The recently introduced support for generating MLIR Operations with optional
attributes did not handle the formatted string emission properly, in particular
it did not escape `{` and `}` in calls to `formatv` leading to assertions
during TableGen op definition generation. Fix this by splitting out the
unncessary braces from the format string. Additionally, fix the emission of
the builder argument comment to correctly indicate which attributes are indeed
optional and which are not.
PiperOrigin-RevId: 236832230
The only reason in starting with a fixedpoint add is that it is the absolute simplest variant and illustrates the level of abstraction I'm aiming for.
The overall flow would be:
1. Determine quantization parameters (out of scope of this cl).
2. Source dialect rules to lower supported math ops to the quantization dialect (out of scope of this cl).
3. Quantization passes: [-quant-convert-const, -quant-lower-uniform-real-math, -quant-lower-unsupported-to-float] (the last one not implemented yet)
4. Target specific lowering of the integral arithmetic ops (roughly at the level of gemmlowp) to more fundamental operations (i.e. calls to gemmlowp, simd instructions, DSP instructions, etc).
How I'm doing this should facilitate implementation of just about any kind of backend except TFLite, which has a very course, adhoc surface area for its quantized kernels. Options there include (I'm not taking an opinion on this - just trying to provide options):
a) Not using any of this: just match q/dbarrier + tf math ops to the supported TFLite quantized op set.
b) Implement the more fundamental integer math ops on TFLite and convert to those instead of the current op set.
Note that I've hand-waved over the process of choosing appropriate quantization parameters. Getting to that next. As you can see, different implementations will likely have different magic combinations of specific math support, and we will need the target system that has been discussed for some of the esoteric cases (i.e. many DSPs only support POT fixedpoint).
Two unrelated changes to the overall goal of this CL and can be broken out of desired:
- Adding optional attribute support to TabelGen
- Allowing TableGen native rewrite hooks to return nullptr, signalling that no rewrite has been done.
PiperOrigin-RevId: 235267229
* Introduce a OpTrait class in C++ to wrap the TableGen definition;
* Introduce PredOpTrait and rename previous usage of OpTrait to NativeOpTrait;
* PredOpTrait allows specifying a trait of the operation by way of predicate on the operation. This will be used in future to create reusable set of trait building blocks in the definition of operations. E.g., indicating whether to operands have the same type and allowing locally documenting op requirements by trait composition.
- Some of these building blocks could later evolve into known fixed set as LLVMs backends do, but that can be considered with more data.
* Use the modelling to address one verify TODO in a very local manner.
This subsumes the current custom verify specification which will be removed in a separate mechanical CL.
PiperOrigin-RevId: 234827169
This CL extended TableGen Operator class to provide accessors for information on op
results.
In OpDefinitionGen, added checks to make sure only the last result can be variadic,
and adjusted traits and builders generation to consider variadic results.
PiperOrigin-RevId: 234596124
The parameter to emitStandaloneParamBuilder() was renamed from hasResultType to
isAllSameType, which is the opposite boolean value. The logic should be changed
to make them consistent.
Also re-ordered some methods in Operator. And few other tiny improvements.
PiperOrigin-RevId: 234478316
We specify op operands and results in TableGen op definition using the same syntax.
They should be modelled similarly in TableGen driver wrapper classes.
PiperOrigin-RevId: 234153332
For ops with the SameOperandsAndResultType trait, we know that all result types
should be the same as the first operand's type. So we can generate a build()
method without requiring result types as parameters and also invoke this method
when constructing such ops during expanding rewrite patterns.
Similarly for ops have broadcast behavior, we can define build() method to use
the deduced type as the result type. So we can also calling into this build()
method when constructing ops in RewriterGen.
PiperOrigin-RevId: 233988307
* Add tf.LeakyRelu op definition + folders (well one is really canonicalizer)
* Change generated error message to use attribute description instead;
* Change the return type of F32Attr to be APFloat - internally it is already
stored as APFloat so let the caller decides if they want to convert it or
not. I could see varying opinions here though :) (did not change i32attr
similarly)
PiperOrigin-RevId: 232923358
Previously, we were using the trait mechanism to specify that an op has variadic operands.
That led a discrepancy between how we handle ops with deterministic number of operands.
Besides, we have no way to specify the constraints and match against the variadic operands.
This CL introduced Variadic<Type> as a way to solve the above issues.
PiperOrigin-RevId: 232656104
They are essentially both modelling MLIR OpTrait; the former achieves the
purpose via introducing corresponding symbols in TableGen, while the latter
just uses plain strings.
Unify them to provide a single mechanism to avoid confusion and to better
reflect the definitions on MLIR C++ side.
Ideally we should be able to deduce lots of these traits automatically via
other bits of op definitions instead of manually specifying them; but not
for now though.
PiperOrigin-RevId: 232191401
Similar to op operands and attributes, use DAG to specify operation's results.
This will allow us to provide names and matchers for outputs.
Also Defined `outs` as a marker to indicate the start of op result list.
PiperOrigin-RevId: 231422455
canonicalizations of operations. The ultimate important user of this is
going to be a funcBuilder->foldOrCreate<YourOp>(...) API, but for now it
is just a more convenient way to write certain classes of canonicalizations
(see the change in StandardOps.cpp).
NFC.
PiperOrigin-RevId: 230770021
Add default values to attributes, to allow attribute being left unspecified. The attr getter will always return an attribute so callers need not check for it, if the attribute is not set then the default will be returned (at present the default will be constructed upon query but this will be changed).
Add op definition for tf.AvgPool in ops.td, rewrite matcher using pattern using attribute matching & transforms. Adding some helper functions to make it simpler.
Handle attributes with dialect prefix and map them to getter without dialect prefix.
Note: VerifyAvgPoolOp could probably be autogenerated by know given the predicate specification on attributes, but deferring that to a follow up.
PiperOrigin-RevId: 230364857
Start doc generation pass that generates simple markdown output. The output is formatted simply[1] in markdown, but this allows seeing what info we have, where we can refine the op description (e.g., the inputs is probably redundant), what info is missing (e.g., the attributes could probably have a description).
The formatting of the description is still left up to whatever was in the op definition (which luckily, due to the uniformity in the .td file, turned out well but relying on the indentation there is fragile). The mechanism to autogenerate these post changes has not been added yet either. The output file could be run through a markdown formatter too to remove extra spaces.
[1]. This is not proposal for final style :) There could also be a discussion around single doc vs multiple (per dialect, per op), whether we want a TOC, whether operands/attributes should be headings or just formatted differently ...
PiperOrigin-RevId: 230354538
Change MinMaxAttr to match hasValidMinMaxAttribute behavior. Post rewriting the other users of that function it could be removed too. The currently generated error message is:
error: 'tfl.fake_quant' op attribute 'minmax' failed to satisfy constraint of MinMaxAttr
PiperOrigin-RevId: 229775631
Start simple with single predicate match & transform rules for attributes.
* Its unclear whether modelling Attr predicates will be needed so start with allowing matching attributes with a single predicate.
* The input and output attr type often differs and so add ability to specify a transform between the input and output format.
PiperOrigin-RevId: 229580879
MLIR has support for type-polymorphic instructions, i.e. instructions that may
take arguments of different types. For example, standard arithmetic operands
take scalars, vectors or tensors. In order to express such instructions in
TableGen, we need to be able to verify that a type object satisfies certain
constraints, but we don't need to construct an instance of this type. The
existing TableGen definition of Type requires both. Extract out a
TypeConstraint TableGen class to define restrictions on types. Define the Type
TableGen class as a subclass of TypeConstraint for consistency. Accept records
of the TypeConstraint class instead of the Type class as values in the
Arguments class when defining operators.
Replace the predicate logic TableGen class based on conjunctive normal form
with the predicate logic classes allowing for abitrary combinations of
predicates using Boolean operators (AND/OR/NOT). The combination is
implemented using simple string rewriting of C++ expressions and, therefore,
respects the short-circuit evaluation order. No logic simplification is
performed at the TableGen level so all expressions must be valid C++.
Maintaining CNF using TableGen only would have been complicated when one needed
to introduce top-level disjunction. It is also unclear if it could lead to a
significantly simpler emitted C++ code. In the future, we may replace inplace
predicate string combination with a tree structure that can be simplified in
TableGen's C++ driver.
Combined, these changes allow one to express traits like ArgumentsAreFloatLike
directly in TableGen instead of relying on C++ trait classes.
PiperOrigin-RevId: 229398247
* Check was returning success instead of failure when reporting illegal type;
* TFL ops only support tensor types so update tests with corrected logic.
- Removed some checks in broadcasting that don't work with tensor input requirement;
PiperOrigin-RevId: 228770184
This CL added a tblgen::Attribute class to wrap around raw TableGen
Record getValue*() calls on Attr defs, which will provide a nicer
API for handling TableGen Record.
PiperOrigin-RevId: 228581107
Bind attributes similar to operands. Use to rewrite leakyreulo and const rewrite pattern. The attribute type/attributes are not currently checked so should only be used where the attributes match due to the construction of the op.
To support current attribute namespacing, convert __ in attribute name to "$" for matching purposes ('$' is not valid character in variable in TableGen).
Some simplification to make it simpler to specify indented ostream and avoid so many spaces. The goal is not to have perfectly formatted code generated but good enough so that its still easy to read for a user.
PiperOrigin-RevId: 228183639
Expand type to include matcher predicates. Use CNF form to allow specifying combinations of constraints for type. The matching call for the type is used to verify the construction of the operation as well as in rewrite pattern generation.
The matching initially includes redundant checks (e.g., even if the operand of the op is guaranteed to satisfy some requirement, it is still checked during matcher generation for now). As well as some of the traits specified now check what the generated code already checks. Some of the traits can be removed in future as the verify method will include the relevant checks based on the op definition already.
More work is needed for variadic operands.
CNF form is used so that in the follow up redundant checks in the rewrite patterns could be omitted (e.g., when matching a F32Tensor, one does not need to verify that op X's operand 0 is a Tensor if that is guaranteed by op X's definition). The alternative was to have single matcher function specified, but this would not allow for reasoning about what attributes already hold (at the level of PredAtoms).
Use this new operand type restrictions to rewrite BiasAdd with floating point operands as declarative pattern.
PiperOrigin-RevId: 227991412
Use tablegen to generate definitions of the standard binary arithmetic
operations. These operations share a lot of boilerplate that is better off
generated by a tool.
Using tablegen for standard binary arithmetic operations requires the following
modifications.
1. Add a bit field `hasConstantFolder` to the base Op tablegen class; generate
the `constantFold` method signature if the bit is set. Differentiate between
single-result and zero/multi-result functions that use different signatures.
The implementation of the method remains in C++, similarly to canonicalization
patterns, since it may be large and non-trivial.
2. Define the `AnyType` record of class `Type` since `BinaryOp` currently
provided in op_base.td is supposed to operate on tensors and other tablegen
users may rely on this behavior.
Note that this drops the inline documentation on the operation classes that was
copy-pasted around anyway. Since we don't generate g3doc from tablegen yet,
keep LangRef.md as it is. Eventually, the user documentation can move to the
tablegen definition file as well.
PiperOrigin-RevId: 227820815
Add ops.td for TF dialect and start by adding tf.Add (op used in legalizer pattern). This CL does not add TensorOp trait (that's not part of OpTrait namespace).
Remove OpCode emission that is not currently used and can be added back later if needed.
PiperOrigin-RevId: 227590973
StmtResult -> InstResult, StmtOperand -> InstOperand, and remove the old names.
This is step 17/n towards merging instructions and statements, NFC.
PiperOrigin-RevId: 227121537
is the new base of the SSA value hierarchy. This CL also standardizes all the
nomenclature and comments to use 'Value' where appropriate. This also eliminates a large number of cast<MLValue>(x)'s, which is very soothing.
This is step 11/n towards merging instructions and statements, NFC.
PiperOrigin-RevId: 227064624
River Riddle