hoist vector transfers that do not match exactly. In particular, do not hoist transfers with different vector types. This has lead to invalid IR (yielded vector type is different from iter_arg type) in downstream projects.
Differential Revision: https://reviews.llvm.org/D155052
Non-subview uses of an alloc outside the current loop
can be safely ignored when considering hoisting vector
transfer_reads. This patch adds a condition to check for that
case and updates the unit test accordingly.
Differential Revision: https://reviews.llvm.org/D150469
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
For singleton transfer reads, we allow hoisting them out
of the enclosing loop if its users are either transfer reads
or memory effect free.
Differential Revision: https://reviews.llvm.org/D146828
This revision significantly rewrites hoisting on tensors.
Previously, `vector.transfer_read/write` and `tensor.extract/insert_slice` would
be clumped together when looking for candidate pairs.
This would significantly increase the complexity of the logic and would not apply
independently to `tensor.extract/insert_slice`.
The new implementation decouples the cases and starts to cast the problem
as a generic matching subset extract/insert, which will be future proof when
other such operation pairs are introduced.
Lastly, the implementation makes the distinction clear between `vector.transfer_read/write` for
which we allow bypasses of the disjoint subsets from `tensor.extract/insert_slice` for which we
do not yet allow it.
This can be extended in the future and unified once we have subset disjunction implemented more generally.
The algorithm can be rewritten to be less of a fixed point with interspersed canonicalizations.
As a consequence, the test explicitly adds a canonicalization to clean up the IR and verify we end up in the same state.
That extra canonicalization exhibited that one of the uses in one of the tests was dead, so we fix the appropriate test.
Differential Revision: https://reviews.llvm.org/D144656
The only way to do this with the current hoisting strategy is by
lowering Affine to Scf first, but that prevents further passes on
Affine.
Differential Revision: https://reviews.llvm.org/D137600
The only way to do this with the current hoisting strategy is by
lowering Affine to Scf first, but that prevents further passes on
Affine.
Differential Revision: https://reviews.llvm.org/D137600
Improve hoisting logic to support cases where the read being hoisted
comes from a transfer_write with disjoint indices.
Differential Revision: https://reviews.llvm.org/D134624
This aligns the SCF dialect file layout with the majority of the dialects.
Reviewed By: jpienaar
Differential Revision: https://reviews.llvm.org/D128049
Now that dialect constructors are generated in the .cpp file, we can
drop all of the dependent dialect includes from the .h file.
Differential Revision: https://reviews.llvm.org/D124298
This has been on _Both for a couple of weeks. Flip usages in core with
intention to flip flag to _Prefixed in follow up. Needed to add a couple
of helper methods in AffineOps and Linalg to facilitate a pure flag flip
in follow up as some of these classes are used in templates and so
sensitive to Vector dialect changes.
Differential Revision: https://reviews.llvm.org/D122151
- Adds default implementations of `isDefinedOutsideOfLoop` and `moveOutOfLoop` since 99% of all implementations of these functions were identical
- `moveOutOfLoop` takes one operation and doesn't return anything anymore. 100% of all implementations of this function would always return `success` and uses would either respond with a pass failure or an `llvm_unreachable`.
This commit moves FuncOp out of the builtin dialect, and into the Func
dialect. This move has been planned in some capacity from the moment
we made FuncOp an operation (years ago). This commit handles the
functional aspects of the move, but various aspects are left untouched
to ease migration: func::FuncOp is re-exported into mlir to reduce
the actual API churn, the assembly format still accepts the unqualified
`func`. These temporary measures will remain for a little while to
simplify migration before being removed.
Differential Revision: https://reviews.llvm.org/D121266
The Func has a large number of legacy dependencies carried over from the old
Standard dialect, which was pervasive and contained a large number of varied
operations. With the split of the standard dialect and its demise, a lot of lingering
dead dependencies have survived to the Func dialect. This commit removes a
large majority of then, greatly reducing the dependence surface area of the
Func dialect.
The last remaining operations in the standard dialect all revolve around
FuncOp/function related constructs. This patch simply handles the initial
renaming (which by itself is already huge), but there are a large number
of cleanups unlocked/necessary afterwards:
* Removing a bunch of unnecessary dependencies on Func
* Cleaning up the From/ToStandard conversion passes
* Preparing for the move of FuncOp to the Func dialect
See the discussion at https://discourse.llvm.org/t/standard-dialect-the-final-chapter/6061
Differential Revision: https://reviews.llvm.org/D120624
This reduces the dependencies of the MLIRVector target and makes the dialect consistent with other dialects.
Differential Revision: https://reviews.llvm.org/D118533
This has been a major TODO for a very long time, and is necessary for establishing a proper
dialect-free dependency layering for the Transforms library. Code was moved to effectively
two main locations:
* Affine/
There was quite a bit of affine dialect related code in Transforms/ do to historical reasons
(of a time way into MLIR's past). The following headers were moved to:
Transforms/LoopFusionUtils.h -> Dialect/Affine/LoopFusionUtils.h
Transforms/LoopUtils.h -> Dialect/Affine/LoopUtils.h
Transforms/Utils.h -> Dialect/Affine/Utils.h
The following transforms were also moved:
AffineLoopFusion, AffinePipelineDataTransfer, LoopCoalescing
* SCF/
Only one SCF pass was in Transforms/ (likely accidentally placed here): ParallelLoopCollapsing
The SCF specific utilities in LoopUtils have been moved to SCF/Utils.h
* Misc:
mlir::moveLoopInvariantCode was also moved to LoopLikeInterface.h given
that it is a simple utility defined in terms of LoopLikeOpInterface.
Differential Revision: https://reviews.llvm.org/D117848
The current state of the top level Analysis/ directory is that it contains two libraries;
a generic Analysis library (free from dialect dependencies), and a LoopAnalysis library
that contains various analysis utilities that originated from Affine loop transformations.
This commit moves the LoopAnalysis to the more appropriate home of `Dialect/Affine/Analysis/`,
given the use and intention of the majority of the code within it. After the move, if there
are generic utilities that would fit better in the top-level Analysis/ directory, we can move
them.
Differential Revision: https://reviews.llvm.org/D117351
After removing the range type, Linalg does not define any type. The revision thus consolidates the LinalgOps.h and LinalgTypes.h into a single Linalg.h header. Additionally, LinalgTypes.cpp is renamed to LinalgDialect.cpp to follow the convention adopted by other dialects such as the tensor dialect.
Depends On D115727
Reviewed By: nicolasvasilache
Differential Revision: https://reviews.llvm.org/D115728
Precursor: https://reviews.llvm.org/D110200
Removed redundant ops from the standard dialect that were moved to the
`arith` or `math` dialects.
Renamed all instances of operations in the codebase and in tests.
Reviewed By: rriddle, jpienaar
Differential Revision: https://reviews.llvm.org/D110797
This revision extracts padding hoisting in a new file and cleans it up in prevision of future improvements and extensions.
Differential Revision: https://reviews.llvm.org/D110414
* Add batched version of all `addId` variants, so that multiple IDs can be added at a time.
* Rename `addId` and variants to `insertId` and `appendId`. Most external users call `appendId`. Splitting `addId` into two functions also makes it possible to provide batched version for both. (Otherwise, the overloads are ambigious when calling `addId`.)
Differential Revision: https://reviews.llvm.org/D108532
* Rename ids to values in FlatAffineValueConstraints.
* Overall cleanup of comments in FlatAffineConstraints and FlatAffineValueConstraints.
Differential Revision: https://reviews.llvm.org/D107947
