From https://reviews.llvm.org/D153245
This adds support for native PDL (and PDLL) C++ constraints to return
results.
This is useful for situations where a pattern checks for certain
constraints of multiple interdependent attributes and computes a new
attribute value based on them. Currently, for such an example it is
required to escape to C++ during matching to perform the check and after
a successful match again escape to native C++ to perform the computation
during the rewriting part of the pattern. With this work we can do the
computation in C++ during matching and use the result in the rewriting
part of the pattern. Effectively this enables a choice in the trade-off
of memory consumption during matching vs recomputation of values.
This is an example of a situation where this is useful: We have two
operations with certain attributes that have interdependent constraints.
For instance `attr_foo: one_of [0, 2, 4, 8], attr_bar: one_of [0, 2, 4,
8]` and `attr_foo == attr_bar`. The pattern should only match if all
conditions are true. The new operation should be created with a new
attribute which is computed from the two matched attributes e.g.
`attr_baz = attr_foo * attr_bar`. For the check we already escape to
native C++ and have all values at hand so it makes sense to directly
compute the new attribute value as well:
```
Constraint checkAndCompute(attr0: Attr, attr1: Attr) -> Attr;
Pattern example with benefit(1) {
let foo = op<test.foo>() {attr = attr_foo : Attr};
let bar = op<test.bar>(foo) {attr = attr_bar : Attr};
let attr_baz = checkAndCompute(attr_foo, attr_bar);
rewrite bar with {
let baz = op<test.baz> {attr=attr_baz};
replace bar with baz;
};
}
```
To achieve this the following notable changes were necessary:
PDLL:
- Remove check in PDLL parser that prevented native constraints from
returning results
PDL:
- Change PDL definition of pdl.apply_native_constraint to allow variadic
results
PDL_interp:
- Change PDL_interp definition of pdl_interp.apply_constraint to allow
variadic results
PDLToPDLInterp Pass:
The input to the pass is an arbitrary number of PDL patterns. The pass
collects the predicates that are required to match all of the pdl
patterns and establishes an ordering that allows creation of a single
efficient matcher function to match all of them. Values that are matched
and possibly used in the rewriting part of a pattern are represented as
positions. This allows fusion and thus reusing a single position for
multiple matching patterns. Accordingly, we introduce
ConstraintPosition, which records the type and index of the result of
the constraint. The problem is for the corresponding value to be used in
the rewriting part of a pattern it has to be an input to the
pdl_interp.record_match operation, which is generated early during the
pass such that its surrounding block can be referred to by branching
operations. In consequence the value has to be materialized after the
original pdl.apply_native_constraint has been deleted but before we get
the chance to generate the corresponding pdl_interp.apply_constraint
operation. We solve this by emitting a placeholder value when a
ConstraintPosition is evaluated. These placeholder values (due to fusion
there may be multiple for one constraint result) are replaced later when
the actual pdl_interp.apply_constraint operation is created.
Changes since the phabricator review:
- Addressed all comments
- In particular, removed registerConstraintFunctionWithResults and
instead changed registerConstraintFunction so that contraint functions
always have results (empty by default)
- Thus we don't need to reuse `rewriteFunctions` to store constraint
functions with results anymore, and can instead use
`constraintFunctions`
- Perform a stable sort of ConstraintQuestion, so that
ConstraintQuestion appear before other ConstraintQuestion that use their
results.
- Don't create placeholders for pdl_interp::ApplyConstraintOp. Instead
generate the `pdl_interp::ApplyConstraintOp` before generating the
successor block.
- Fixed a test failure in the pdl python bindings
Original code by @martin-luecke
Co-authored-by: martin-luecke <martinpaul.luecke@amd.com>
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 follows a previous patch that updated calls
`op.cast<T>()-> cast<T>(op)`. However some cases could not handle an
unprefixed `cast` call due to occurrences of variables named cast, or
occurring inside of class definitions which would resolve to the method.
All C++ files that did not work automatically with `cast<T>()` are
updated here to `llvm::cast` and similar with the intention that they
can be easily updated after the methods are removed through a
find-replace.
See https://github.com/llvm/llvm-project/compare/main...tpopp:llvm-project:tidy-cast-check
for the clang-tidy check that is used and then update printed
occurrences of the function to include `llvm::` before.
One can then run the following:
```
ninja -C $BUILD_DIR clang-tidy
run-clang-tidy -clang-tidy-binary=$BUILD_DIR/bin/clang-tidy -checks='-*,misc-cast-functions'\
-export-fixes /tmp/cast/casts.yaml mlir/*\
-header-filter=mlir/ -fix
rm -rf $BUILD_DIR/tools/mlir/**/*.inc
```
Differential Revision: https://reviews.llvm.org/D150348
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
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
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
We currently emit an error during verification if a pdl.operation with non-inferrable
results is used within a rewrite. This allows for catching some errors during compile
time, but is slightly broken. For one, the verification at the PDL level assumes that
all dialects have been loaded, which is true at run time, but may not be true when
the PDL is generated (such as via PDLL). This commit fixes this by not emitting the
error if the operation isn't registered, i.e. it uses the `mightHave` variant of trait/interface
methods.
Secondly, we currently don't verify when a pdl.operation has no explicit results, but the
operation being created is known to expect at least one. This commit adds a heuristic
error to detect these cases when possible and fail. We can't always capture when the user
made an error, but we can capture the most common case where the user expected an
operation to infer its result types (when it actually isn't possible).
Differential Revision: https://reviews.llvm.org/D124583
I am not sure about the meaning of Type in the name (was it meant be interpreted as Kind?), and given the importance and meaning of Type in the context of MLIR, its probably better to rename it. Given the comment in the source code, the suggestion in the GitHub issue and the final discussions in the review, this patch renames the OperandType to UnresolvedOperand.
Fixes https://github.com/llvm/llvm-project/issues/54446
Differential Revision: https://reviews.llvm.org/D122142
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
In this CL, update the function name of verifier according to the
behavior. If a verifier needs to access the region then it'll be updated
to `verifyRegions`.
Reviewed By: rriddle
Differential Revision: https://reviews.llvm.org/D120373
PDLDialect being a somewhat user-facing dialect and whose ops contain exclusively other PDL ops in their regions can take advantage of `OpAsmOpInterface` to provide nicer IR.
Reviewed By: rriddle
Differential Revision: https://reviews.llvm.org/D117828
Presently the result type verification checks if the type is used by a `pdl::OperationOp` inside the matcher. This is unnecessarily restrictive; the type could come from a `pdl::OperandOp or `pdl::OperandsOp` and still be inferrable.
Reviewed By: rriddle, Mogball
Differential Revision: https://reviews.llvm.org/D116083
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
The current implementation is quite clunky; OperationName stores either an Identifier
or an AbstractOperation that corresponds to an operation. This has several problems:
* OperationNames created before and after an operation are registered are different
* Accessing the identifier name/dialect/etc. from an OperationName are overly branchy
- they need to dyn_cast a PointerUnion to check the state
This commit refactors this such that we create a single information struct for every
operation name, even operations that aren't registered yet. When an OperationName is
created for an unregistered operation, we only populate the name field. When the
operation is registered, we populate the remaining fields. With this we now have two
new classes: OperationName and RegisteredOperationName. These both point to the
same underlying operation information struct, but only RegisteredOperationName can
assume that the operation is actually registered. This leads to a much cleaner API, and
we can also move some AbstractOperation functionality directly to OperationName.
Differential Revision: https://reviews.llvm.org/D114049
* Previously, we were only generating .h.inc files. We foresee the need to also generate implementations and this is a step towards that.
* Discussed in https://llvm.discourse.group/t/generating-cpp-inc-files-for-dialects/3732/2
* Deviates from the discussion above by generating a default constructor in the .cpp.inc file (and adding a tablegen bit that disables this in case if this is user provided).
* Generating the destructor started as a way to flush out the missing includes (produces a link error), but it is a strict improvement on its own that is worth doing (i.e. by emitting key methods in the .cpp file, we root vtables in one translation unit, which is a non-controversial improvement).
Differential Revision: https://reviews.llvm.org/D105070
This revision extends the PDL 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.operands : Define a range of input operands.
* pdl.results : Extract a result group from an operation.
* pdl.types : Define a handle to a range of types.
Support for these in the pdl interpreter dialect and byte code will be added in followup revisions.
Differential Revision: https://reviews.llvm.org/D95721
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
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
This allows for storage instances to store data that isn't uniqued in the context, or contain otherwise non-trivial logic, in the rare situations that they occur. Storage instances with trivial destructors will still have their destructor skipped. A consequence of this is that the storage instance definition must be visible from the place that registers the type.
Differential Revision: https://reviews.llvm.org/D98311
This better matches the actual IR concept that is being modeled, and is consistent with how the rest of PDL is structured.
Differential Revision: https://reviews.llvm.org/D95718
This type represents a range of positional values. It will be used in followup revisions to add support for variadic constructs to PDL, such as operand and result ranges.
Differential Revision: https://reviews.llvm.org/D95717
This is part of a larger refactoring the better congregates the builtin structures under the BuiltinDialect. This also removes the problematic "standard" naming that clashes with the "standard" dialect, which is not defined within IR/. A temporary forward is placed in StandardTypes.h to allow time for downstream users to replaced references.
Differential Revision: https://reviews.llvm.org/D92435
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
Now backends spell out which namespace they want to be in, instead of relying on
clients #including them inside already-opened namespaces. This also means that
cppNamespaces should be fully qualified, and there's no implicit "::mlir::"
prepended to them anymore.
Reviewed By: mehdi_amini
Differential Revision: https://reviews.llvm.org/D86811
The PDL Interpreter dialect provides a lower level abstraction compared to the PDL dialect, and is targeted towards low level optimization and interpreter code generation. The dialect operations encapsulates low-level pattern match and rewrite "primitives", such as navigating the IR (Operation::getOperand), creating new operations (OpBuilder::create), etc. Many of the operations within this dialect also fuse branching control flow with some form of a predicate comparison operation. This type of fusion reduces the amount of work that an interpreter must do when executing.
An example of this representation 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)
}
}
// May be represented in the interpreter dialect as follows:
module {
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:
pdl_interp.record_match @rewriters::@rewriter(%0, %arg0 : !pdl.value, !pdl.operation) : benefit(1), loc([%arg0]), root("foo.op") -> ^bb1
}
module @rewriters {
func @rewriter(%arg0: !pdl.value, %arg1: !pdl.operation) {
pdl_interp.replace %arg1 with(%arg0)
pdl_interp.return
}
}
}
```
Differential Revision: https://reviews.llvm.org/D84579
PDL presents a high level abstraction for the rewrite pattern infrastructure available in MLIR. This abstraction allows for representing patterns transforming MLIR, as MLIR. This allows for applying all of the benefits that the general MLIR infrastructure provides, to the infrastructure itself. This means that pattern matching can be more easily verified for correctness, targeted by frontends, and optimized.
PDL abstracts over various different aspects of patterns and core MLIR data structures. Patterns are specified via a `pdl.pattern` operation. These operations contain a region body for the "matcher" code, and terminate with a `pdl.rewrite` that either dispatches to an external rewriter or contains a region for the rewrite specified via `pdl`. The types of values in `pdl` are handle types to MLIR C++ types, with `!pdl.attribute`, `!pdl.operation`, and `!pdl.type` directly mapping to `mlir::Attribute`, `mlir::Operation*`, and `mlir::Value` respectively.
An example pattern is shown below:
```mlir
// pdl.pattern contains metadata similarly to a `RewritePattern`.
pdl.pattern : benefit(1) {
// External input operand values are specified via `pdl.input` operations.
// Result types are constrainted via `pdl.type` operations.
%resultType = pdl.type
%inputOperand = pdl.input
%root, %results = pdl.operation "foo.op"(%inputOperand) -> %resultType
pdl.rewrite(%root) {
pdl.replace %root with (%inputOperand)
}
}
```
This is a culmination of the work originally discussed here: https://groups.google.com/a/tensorflow.org/g/mlir/c/j_bn74ByxlQ
Differential Revision: https://reviews.llvm.org/D84578
