Deprecate the `match` and `rewrite` functions. They mainly exist for
historic reasons. This PR also updates all remaining uses of in the MLIR
codebase.
This is addressing a
[comment](https://github.com/llvm/llvm-project/pull/129861#pullrequestreview-2662696084)
on an earlier PR.
Note for LLVM integration: `SplitMatchAndRewrite` will be deleted soon,
update your patterns to use `matchAndRewrite` instead of separate
`match` / `rewrite`.
---------
Co-authored-by: Jakub Kuderski <jakub@nod-labs.com>
The vast majority of rewrite / conversion patterns uses a combined
`matchAndRewrite` instead of separate `match` and `rewrite` functions.
This PR optimizes the code base for the most common case where users
implement a combined `matchAndRewrite`. There are no longer any `match`
and `rewrite` functions in `RewritePattern`, `ConversionPattern` and
their derived classes. Instead, there is a `SplitMatchAndRewriteImpl`
class that implements `matchAndRewrite` in terms of `match` and
`rewrite`.
Details:
* The `RewritePattern` and `ConversionPattern` classes are simpler
(fewer functions). Especially the `ConversionPattern` class, which now
has 5 fewer functions. (There were various `rewrite` overloads to
account for 1:1 / 1:N patterns.)
* There is a new class `SplitMatchAndRewriteImpl` that derives from
`RewritePattern` / `OpRewritePatern` / ..., along with a type alias
`RewritePattern::SplitMatchAndRewrite` for convenience.
* Fewer `llvm_unreachable` are needed throughout the code base. Instead,
we can use pure virtual functions. (In cases where users previously had
to implement `rewrite` or `matchAndRewrite`, etc.)
* This PR may also improve the number of [`-Woverload-virtual`
warnings](https://discourse.llvm.org/t/matchandrewrite-hiding-virtual-functions/84933)
that are produced by GCC. (To be confirmed...)
Note for LLVM integration: Patterns with separate `match` / `rewrite`
implementations, must derive from `X::SplitMatchAndRewrite` instead of
`X`.
---------
Co-authored-by: River Riddle <riddleriver@gmail.com>
The greedy rewriter is used in many different flows and it has a lot of
convenience (work list management, debugging actions, tracing, etc). But
it combines two kinds of greedy behavior 1) how ops are matched, 2)
folding wherever it can.
These are independent forms of greedy and leads to inefficiency. E.g.,
cases where one need to create different phases in lowering and is
required to applying patterns in specific order split across different
passes. Using the driver one ends up needlessly retrying folding/having
multiple rounds of folding attempts, where one final run would have
sufficed.
Of course folks can locally avoid this behavior by just building their
own, but this is also a common requested feature that folks keep on
working around locally in suboptimal ways.
For downstream users, there should be no behavioral change. Updating
from the deprecated should just be a find and replace (e.g., `find ./
-type f -exec sed -i
's|applyPatternsAndFoldGreedily|applyPatternsGreedily|g' {} \;` variety)
as the API arguments hasn't changed between the two.
This PR fixes typos within documentation in various files.
Most changes are trivial. The one interesting change is the
documentation for `custom<X>` in `assemblyFormat` that used the wrong
return type. The return type from the `parseX` function should be
`ParseResult` rather than `LogicalResult`. The `ParseResult` type is
necessary due to tablegen generating code like the following within an
Op `parse()` function:
```
auto odsResult = parseInferredArrayType(parser, elementsTypes, elementsOperands, resultRawTypes[0]);
if (odsResult) return ::mlir::failure();
```
This will fail to compile if `parseInferredArrayType()` returns
`LogicalResult`. See also `parsePrettyLLVMType()` in LLVMTypes.h,
`parseSingleBlockRegion()` in IRDL.cpp, `parseDynamicIndexList()` in
ViewLikeInterface.cpp, etc.
This is intended as a fast pattern rewrite driver for the cases when a
simple walk gets the job done but we would still want to implement it in
terms of rewrite patterns (that can be used with the greedy pattern
rewrite driver downstream).
The new driver is inspired by the discussion in
https://github.com/llvm/llvm-project/pull/112454 and the LLVM Dev
presentation from @matthias-springer earlier this week.
This limitation comes with some limitations:
* It does not repeat until a fixpoint or revisit ops modified in place
or newly created ops. In general, it only walks forward (in the
post-order).
* `matchAndRewrite` can only erase the matched op or its descendants.
This is verified under expensive checks.
* It does not perform folding / DCE.
We could probably relax some of these in the future without sacrificing
too much performance.
I double checked the links by building [the
website](https://github.com/llvm/mlir-www):
```
$ mlir-www-helper.sh --install-docs ../llvm-project website
$ cd website && hugo serve
```
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`).
This renaming started with the native ODS support for properties, this is completing it.
A mass automated textual rename seems safe for most codebases.
Drop also the ods prefix to keep the accessors the same as they were before
this change:
properties.odsOperandSegmentSizes
reverts back to:
properties.operandSegementSizes
The ODS prefix was creating divergence between all the places and make it harder to
be consistent.
Reviewed By: jpienaar
Differential Revision: https://reviews.llvm.org/D157173
Deduplicate large parts of the worklist processing (`GreedyPatternRewriteDriver::processWorklist`).
The new class hierarchy is as follows:
```
GreedyPatternRewriteDriver (abstract)
^
|
-----------------------------------
| |
RegionPatternRewriteDriver MultiOpPatternRewriteDriver
```
Also update the Markdown documentation.
Differential Revision: https://reviews.llvm.org/D141396
This reland includes changes to the Python bindings.
Switch variadic operand and result segment size attributes to use the
dense i32 array. Dense integer arrays were introduced primarily to
represent index lists. They are a better fit for segment sizes than
dense elements attrs.
Depends on D131801
Reviewed By: rriddle
Differential Revision: https://reviews.llvm.org/D131803
Switch variadic operand and result segment size attributes to use the
dense i32 array. Dense integer arrays were introduced primarily to
represent index lists. They are a better fit for segment sizes than
dense elements attrs.
Depends on D131738
Reviewed By: mehdi_amini
Differential Revision: https://reviews.llvm.org/D131702
The constructor of PatternApplicator doesn't have a constructor that
accepts only a `RewritePatternSet` as currently used in the example
code in PatternRewriter.md. Instead, one has to turn it into a
`FrozenRewritePatternSet`.
Reviewed By: nicolasvasilache
Differential Revision: https://reviews.llvm.org/D125236
ListOption currently uses llvm:🆑:list under the hood, but the usages
of ListOption are generally a tad different from llvm:🆑:list. This
commit codifies this by making ListOption implicitly comma separated,
and removes the explicit flag set for all of the current list options.
The new parsing for comma separation of ListOption also adds in support
for skipping over delimited sub-ranges (i.e. {}, [], (), "", ''). This
more easily supports nested options that use those as part of the
format, and this constraint (balanced delimiters) is already codified
in the syntax of pass pipelines.
See https://discourse.llvm.org/t/list-of-lists-pass-option/5950 for
related discussion
Differential Revision: https://reviews.llvm.org/D122879
This effectively mirrors the logging in dialect conversion, which has proven
very useful for understanding the pattern application process.
Differential Revision: https://reviews.llvm.org/D112120
This revision allows for attaching "debug labels" to patterns, and provides to FrozenRewritePatternSet for filtering patterns based on these labels (in addition to the debug name of the pattern). This will greatly simplify the ability to write tests targeted towards specific patterns (in cases where many patterns may interact), will also simplify debugging pattern application by observing how application changes when enabling/disabling specific patterns.
To enable better reuse of pattern rewrite options between passes, this revision also adds a new PassUtil.td file to the Rewrite/ library that will allow for passes to easily hook into a common interface for pattern debugging. Two options are used to seed this utility, `disable-patterns` and `enable-patterns`, which are used to enable the filtering behavior indicated above.
Differential Revision: https://reviews.llvm.org/D102441
This is the fourth and final patch in a series of patches fixing markdown links and references inside the mlir documentation. This patch combined with the other three should fix almost every broken link on mlir.llvm.org as far as I can tell.
This patch in particular addresses all Markdown files in the top level docs directory.
Differential Revision: https://reviews.llvm.org/D103032
This is a hook that allows for providing custom initialization of the pattern, e.g. if it has bounded recursion, setting the debug name, etc., without needing to define a custom constructor. A non-virtual hook was chosen to avoid polluting the vtable with code that we really just want to be inlined when constructing the pattern. The alternative to this would be to just define a constructor for each pattern, this unfortunately creates a lot of otherwise unnecessary boiler plate for a lot of patterns and a hook provides a much simpler/cleaner interface for the very common case.
Differential Revision: https://reviews.llvm.org/D102440
We currently do not document how the pattern rewriter infra treats recursion when it gets detected. This revision adds a blurb on recursion in patterns, and how patterns can signal that they are equipped to handle it.
Differential Revision: https://reviews.llvm.org/D102439
This doesn't change APIs, this just cleans up the many in-tree uses of these
names to use the new preferred names. We'll keep the old names around for a
couple weeks to help transitions.
Differential Revision: https://reviews.llvm.org/D99127
The Pattern class was originally intended to be used for solely matching operations, but that use never materialized. All of the pattern infrastructure uses RewritePattern, and the infrastructure for pure matching(Matchers.h) is implemented inline. This means that this class isn't a useful abstraction at the moment, so this revision refactors it to solely encapsulate the "metadata" of a pattern. The metadata includes the various state describing a pattern; benefit, root operation, etc. The API on PatternApplicator is updated to now operate on `Pattern`s as nothing special from `RewritePattern` is necessary.
This refactoring is also necessary for the upcoming use of PDL patterns alongside C++ rewrite patterns.
Differential Revision: https://reviews.llvm.org/D86258
This infrastructure has evolved a lot over the course of MLIRs lifetime, and has never truly been documented outside of rationale or proposals. This revision aims to document the infrastructure and user facing API, with the rationale specific portions moved to the Rationale folder and updated.
Differential Revision: https://reviews.llvm.org/D85260
