Commit Graph

152 Commits

Author SHA1 Message Date
River Riddle c6c534493d Port all of the existing passes over to the new pass manager infrastructure. This is largely NFC.
PiperOrigin-RevId: 235952357
2019-03-29 16:47:14 -07:00
Alex Zinenko 486dde42c0 EDSC: move FileCheck tests into the source file
EDSC provide APIs for constructing and modifying the IR.  These APIs are
currently tested by a "test" module pass that reads the dummy IR (empty
functions), recognizes certain function names and injects the IR into those
functions based on their name.  This situation is unsatisfactory because the
expected outcome of the test lives in a different file than the input to the
test, i.e. the API calls.

Create a new binary for tests that constructs the IR from scratch using EDSC
APIs and prints it.  Put FileCheck comments next to the printing.  This removes
the need to have a file with dummy inputs and assert on its contents in the
test driver.  The test source includes a simplistic test harness that runs all
functions marked as TEST_FUNC but intentionally does not include any
value-testing functionality.

PiperOrigin-RevId: 235886629
2019-03-29 16:46:10 -07:00
Nicolas Vasilache 62c54a2ec4 Add a stripmineSink and imperfectly nested tiling primitives.
This CL adds a primitive to perform stripmining of a loop by a given factor and
sinking it under multiple target loops.
In turn this is used to implement imperfectly nested loop tiling (with interchange) by repeatedly calling the stripmineSink primitive.

The API returns the point loops and allows repeated invocations of tiling to achieve declarative, multi-level, imperfectly-nested tiling.

Note that this CL is only concerned with the mechanical aspects and does not worry about analysis and legality.

The API is demonstrated in an example which creates an EDSC block, emits the corresponding MLIR and applies imperfectly-nested tiling:

```cpp
    auto block = edsc::block({
      For(ArrayRef<edsc::Expr>{i, j}, {zero, zero}, {M, N}, {one, one}, {
        For(k1, zero, O, one, {
          C({i, j, k1}) = A({i, j, k1}) + B({i, j, k1})
        }),
        For(k2, zero, O, one, {
          C({i, j, k2}) = A({i, j, k2}) + B({i, j, k2})
        }),
      }),
    });
    // clang-format on
    emitter.emitStmts(block.getBody());

    auto l_i = emitter.getAffineForOp(i), l_j = emitter.getAffineForOp(j),
         l_k1 = emitter.getAffineForOp(k1), l_k2 = emitter.getAffineForOp(k2);
    auto indicesL1 = mlir::tile({l_i, l_j}, {512, 1024}, {l_k1, l_k2});
    auto l_ii1 = indicesL1[0][0], l_jj1 = indicesL1[1][0];
    mlir::tile({l_jj1, l_ii1}, {32, 16}, l_jj1);
```

The edsc::Expr for the induction variables (i, j, k_1, k_2) provide the programmatic hooks from which tiling can be applied declaratively.

PiperOrigin-RevId: 235548228
2019-03-29 16:41:20 -07:00
Alex Zinenko e7193a70f8 EDSC: support conditional branch instructions
Leverage the recently introduced support for multiple argument groups and
multiple destination blocks in EDSC Expressions to implement conditional
branches in EDSC.  Conditional branches have two successors and three argument
groups.  The first group contains a single expression of i1 type that
corresponds to the condition of the branch.  The two following groups contain
arguments of the two successors of the conditional branch instruction, in the
same order as the successors.  Expose this instruction to the C API and Python
bindings.

PiperOrigin-RevId: 235542768
2019-03-29 16:41:05 -07:00
Alex Zinenko 83e8db2193 EDSC: support branch instructions
The new implementation of blocks was designed to support blocks with arguments.
More specifically, StmtBlock can be constructed with a list of Bindables that
will be bound to block aguments upon construction.  Leverage this functionality
to implement branch instructions with arguments.

This additionally requires the statement storage to have a list of successors,
similarly to core IR operations.

Becauase successor chains can form loops, we need a possibility to decouple
block declaration, after which it becomes usable by branch instructions, from
block body definition.  This is achieved by creating an empty block and by
resetting its body with a new list of instructions.  Note that assigning a
block from another block will not affect any instructions that may have
designated this block as their successor (this behavior is necessary to make
value-type semantics of EDSC types consistent).  Combined, one can now write
generators like

    EDSCContext context;
    Type indexType = ...;
    Bindable i(indexType), ii(indexType), zero(indexType), one(indexType);
    StmtBlock loopBlock({i}, {});
    loopBlock.set({ii = i + one,
                   Branch(loopBlock, {ii})});
    MLIREmitter(&builder)
        .bindConstant<ConstantIndexOp>(zero, 0)
        .bindConstant<ConstantIndexOp>(one, 1)
	.emitStmt(Branch(loopBlock, {zero}));

where the emitter will emit the statement and its successors, if present.

PiperOrigin-RevId: 235541892
2019-03-29 16:40:50 -07:00
Alex Zinenko ec76f9c8c1 EDSC printing: handle integer attributes with bitwidth > 64
This came up in post-submit review.  Use LLVM's support for outputting APInt
values directly instead of obtaining a 64-bit integer value from APInt, which
will not work for wider integers.

PiperOrigin-RevId: 235531574
2019-03-29 16:40:05 -07:00
River Riddle 3e656599f1 Define a PassID class to use when defining a pass. This allows for the type used for the ID field to be self documenting. It also allows for the compiler to know the set alignment of the ID object, which is useful for storing pointer identifiers within llvm data structures.
PiperOrigin-RevId: 235107957
2019-03-29 16:37:12 -07:00
Sergei Lebedev 1cc9305c71 Exposed division and remainder operations in EDSC
This change introduces three new operators in EDSC: Div (also exposed
via Expr.__div__ aka /) -- floating-point division, FloorDiv and CeilDiv
for flooring/ceiling index division.

The lowering to LLVM will be implemented in b/124872679.

PiperOrigin-RevId: 234963217
2019-03-29 16:36:41 -07:00
Alex Zinenko 59a209721e EDSC: support call instructions
Introduce support for binding MLIR functions as constant expressions.  Standard
constant operation supports functions as possible constant values.

Provide C APIs to look up existing named functions in an MLIR module and expose
them to the Python bindings.  Provide Python bindings to declare a function in
an MLIR module without defining it and to add a definition given a function
declaration.  These declarations are useful when attempting to link MLIR
modules with, e.g., the standard library.

Introduce EDSC support for direct and indirect calls to other MLIR functions.
Internally, an indirect call is always emitted to leverage existing support for
delayed construction of MLIR Values using EDSC Exprs.  If the expression is
bound to a constant function (looked up or declared beforehand), MLIR constant
folding will be able to replace an indirect call by a direct call.  Currently,
only zero- and one-result functions are supported since we don't have support
for multi-valued expressions in EDSC.

Expose function calling interface to Python bindings on expressions by defining
a `__call__` function accepting a variable number of arguments.

PiperOrigin-RevId: 234959444
2019-03-29 16:36:26 -07:00
Jacques Pienaar 5162c58c78 Fix unused errors in opt build.
PiperOrigin-RevId: 234841678
2019-03-29 16:35:55 -07:00
Alex Zinenko 0cc24bb1af EDSC: emit composed affine maps again
The recent rework of MLIREmitter switched to using the generic call to
`builder.createOperation` from OperationState instead of individual customized
calls to `builder.create<>`.  As a result, regular non-composed affine apply
operations where emitted.  Introduce a special case in Expr::build to always
create composed affine maps instead, as it used to be the case before the
rework.

Such special-casing goes against the idea of EDSC generality and extensibility.
Instead, we should consider declaring the composed form canonical for
affine.apply operations and using the builder support for creating operations
and canonicalizing them immediately (ongoing effort).

PiperOrigin-RevId: 234790129
2019-03-29 16:34:26 -07:00
Alex Zinenko 21bd4540f3 EDSC: introduce min/max only usable inside for upper/lower bounds of a loop
Introduce a type-safe way of building a 'for' loop with max/min bounds in EDSC.
Define new types MaxExpr and MinExpr in C++ EDSC API and expose them to Python
bindings.  Use values of these type to construct 'for' loops with max/min in
newly introduced overloads of the `edsc::For` factory function.  Note that in C
APIs, we still must expose MaxMinFor as a different function because C has no
overloads.  Also note that MaxExpr and MinExpr do _not_ derive from Expr
because they are not allowed to be used in a regular Expr context (which may
produce `affine.apply` instructions not expecting `min` or `max`).

Factory functions `Min` and `Max` in Python can be further overloaded to
produce chains of comparisons and selects on non-index types.  This is not
trivial in C++ since overloaded functions cannot differ by the return type only
(`MaxExpr` or `Expr`) and making `MaxExpr` derive from `Expr` defies the
purpose of type-safe construction.

PiperOrigin-RevId: 234786131
2019-03-29 16:34:11 -07:00
Alex Zinenko d055a4e100 EDSC: support multi-expression loop bounds
MLIR supports 'for' loops with lower(upper) bound defined by taking a
maximum(minimum) of a list of expressions, but does not have first-class affine
constructs for the maximum(minimum).  All these expressions must have affine
provenance, similarly to a single-expression bound.  Add support for
constructing such loops using EDSC.  The expression factory function is called
`edsc::MaxMinFor` to (1) highlight that the maximum(minimum) operation is
applied to the lower(upper) bound expressions and (2) differentiate it from a
`edsc::For` that creates multiple perfectly nested loops (and should arguably
be called `edsc::ForNest`).

PiperOrigin-RevId: 234785996
2019-03-29 16:33:56 -07:00
Alex Zinenko a2a433652d EDSC: create constants as expressions
Introduce a functionality to create EDSC expressions from typed constants.
This complements the current functionality that uses "unbound" expressions and
binds them to a specific constant before emission.  It comes in handy in cases
where we want to check if something is a constant early during construciton
rather than late during emission, for example multiplications and divisions in
affine expressions.  This is also consistent with MLIR vision of constants
being defined by an operation (rather than being special kinds of values in the
IR) by exposing this operation as EDSC expression.

PiperOrigin-RevId: 234758020
2019-03-29 16:33:41 -07:00
Nicolas Vasilache ffdf98d092 [EDSC] Fix Stmt::operator= and allow DimOp in For loops
This CL fixes 2 recent issues with EDSCs:
1. the type of the LHS in Stmt::operator=(Expr rhs) should be the same as the (asserted unique) return type;
2. symbols coming from DimOp should be admissible as lower / upper bounds in For

The relevant tests are added.

PiperOrigin-RevId: 234750249
2019-03-29 16:33:26 -07:00
River Riddle 48ccae2476 NFC: Refactor the files related to passes.
* PassRegistry is split into its own source file.
* Pass related files are moved to a new library 'Pass'.

PiperOrigin-RevId: 234705771
2019-03-29 16:32:56 -07:00
Nicolas Vasilache 25016dc4c6 [EDSC] Remove dead code in MLIREmitter.cpp
cl/234609882 made EDSCs typed on construction (instead of typed on emission).
This CL cleans up some leftover dead code.

PiperOrigin-RevId: 234627105
2019-03-29 16:32:26 -07:00
Alex Zinenko 05f37d52d0 EDSC: clean up type casting mechanism
Originally, edsc::Expr had a long enum edsc::ExprKind with all supported types
of operations.  Recent Expr extensibility support removed the need to specify
supported types in advance.  Replace the no-longer-used blocks of enum values
reserved for unary/binary/ternary/variadic expressions with simple values (it
is still useful to know if an expression is, e.g., binary to access it through
a simpler API).

Furthermore, wrap string-comparison now used to identify specific ops into an
`Expr::is_op<>` function template, that acts similarly to `Instruction::isa<>`.
Introduce `{Unary,Binary,Ternary,Variadic}Expr::make<> ` function template that
creates a Expression emitting the MLIR Op specified as template argument.

PiperOrigin-RevId: 234612916
2019-03-29 16:31:41 -07:00
Alex Zinenko b4dba895a6 EDSC: make Expr typed and extensible
Expose the result types of edsc::Expr, which are now stored for all types of
Exprs and not only for the variadic ones.  Require return types when an Expr is
constructed, if it will ever have some.  An empty return type list is
interpreted as an Expr that does not create a value (e.g. `return` or `store`).

Conceptually, all edss::Exprs are now typed, with the type being a (potentially
empty) tuple of return types.  Unbound expressions and Bindables must now be
constructed with a specific type they will take.  This makes EDSC less
evidently type-polymorphic, but we can still write generic code such as

    Expr sumOfSquares(Expr lhs, Expr rhs) { return lhs * lhs + rhs * rhs; }

and use it to construct different typed expressions as

    sumOfSquares(Bindable(IndexType::get(ctx)), Bindable(IndexType::get(ctx)));
    sumOfSquares(Bindable(FloatType::getF32(ctx)),
                 Bindable(FloatType::getF32(ctx)));

On the positive side, we get the following.
1. We can now perform type checking when constructing Exprs rather than during
   MLIR emission.  Nevertheless, this is still duplicates the Op::verify()
   until we can factor out type checking from that.
2. MLIREmitter is significantly simplified.
3. ExprKind enum is only used for actual kinds of expressions.  Data structures
   are converging with AbstractOperation, and the users can now create a
   VariadicExpr("canonical_op_name", {types}, {exprs}) for any operation, even
   an unregistered one without having to extend the enum and make pervasive
   changes to EDSCs.

On the negative side, we get the following.
1. Typed bindables are more verbose, even in Python.
2. We lose the ability to do print debugging for higher-level EDSC abstractions
   that are implemented as multiple MLIR Ops, for example logical disjunction.

This is the step 2/n towards making EDSC extensible.

***

Move MLIR Op construction from MLIREmitter::emitExpr to Expr::build since Expr
now has sufficient information to build itself.

This is the step 3/n towards making EDSC extensible.

Both of these strive to minimize the amount of irrelevant changes.  In
particular, this introduces more complex pretty-printing for affine and binary
expression to make sure tests continue to pass.  It also relies on string
comparison to identify specific operations that an Expr produces.

PiperOrigin-RevId: 234609882
2019-03-29 16:31:26 -07:00
Alex Zinenko 0a4c940c1b EDSC: introduce support for blocks
EDSC currently implement a block as a statement that is itself a list of
statements.  This suffers from two modeling problems: (1) these blocks are not
addressable, i.e. one cannot create an instruction where thus constructed block
is a successor; (2) they support block nesting, which is not supported by MLIR
blocks.  Furthermore, emitting such "compound statement" (misleadingly named
`Block` in Python bindings) does not actually produce a new Block in the IR.

Implement support for creating actual IR Blocks in EDSC.  In particular, define
a new StmtBlock EDSC class that is neither an Expr nor a Stmt but contains a
list of Stmts.  Additionally, StmtBlock may have (early-) typed arguments.
These arguments are Bindable expressions that can be used inside the block.
Provide two calls in the MLIREmitter, `emitBlock` that actually emits a new
block and `emitBlockBody` that only emits the instructions contained in the
block without creating a new block.  In the latter case, the instructions must
not use block arguments.

Update Python bindings to make it clear when instruction emission happens
without creating a new block.

PiperOrigin-RevId: 234556474
2019-03-29 16:30:56 -07:00
Alex Zinenko ecd403c0e8 EDSC: properly construct FunctionTypes
The existing implementation of makeFunctionType in EDSC contains a bug: the
array of input types is overwritten using output types passed as arguments and
the array of output types is never filled in.  This leads to all sorts of
incorrect memory behavior.  Fill in the array of output types using the proper
argument.

PiperOrigin-RevId: 234177221
2019-03-29 16:29:56 -07:00
Alex Zinenko f2c93f0995 EDSC: fix unused-wariable warning when compiling without assertions
In LowerEDSCTestPass, there are two range-for loops that only do assertions on
the loop variable.  With assertions disabled, the variable becomes unused and
triggers a warning promoted to error.  Cast it to void in the loop to supress
the warning.

PiperOrigin-RevId: 233936171
2019-03-29 16:27:25 -07:00
Alex Zinenko bc184cff3f EDSC: unify Expr storage
EDSC expressions evolved to have different types of underlying storage.
Separate classes are used for unary, binary, ternary and variadic expressions.
The latter covers all the needs of the three special cases.  Remove these
special cases and use a single ExprStorage class everywhere while maintaining
the same APIs at the Expr level (ExprStorage is an internal implementation
class).

This is step 1/n to converging EDSC expressions and Ops and making EDSCs
support custom operations.

PiperOrigin-RevId: 233704912
2019-03-29 16:26:37 -07:00
River Riddle 4755774d16 Make IndexType a standard type instead of a builtin. This also cleans up some unnecessary factory methods on the Type class.
PiperOrigin-RevId: 233640730
2019-03-29 16:25:38 -07:00
Alex Zinenko 0e59e5c49b EDSC: move Expr and Stmt construction operators to a namespace
In the current state, edsc::Expr and edsc::Stmt overload operators to construct
other Exprs and Stmts.  This includes some unconventional overloads of the
`operator==` to create a comparison expression and of the `operator!` to create
a negation expression.  This situation could lead to unpleasant surprises where
the code does not behave like expected.  Make all Expr and Stmt construction
operators free functions and move them to the `edsc::op` namespace.  Callers
willing to use these operators must explicitly include them with the `using`
declaration.  This can be done in some local scope.

Additionally, we currently emit signed comparisons for order-comparison
operators.  With namespaces, we can later introduce two sets of operators in
different namespace, e.g. `edsc::op::sign` and `edsc::op::unsign` to clearly
state which kind of comparison is implied.

PiperOrigin-RevId: 233578674
2019-03-29 16:25:08 -07:00
Alex Zinenko ed81ddc865 EDSC: support 'for' loops with dynamic bounds
The existing implementation in EDSC of 'for' loops in MLIREmitter is
unnecessarily restricted to constant bounds.  The underlying AffineForOp can be
constructed from (a list of) Values and AffineMaps instead of constants.  Its
verifier will check that the "affine provenance" conditions, i.e. that the
values used in the loop conditions are defined in such a way that they can be
analyzed by affine passes, are respected.  One can use non-constant values in
affine loop bounds in conjunction with a single-dimensional identity affine
map.  Implement this in MLIREmitter while maintaining the special case for
constant bounds that leads to significantly simpler generated IR when
applicable.

Test this change using the EDSC lowering test pass to inject code emitted from
EDSC into functions with predefined names.

PiperOrigin-RevId: 233578220
2019-03-29 16:24:53 -07:00
Sergei Lebedev 52ec65c85e Implemented __eq__ and __ne__ in EDSC Python bindings
PiperOrigin-RevId: 232473201
2019-03-29 16:13:34 -07:00
River Riddle bf9c381d1d Remove InstWalker and move all instruction walking to the api facilities on Function/Block/Instruction.
PiperOrigin-RevId: 232388113
2019-03-29 16:12:59 -07:00
River Riddle 44e040dd63 Remove remaining references to OperationInst in all directories except for lib/Transforms.
PiperOrigin-RevId: 232322771
2019-03-29 16:10:38 -07:00
River Riddle a3d9ccaecb Replace the walkOps/visitOperationInst variants from the InstWalkers with the Instruction variants.
PiperOrigin-RevId: 232322030
2019-03-29 16:10:24 -07:00
Dimitrios Vytiniotis 9ca0691b06 Exposing logical operators in EDSC all the way up to Python.
PiperOrigin-RevId: 232299839
2019-03-29 16:10:08 -07:00
River Riddle de2d0dfbca Fold the functionality of OperationInst into Instruction. OperationInst still exists as a forward declaration and will be removed incrementally in a set of followup cleanup patches.
PiperOrigin-RevId: 232198540
2019-03-29 16:09:19 -07:00
River Riddle 5052bd8582 Define the AffineForOp and replace ForInst with it. This patch is largely mechanical, i.e. changing usages of ForInst to OpPointer<AffineForOp>. An important difference is that upon construction an AffineForOp no longer automatically creates the body and induction variable. To generate the body/iv, 'createBody' can be called on an AffineForOp with no body.
PiperOrigin-RevId: 232060516
2019-03-29 16:06:49 -07:00
Nicolas Vasilache 0353ef99eb Cleanup EDSCs and start a functional auto-generated library of custom Ops
This CL applies the following simplifications to EDSCs:
1. Rename Block to StmtList because an MLIR Block is a different, not yet
supported, notion;
2. Rework Bindable to drop specific storage and just use it as a simple wrapper
around Expr. The only value of Bindable is to force a static cast when used by
the user to bind into the emitter. For all intended purposes, Bindable is just
a lightweight check that an Expr is Unbound. This simplifies usage and reduces
the API footprint. After playing with it for some time, it wasn't worth the API
cognition overhead;
3. Replace makeExprs and makeBindables by makeNewExprs and copyExprs which is
more explicit and less easy to misuse;
4. Add generally useful functionality to MLIREmitter:
  a. expose zero and one for the ubiquitous common lower bounds and step;
  b. add support to create already bound Exprs for all function arguments as
  well as shapes and views for Exprs bound to memrefs.
5. Delete Stmt::operator= and replace by a `Stmt::set` method which is more
explicit.
6. Make Stmt::operator Expr() explicit.
7. Indexed.indices assertions are removed to pave the way for expressing slices
and views as well as to work with 0-D memrefs.

The CL plugs those simplifications with TableGen and allows emitting a full MLIR function for
pointwise add.

This "x.add" op is both type and rank-agnostic (by allowing ArrayRef of Expr
passed to For loops) and opens the door to spinning up a composable library of
existing and custom ops that should automate a lot of the tedious work in
TF/XLA -> MLIR.

Testing needs to be significantly improved but can be done in a separate CL.

PiperOrigin-RevId: 231982325
2019-03-29 16:05:23 -07:00
Nicolas Vasilache 35200435e7 Address cleanups from previous CL
This CL addresses some cleanups that were leftover after an incorrect rebase:
1. use StringSwitch
2. use // NOLINTNEXTLINE
3. remove a dead line of code

PiperOrigin-RevId: 231726640
2019-03-29 16:03:53 -07:00
Nicolas Vasilache 39d81f246a Introduce python bindings for MLIR EDSCs
This CL also introduces a set of python bindings using pybind11. The bindings
are exercised using a `test_py2andpy3.py` test suite that works for both
python 2 and 3.

`test_py3.py` on the other hand uses the more idiomatic,
python 3 only "PEP 3132 -- Extended Iterable Unpacking" to implement a rank
and type-agnostic copy with transposition.

Because python assignment is by reference, we cannot easily make the
assignment operator use the same type of sugaring as in C++; i.e. the
following:

```cpp
Stmt block = edsc::Block({
  For(ivs, zeros, shapeA, ones, {
    C[ivs] = IA[ivs] + IB[ivs]
})});
```

has no equivalent in the native Python EDSCs at this time.

However, the sugaring can be built as a simple DSL in python and is left as
future work.

PiperOrigin-RevId: 231337667
2019-03-29 15:59:14 -07:00
Nicolas Vasilache cacf05892e Add a C API for EDSCs in other languages + python
This CL adds support for calling EDSCs from other languages than C++.
Following the LLVM convention this CL:
1. declares simple opaque types and a C API in mlir-c/Core.h;
2. defines the implementation directly in lib/EDSC/Types.cpp and
lib/EDSC/MLIREmitter.cpp.

Unlike LLVM however the nomenclature for these types and API functions is not
well-defined, naming suggestions are most welcome.

To avoid the need for conversion functions, Types.h and MLIREmitter.h include
mlir-c/Core.h and provide constructors and conversion operators between the
mlir::edsc type and the corresponding C type.

In this first commit, mlir-c/Core.h only contains the types for the C API
to allow EDSCs to work from Python. This includes both a minimal set of core
MLIR
types (mlir_context_t, mlir_type_t, mlir_func_t) as well as the EDSC types
(edsc_mlir_emitter_t, edsc_expr_t, edsc_stmt_t, edsc_indexed_t). This can be
restructured in the future as concrete needs arise.

For now, the API only supports:
1. scalar types;
2. memrefs of scalar types with static or symbolic shapes;
3. functions with input and output of these types.

The C API is not complete wrt ownership semantics. This is in large part due
to the fact that python bindings are written with Pybind11 which allows very
idiomatic C++ bindings. An effort is made to write a large chunk of these
bindings using the C API but some C++isms are used where the design benefits
from this simplication. A fully isolated C API will make more sense once we
also integrate with another language like Swift and have enough use cases to
drive the design.

Lastly, this CL also fixes a bug in mlir::ExecutionEngine were the order of
declaration of llvmContext and the JIT result in an improper order of
destructors (which used to crash before the fix).

PiperOrigin-RevId: 231290250
2019-03-29 15:41:53 -07:00
Chris Lattner b42bea215a Change AffineApplyOp to produce a single result, simplifying the code that
works with it, and updating the g3docs.

PiperOrigin-RevId: 231120927
2019-03-29 15:40:38 -07:00
River Riddle 36babbd781 Change the ForInst induction variable to be a block argument of the body instead of the ForInst itself. This is a necessary step in converting ForInst into an operation.
PiperOrigin-RevId: 231064139
2019-03-29 15:40:23 -07:00
Nicolas Vasilache e4020c2d1a Add support for Return in EDSCs
This CL adds the Return op to EDSCs types and emitter.
This allows generating full function bodies that can be compiled all the way
down to LLVMIR and executed on CPU.

At this point, the MLIR lacks the testing infrastructure to exercise this.
End-to-end testing of full functions written in EDSCs is left for a future CL.

PiperOrigin-RevId: 230527530
2019-03-29 15:31:50 -07:00
Uday Bondhugula 7669204304 Improve / fix documentation for affine map composition utilities - NFC
- improve/fix doc comments for affine apply composition related methods.
- drop makeSingleValueComposedAffineApply - really redundant and out of line in
  a public API; it's just returning the first result of the composed affine
  apply op, and not making a single result affine map or an affine_apply op.

PiperOrigin-RevId: 230406169
2019-03-29 15:30:47 -07:00
Nicolas Vasilache 119af6712e Cleanup spurious printing bits in EDSCs
This CL also makes ScopedEDSCContexts to reset the Bindable numbering when
creating a new context.
This is useful to write minimal tests that don't use FileCheck pattern
captures for now.

PiperOrigin-RevId: 230079997
2019-03-29 15:28:13 -07:00
Nicolas Vasilache 9f3f39d61a Cleanup EDSCs
This CL performs a bunch of cleanups related to EDSCs that are generally
useful in the context of using them with a simple wrapping C API (not in this
CL) and with simple language bindings to Python and Swift.

PiperOrigin-RevId: 230066505
2019-03-29 15:27:58 -07:00
Nicolas Vasilache 4573a8da9a Fix improperly indexed DimOp in LowerVectorTransfers.cpp
This CL fixes a misunderstanding in how to build DimOp which triggered
execution issues in the CPU path.

The problem is that, given a `memref<?x4x?x8x?xf32>`, the expressions to
construct the dynamic dimensions should be:
`dim %arg, 0 : memref<?x4x?x8x?xf32>`
`dim %arg, 2 : memref<?x4x?x8x?xf32>`
and
`dim %arg, 4 : memref<?x4x?x8x?xf32>`

Before this CL, we wold construct:
`dim %arg, 0 : memref<?x4x?x8x?xf32>`
`dim %arg, 1 : memref<?x4x?x8x?xf32>`
`dim %arg, 2 : memref<?x4x?x8x?xf32>`

and expect the other dimensions to be constants.
This assumption seems consistent at first glance with the syntax of alloc:

```
    %tensor = alloc(%M, %N, %O) : memref<?x4x?x8x?xf32>
```

But this was actuallyincorrect.

This CL also makes the relevant functions available to EDSCs and removes
duplication of the incorrect function.

PiperOrigin-RevId: 229622766
2019-03-29 15:24:13 -07:00
Jacques Pienaar 4b2b5f5267 Enable specifying the op for which the reference implementation should be printed.
Allows emitting reference implementation of multiple ops inside the test lowering pass.

PiperOrigin-RevId: 229603494
2019-03-29 15:22:43 -07:00
Jacques Pienaar 9d4bb57189 Start a testing pass for EDSC lowering.
This is mostly plumbing to start allowing testing EDSC lowering. Prototype specifying reference implementation using verbose format without any generation/binding support. Add test pass that dumps the constructed EDSC (of which there can only be one). The idea is to enable iterating from multiple sides, this is wrong on many dimensions at the moment.

PiperOrigin-RevId: 229570535
2019-03-29 15:21:44 -07:00
Nicolas Vasilache 515ce1e68e Add edsc::Indexed helper struct to act as syntactic sugar
This CL adds edsc::Indexed.

This helper class exists purely for sugaring purposes and allows writing
expressions such as:

```mlir
   Indexed A(...), B(...), C(...);
   ForNest(ivs, zeros, shapeA, ones, {
     C[ivs] = A[ivs] + B[ivs]
   });
```

PiperOrigin-RevId: 229388644
2019-03-29 15:17:37 -07:00
Nicolas Vasilache 424041ad58 Add EDSC sugar
This allows load, store and ForNest to be used with both Expr and Bindable.
This simplifies writing generic pieces of MLIR snippet.

For instance, a generic pointwise add can now be written:

```cpp
// Different Bindable ivs, one per loop in the loop nest.
auto ivs = makeBindables(shapeA.size());
Bindable zero, one;
// Same bindable, all equal to `zero`.
SmallVector<Bindable, 8> zeros(ivs.size(), zero);
// Same bindable, all equal to `one`.
SmallVector<Bindable, 8> ones(ivs.size(), one);
// clang-format off
Bindable A, B, C;
Stmt scalarA, scalarB, tmp;
Stmt block = edsc::Block({
  ForNest(ivs, zeros, shapeA, ones, {
    scalarA = load(A, ivs),
    scalarB = load(B, ivs),
    tmp = scalarA + scalarB,
    store(tmp, C, ivs)
  }),
});
// clang-format on
```

This CL also adds some extra support for pretty printing that will be used in
a future CL when we introduce standalone testing of EDSCs. At the momen twe
are lacking the basic infrastructure to write such tests.

PiperOrigin-RevId: 229375850
2019-03-29 15:16:53 -07:00
Nicolas Vasilache 1b171e9357 Add EDSC support for operator*
PiperOrigin-RevId: 229097351
2019-03-29 15:12:55 -07:00
Nicolas Vasilache b941dc8238 [MLIR] Make MLIREmitter emit composed single-result AffineMap by construction
Arguably the dependence of EDSCs on Analysis is not great but on the other
hand this is a strict improvement in the emitted IR and since EDSCs are an
alternative to builders it makes sense that they have as much access to
Analysis as Transforms.

PiperOrigin-RevId: 228967624
2019-03-29 15:12:11 -07:00
Uday Bondhugula 56b3640b94 Misc readability and doc / code comment related improvements - NFC
- when SSAValue/MLValue existed, code at several places was forced to create additional
  aggregate temporaries of SmallVector<SSAValue/MLValue> to handle the conversion; get
  rid of such redundant code

- use filling ctors instead of explicit loops

- for smallvectors, change insert(list.end(), ...) -> append(...

- improve comments at various places

- turn getMemRefAccess into MemRefAccess ctor and drop duplicated
  getMemRefAccess. In the next CL, provide getAccess() accessors for load,
  store, DMA op's to return a MemRefAccess.

PiperOrigin-RevId: 228243638
2019-03-29 15:02:41 -07:00
Nicolas Vasilache 73f5c9c380 [MLIR] Sketch a simple set of EDSCs to declaratively write MLIR
This CL introduces a simple set of Embedded Domain-Specific Components (EDSCs)
in MLIR components:
1. a `Type` system of shell classes that closely matches the MLIR type system. These
types are subdivided into `Bindable` leaf expressions and non-bindable `Expr`
expressions;
2. an `MLIREmitter` class whose purpose is to:
  a. maintain a map of `Bindable` leaf expressions to concrete SSAValue*;
  b. provide helper functionality to specify bindings of `Bindable` classes to
     SSAValue* while verifying comformable types;
  c. traverse the `Expr` and emit the MLIR.

This is used on a concrete example to implement MemRef load/store with clipping in the
LowerVectorTransfer pass. More specifically, the following pseudo-C++ code:
```c++
MLFuncBuilder *b = ...;
Location location = ...;
Bindable zero, one, expr, size;
// EDSL expression
auto access = select(expr < zero, zero, select(expr < size, expr, size - one));
auto ssaValue = MLIREmitter(b)
    .bind(zero, ...)
    .bind(one, ...)
    .bind(expr, ...)
    .bind(size, ...)
    .emit(location, access);
```
is used to emit all the MLIR for a clipped MemRef access.

This simple EDSL can easily be extended to more powerful patterns and should
serve as the counterpart to pattern matchers (and could potentially be unified
once we get enough experience).

In the future, most of this code should be TableGen'd but for now it has
concrete valuable uses: make MLIR programmable in a declarative fashion.

This CL also adds Stmt, proper supporting free functions and rewrites
VectorTransferLowering fully using EDSCs.

The code for creating the EDSCs emitting a VectorTransferReadOp as loops
with clipped loads is:

```c++
  Stmt block = Block({
    tmpAlloc = alloc(tmpMemRefType),
    vectorView = vector_type_cast(tmpAlloc, vectorMemRefType),
    ForNest(ivs, lbs, ubs, steps, {
      scalarValue = load(scalarMemRef, accessInfo.clippedScalarAccessExprs),
      store(scalarValue, tmpAlloc, accessInfo.tmpAccessExprs),
    }),
    vectorValue = load(vectorView, zero),
    tmpDealloc = dealloc(tmpAlloc.getLHS())});
  emitter.emitStmt(block);
```

where `accessInfo.clippedScalarAccessExprs)` is created with:

```c++
select(i + ii < zero, zero, select(i + ii < N, i + ii, N - one));
```

The generated MLIR resembles:

```mlir
    %1 = dim %0, 0 : memref<?x?x?x?xf32>
    %2 = dim %0, 1 : memref<?x?x?x?xf32>
    %3 = dim %0, 2 : memref<?x?x?x?xf32>
    %4 = dim %0, 3 : memref<?x?x?x?xf32>
    %5 = alloc() : memref<5x4x3xf32>
    %6 = vector_type_cast %5 : memref<5x4x3xf32>, memref<1xvector<5x4x3xf32>>
    for %i4 = 0 to 3 {
      for %i5 = 0 to 4 {
        for %i6 = 0 to 5 {
          %7 = affine_apply #map0(%i0, %i4)
          %8 = cmpi "slt", %7, %c0 : index
          %9 = affine_apply #map0(%i0, %i4)
          %10 = cmpi "slt", %9, %1 : index
          %11 = affine_apply #map0(%i0, %i4)
          %12 = affine_apply #map1(%1, %c1)
          %13 = select %10, %11, %12 : index
          %14 = select %8, %c0, %13 : index
          %15 = affine_apply #map0(%i3, %i6)
          %16 = cmpi "slt", %15, %c0 : index
          %17 = affine_apply #map0(%i3, %i6)
          %18 = cmpi "slt", %17, %4 : index
          %19 = affine_apply #map0(%i3, %i6)
          %20 = affine_apply #map1(%4, %c1)
          %21 = select %18, %19, %20 : index
          %22 = select %16, %c0, %21 : index
          %23 = load %0[%14, %i1, %i2, %22] : memref<?x?x?x?xf32>
          store %23, %5[%i6, %i5, %i4] : memref<5x4x3xf32>
        }
      }
    }
    %24 = load %6[%c0] : memref<1xvector<5x4x3xf32>>
    dealloc %5 : memref<5x4x3xf32>
```

In particular notice that only 3 out of the 4-d accesses are clipped: this
corresponds indeed to the number of dimensions in the super-vector.

This CL also addresses the cleanups resulting from the review of the prevous
CL and performs some refactoring to simplify the abstraction.

PiperOrigin-RevId: 227367414
2019-03-29 14:50:23 -07:00