38 Commits

Author SHA1 Message Date
Fangrui Song
7557530f42 [mlir] Fix duplicate word typos; NFC
Those fixes were taken from https://reviews.llvm.org/D137338
2023-09-01 20:53:08 -07:00
Mogball
b49bb7bdec [MLIR][PDL] Add support for representing and lowering negated constraints
This commit enables modelling negation of native constraints.

This is accomplished through an attribute `isNegated` on the operations `pdl.apply_native_constraint` and `pdl_interp.apply_constraint` and according adjustments to the conversion in the ConvertPDLToPDLInterpPass.

Reviewed By: Mogball

Differential Revision: https://reviews.llvm.org/D153871
2023-08-24 17:47:48 +00:00
Tres Popp
68f58812e3 [mlir] Move casting calls from methods to function calls
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.

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 patch updates all remaining uses of the deprecated functionality in
mlir/. This was done with clang-tidy as described below and further
modifications to GPUBase.td and OpenMPOpsInterfaces.td.

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:
   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.

```
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
```

Differential Revision: https://reviews.llvm.org/D151542
2023-05-26 10:29:55 +02:00
Tres Popp
5550c82189 [mlir] Move casting calls from methods to function calls
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
2023-05-12 11:21:25 +02:00
Ramkumar Ramachandra
22426110c5 mlir/tblgen: use std::optional in generation
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
2022-12-17 11:13:26 +01:00
Kazu Hirata
1a36588ec6 [mlir] Use std::nullopt instead of None (NFC)
This patch mechanically replaces None with std::nullopt where the
compiler would warn if None were deprecated.  The intent is to reduce
the amount of manual work required in migrating from Optional to
std::optional.

This is part of an effort to migrate from llvm::Optional to
std::optional:

https://discourse.llvm.org/t/deprecating-llvm-optional-x-hasvalue-getvalue-getvalueor/63716
2022-12-03 18:50:27 -08:00
River Riddle
ce57789d8e [mlir:PDL] Add support for creating ranges in rewrites
This commit adds support for building a concatenated range from
a given set of elements, either single element or other ranges, within a
rewrite. We could conceptually extend this to support constraining
input ranges, but the logic there is quite a bit more complex so it is
left for later work when a need arises.

Differential Revision: https://reviews.llvm.org/D133719
2022-11-08 01:57:57 -08:00
River Riddle
8c66344ee9 [mlir:PDL] Add support for DialectConversion with pattern configurations
Up until now PDL(L) has not supported dialect conversion because we had no
way of remapping values or integrating with type conversions. This commit
rectifies that by adding a new "pattern configuration" concept to PDL. This
essentially allows for attaching external configurations to patterns, which
can hook into pattern events (for now just the scope of a rewrite, but we
could also pass configs to native rewrites as well). This allows for injecting
the type converter into the conversion pattern rewriter.

Differential Revision: https://reviews.llvm.org/D133142
2022-11-08 01:57:57 -08:00
River Riddle
310c3ee472 [mlir:PDL][NFC] Update PDL API to use prefixed accessors
This doesn't flip the switch for prefix generation yet, that'll be
done in a followup.
2022-09-30 15:27:10 -07:00
River Riddle
72fddfb599 [mlir] Flip PDL to use Both accessors
This allows for incrementally updating the old API usages without
needing to update everything at once. PDL will be left on Both
for a little bit and then flipped to prefixed when all APIs have been
updated.

Differential Revision: https://reviews.llvm.org/D134387
2022-09-21 17:36:13 -07:00
River Riddle
b69f10f5a1 [mlir][PDL] Infer result types from a replace as the last resort
This prevents situations where explicit results types were provided,
which have different types than the operation being replaced. This
is useful for supporting dialect conversion, which will have proper
support added in a followup.

Differential Revision: https://reviews.llvm.org/D133141
2022-09-08 11:35:31 -07:00
Michele Scuttari
67d0d7ac0a
[MLIR] Update pass declarations to new autogenerated files
The patch introduces the required changes to update the pass declarations and definitions to use the new autogenerated files and allow dropping the old infrastructure.

Reviewed By: mehdi_amini, rriddle

Differential Review: https://reviews.llvm.org/D132838
2022-08-31 12:28:45 +02:00
Michele Scuttari
039b969b32
Revert "[MLIR] Update pass declarations to new autogenerated files"
This reverts commit 2be8af8f0e0780901213b6fd3013a5268ddc3359.
2022-08-30 22:21:55 +02:00
Michele Scuttari
2be8af8f0e
[MLIR] Update pass declarations to new autogenerated files
The patch introduces the required changes to update the pass declarations and definitions to use the new autogenerated files and allow dropping the old infrastructure.

Reviewed By: mehdi_amini, rriddle

Differential Review: https://reviews.llvm.org/D132838
2022-08-30 21:56:31 +02:00
River Riddle
3c75228991 [mlir:PDLInterp] Refactor the implementation of result type inferrence
The current implementation uses a discrete "pdl_interp.inferred_types"
operation, which acts as a "fake" handle to a type range. This op is
used as a signal to pdl_interp.create_operation that types should be
inferred. This is terribly awkward and clunky though:

* This op doesn't have a byte code representation, and its conversion
  to bytecode kind of assumes that it is only used in a certain way. The
  current lowering is also broken and seemingly untested.

* Given that this is a different operation, it gives off the assumption
  that it can be used multiple times, or that after the first use
  the value contains the inferred types. This isn't the case though,
  the resultant type range can never actually be used as a type range.

This commit refactors the representation by removing the discrete
InferredTypesOp, and instead adds a UnitAttr to
pdl_interp.CreateOperation that signals when the created operations
should infer their types. This leads to a much much cleaner abstraction,
a more optimal bytecode lowering, and also allows for better error
handling and diagnostics when a created operation doesn't actually
support type inferrence.

Differential Revision: https://reviews.llvm.org/D124587
2022-05-01 12:25:05 -07:00
River Riddle
9595f3568a [mlir:PDL] Remove the ConstantParams support from native Constraints/Rewrites
This support has never really worked well, and is incredibly clunky to
use (it effectively creates two argument APIs), and clunky to generate (it isn't
clear how we should actually expose this from PDL frontends). Treating these
as just attribute arguments is much much cleaner in every aspect of the stack.
If we need to optimize lots of constant parameters, it would be better to
investigate internal representation optimizations (e.g. batch attribute creation),
that do not affect the user (we want a clean external API).

Differential Revision: https://reviews.llvm.org/D121569
2022-03-19 13:28:24 -07:00
River Riddle
3c405c3b9b [mlir:PDLInterp][NFC] Switch to using prefixed accessors
PDLInterp is effectively an internal dialect, so there isn't a need to
stage the switch.
2022-03-15 17:36:36 -07:00
River Riddle
f96a8675cd [mlir][PDL] Define a new PDLInterp::FuncOp operation and drop uses of FuncOp
Defining our own function operation allows for the PDL interpreter
to be more self contained, and also removes any dependency on FuncOp;
which is moving out of the Builtin dialect.

Differential Revision: https://reviews.llvm.org/D121253
2022-03-15 14:55:51 -07:00
River Riddle
e084679f96 [mlir] Make locations required when adding/creating block arguments
BlockArguments gained the ability to have locations attached a while ago, but they
have always been optional. This goes against the core tenant of MLIR where location
information is a requirement, so this commit updates the API to require locations.

Fixes #53279

Differential Revision: https://reviews.llvm.org/D117633
2022-01-19 17:35:35 -08:00
Benjamin Kramer
41760a6b40 [mlir] Make Value's constructor constexpr. NFCI.
This allows clang to flag unused Values in more cases, so remove them.
2022-01-04 21:04:13 +01:00
Uday Bondhugula
80b3f08eee [MLIR[PDL] NFC. Fix unused variable warning in PDLToPDLInterp.cpp
NFC. Fix unused variable warning in PDLToPDLInterp.cpp.

Differential Revision: https://reviews.llvm.org/D116571
2022-01-04 08:25:02 +05:30
Stanislav Funiak
2692eae574 [MLIR][PDL] Refactor the positions for multi-root patterns.
When the original version of multi-root patterns was reviewed, several improvements were made to the pdl_interp operations during the review process. Specifically, the "get users of a value at the specified operand index" was split up into "get users" and "compare the users' operands with that value". The iterative execution was also cleaned up to `pdl_interp.foreach`. However, the positions in the pdl-to-pdl_interp lowering were not similarly refactored. This introduced several problems, including hard-to-detect bugs in the lowering and duplicate evaluation of `pdl_interp.get_users`.

This diff cleans up the positions. The "upward" `OperationPosition` was split-out into `UsersPosition` and `ForEachPosition`, and the operand comparison was replaced with a simple predicate. In the process, I fixed three bugs:
1. When multiple roots were had the same connector (i.e., a node that they shared with a subtree at the previously visited root), we would generate a single foreach loop rather than one foreach loop for each such root. The reason for this is that such connectors shared the position. The solution for this is to add root index as an id to the newly introduced `ForEachPosition`.
2. Previously, we would use `pdl_interp.get_operands` indiscriminately, whether or not the operand was variadic. We now correctly detect variadic operands and insert `pdl_interp.get_operand` when needed.
3. In certain corner cases, we would trigger the "connector has not been traversed yet" assertion. This was caused by not inserting the values during the upward traversal correctly. This has now been fixed.

Reviewed By: Mogball

Differential Revision: https://reviews.llvm.org/D116080
2022-01-04 08:03:44 +05:30
Mehdi Amini
e4853be2f1 Apply clang-tidy fixes for performance-for-range-copy to MLIR (NFC) 2022-01-02 22:19:56 +00:00
River Riddle
233e9476d8 [mlir:PDL] Allow non-bound pdl.attribute/pdl.type operations that create constants
This allows for passing in these attributes/types to constraints/rewrites as arguments.

Differential Revision: https://reviews.llvm.org/D114817
2021-12-10 19:38:43 +00:00
Mehdi Amini
be0a7e9f27 Adjust "end namespace" comment in MLIR to match new agree'd coding style
See D115115 and this mailing list discussion:
https://lists.llvm.org/pipermail/llvm-dev/2021-December/154199.html

Differential Revision: https://reviews.llvm.org/D115309
2021-12-08 06:05:26 +00:00
Stanislav Funiak
a19e163526 Fixed broken build under GCC 5.4.
This diff fixes broken build caused by D108550. Under GCC 5, auto lambdas that capture this require `this->` for member calls.

Reviewed By: bondhugula

Differential Revision: https://reviews.llvm.org/D114659
2021-11-27 09:03:27 +05:30
Stanislav Funiak
a76ee58f3c Multi-root PDL matching using upward traversals.
This is commit 4 of 4 for the multi-root matching in PDL, discussed in https://llvm.discourse.group/t/rfc-multi-root-pdl-patterns-for-kernel-matching/4148 (topic flagged for review).

This PR integrates the various components (root ordering algorithm, nondeterministic execution of PDL bytecode) to implement multi-root PDL matching. The main idea is for the pattern to specify mulitple candidate roots. The PDL-to-PDLInterp lowering selects one of these roots and "hangs" the pattern from this root, traversing the edges downwards (from operation to its operands) when possible and upwards (from values to its uses) when needed. The root is selected by invoking the optimal matching multiple times, once for each candidate root, and the connectors are determined form the optimal matching. The costs in the directed graph are equal to the number of upward edges that need to be traversed when connecting the given two candidate roots. It can be shown that, for this choice of the cost function, "hanging" the pattern an inner node is no better than from the optimal root.

The following three main additions were implemented as a part of this PR:
1. OperationPos predicate has been extended to allow tracing the operation accepting a value (the opposite of operation defining a value).
2. Predicate checking if two values are not equal - this is useful to ensure that we do not traverse the edge back downwards after we traversed it upwards.
3. Function for for building the cost graph among the candidate roots.
4. Updated buildPredicateList, building the predicates optimal branching has been determined.

Testing: unit tests (an integration test to follow once the stack of commits has landed)

Reviewed By: rriddle

Differential Revision: https://reviews.llvm.org/D108550
2021-11-26 18:11:37 +05:30
Chris Lattner
faf1c22408 [Builder] Eliminate the StringRef/StringAttr forms of getSymbolRefAttr.
The StringAttr version doesn't need a context, so we can just use the
existing `SymbolRefAttr::get` form.  The StringRef version isn't preferred
so we want to encourage people to use StringAttr.

There is an additional form of getSymbolRefAttr that takes a (SymbolTrait
implementing) operation.  This should also be moved, but I'll do that as
a separate patch.

Differential Revision: https://reviews.llvm.org/D108922
2021-08-30 16:05:36 -07:00
Guillaume Chatelet
1d49e5352f [llvm] remove Sequence::asSmallVector()
There's no need for `toSmallVector()` as `SmallVector.h` already provides a `to_vector` free function that takes a range.

Reviewed By: Quuxplusone

Differential Revision: https://reviews.llvm.org/D104024
2021-06-14 08:28:05 +00:00
Guillaume Chatelet
e0569033e2 [llvm] Make Sequence reverse-iterable
This is a roll forward of D102679.
This patch simplifies the implementation of Sequence and makes it compatible with llvm::reverse.
It exposes the reverse iterators through rbegin/rend which prevents a dangling reference in std::reverse_iterator::operator++().

Note: Compared to D102679, this patch introduces a `asSmallVector()` member function and fixes compilation issue with GCC 5.

Differential Revision: https://reviews.llvm.org/D103948
2021-06-10 11:15:28 +00:00
Mehdi Amini
a4e2cf712a Revert "[llvm] Make Sequence reverse-iterable"
This reverts commit e772216e708937988c039420d2c559568f91ae27
(and fixup 7f6c878a2c035eb6325ab228d9bc2d257509d959).

The build is broken with gcc5 host compiler:

In file included from
                 from mlir/lib/Dialect/Utils/StructuredOpsUtils.cpp:9:
tools/mlir/include/mlir/IR/BuiltinAttributes.h.inc:424:57: error: type/value mismatch at argument 1 in template parameter list for 'template<class ItTy, class FuncTy, class FuncReturnTy> class llvm::mapped_iterator'
                               std::function<T(ptrdiff_t)>>;
                                                         ^
tools/mlir/include/mlir/IR/BuiltinAttributes.h.inc:424:57: note:   expected a type, got 'decltype (seq<ptrdiff_t>(0, 0))::const_iterator'
2021-06-08 17:03:10 +00:00
Guillaume Chatelet
e772216e70 [llvm] Make Sequence reverse-iterable
This patch simplifies the implementation of Sequence and makes it compatible with llvm::reverse.
It exposes the reverse iterators through rbegin/rend which prevents a dangling reference in std::reverse_iterator::operator++().

Differential Revision: https://reviews.llvm.org/D102679
2021-06-08 13:18:57 +00:00
River Riddle
4efb7754e0 [mlir][NFC] Add a using directive for llvm::SetVector
Differential Revision: https://reviews.llvm.org/D100436
2021-04-15 16:09:34 -07:00
River Riddle
3a833a0e0e [mlir][PDL] Add support for variadic operands and results in the PDL Interpreter
This revision extends the PDL Interpreter dialect to add support for variadic operands and results, with ranges of these values represented via the recently added !pdl.range type. To support this extension, three new operations have been added that closely match the single variant:
* pdl_interp.check_types : Compare a range of types with a known range.
* pdl_interp.create_types : Create a constant range of types.
* pdl_interp.get_operands : Get a range of operands from an operation.
* pdl_interp.get_results : Get a range of results from an operation.
* pdl_interp.switch_types : Switch on a range of types.

This revision handles adding support in the interpreter dialect and the conversion from PDL to PDLInterp. Support for variadic operands and results in the bytecode will be added in a followup revision.

Differential Revision: https://reviews.llvm.org/D95722
2021-03-16 13:20:19 -07:00
River Riddle
02c4c0d5b2 [mlir][pdl] Remove CreateNativeOp in favor of a more general ApplyNativeRewriteOp.
This has a numerous amount of benefits, given the overly clunky nature of CreateNativeOp:
* Users can now call into arbitrary rewrite functions from inside of PDL, allowing for more natural interleaving of PDL/C++ and enabling for more of the pattern to be in PDL.
* Removes the need for an additional set of C++ functions/registry/etc. The new ApplyNativeRewriteOp will use the same PDLRewriteFunction as the existing RewriteOp. This reduces the API surface area exposed to users.

This revision also introduces a new PDLResultList class. This class is used to provide results of native rewrite functions back to PDL. We introduce a new class instead of using a SmallVector to simplify the work necessary for variadics, given that ranges will require some changes to the structure of PDLValue.

Differential Revision: https://reviews.llvm.org/D95720
2021-03-16 13:20:18 -07:00
River Riddle
242762c9a3 [mlir][pdl] Restructure how results are represented.
Up until now, results have been represented as additional results to a pdl.operation. This is fairly clunky, as it mismatches the representation of the rest of the IR constructs(e.g. pdl.operand) and also isn't a viable representation for operations returned by pdl.create_native. This representation also creates much more difficult problems when factoring in support for variadic result groups, optional results, etc. To resolve some of these problems, and simplify adding support for variable length results, this revision extracts the representation for results out of pdl.operation in the form of a new `pdl.result` operation. This operation returns the result of an operation at a given index, e.g.:

```
%root = pdl.operation ...
%result = pdl.result 0 of %root
```

Differential Revision: https://reviews.llvm.org/D95719
2021-03-16 13:20:18 -07:00
Christian Sigg
c4a0405902 Add Operation* OpState::operator->() to provide more convenient access to members of Operation.
Given that OpState already implicit converts to Operator*, this seems reasonable.

The alternative would be to add more functions to OpState which forward to Operation.

Reviewed By: rriddle, ftynse

Differential Revision: https://reviews.llvm.org/D92266
2020-12-02 15:46:20 +01:00
River Riddle
8a1ca2cd34 [mlir] Add a conversion pass between PDL and the PDL Interpreter Dialect
The conversion between PDL and the interpreter is split into several different parts.
** The Matcher:

The matching section of all incoming pdl.pattern operations is converted into a predicate tree and merged. Each pattern is first converted into an ordered list of predicates starting from the root operation. A predicate is composed of three distinct parts:
* Position
  - A position refers to a specific location on the input DAG, i.e. an
    existing MLIR entity being matched. These can be attributes, operands,
    operations, results, and types. Each position also defines a relation to
    its parent. For example, the operand `[0] -> 1` has a parent operation
    position `[0]` (the root).
* Question
  - A question refers to a query on a specific positional value. For
  example, an operation name question checks the name of an operation
  position.
* Answer
  - An answer is the expected result of a question. For example, when
  matching an operation with the name "foo.op". The question would be an
  operation name question, with an expected answer of "foo.op".

After the predicate lists have been created and ordered(based on occurrence of common predicates and other factors), they are formed into a tree of nodes that represent the branching flow of a pattern match. This structure allows for efficient construction and merging of the input patterns. There are currently only 4 simple nodes in the tree:
* ExitNode: Represents the termination of a match
* SuccessNode: Represents a successful match of a specific pattern
* BoolNode/SwitchNode: Branch to a specific child node based on the expected answer to a predicate question.

Once the matcher tree has been generated, this tree is walked to generate the corresponding interpreter operations.

 ** The Rewriter:
The rewriter portion of a pattern is generated in a very straightforward manor, similarly to lowerings in other dialects. Each PDL operation that may exist within a rewrite has a mapping into the interpreter dialect. The code for the rewriter is generated within a FuncOp, that is invoked by the interpreter on a successful pattern match. Referenced values defined in the matcher become inputs the generated rewriter function.

An example lowering is shown below:

```mlir
// The following high level PDL pattern:
pdl.pattern : benefit(1) {
  %resultType = pdl.type
  %inputOperand = pdl.input
  %root, %results = pdl.operation "foo.op"(%inputOperand) -> %resultType
  pdl.rewrite %root {
    pdl.replace %root with (%inputOperand)
  }
}

// is lowered to the following:
module {
  // The matcher function takes the root operation as an input.
  func @matcher(%arg0: !pdl.operation) {
    pdl_interp.check_operation_name of %arg0 is "foo.op" -> ^bb2, ^bb1
  ^bb1:
    pdl_interp.return
  ^bb2:
    pdl_interp.check_operand_count of %arg0 is 1 -> ^bb3, ^bb1
  ^bb3:
    pdl_interp.check_result_count of %arg0 is 1 -> ^bb4, ^bb1
  ^bb4:
    %0 = pdl_interp.get_operand 0 of %arg0
    pdl_interp.is_not_null %0 : !pdl.value -> ^bb5, ^bb1
  ^bb5:
    %1 = pdl_interp.get_result 0 of %arg0
    pdl_interp.is_not_null %1 : !pdl.value -> ^bb6, ^bb1
  ^bb6:
    // This operation corresponds to a successful pattern match.
    pdl_interp.record_match @rewriters::@rewriter(%0, %arg0 : !pdl.value, !pdl.operation) : benefit(1), loc([%arg0]), root("foo.op") -> ^bb1
  }
  module @rewriters {
    // The inputs to the rewriter from the matcher are passed as arguments.
    func @rewriter(%arg0: !pdl.value, %arg1: !pdl.operation) {
      pdl_interp.replace %arg1 with(%arg0)
      pdl_interp.return
    }
  }
}
```

Differential Revision: https://reviews.llvm.org/D84580
2020-10-26 18:01:06 -07:00