This is done by changing Attribute to be a POD interface around an underlying pointer storage and adding in-class support for isa/dyn_cast/cast.
PiperOrigin-RevId: 218764173
- Introduce Fourier-Motzkin variable elimination to eliminate a dimension from
a system of linear equalities/inequalities. Update isEmpty to use this.
Since FM is only exact on rational/real spaces, an emptiness check based on
this is guaranteed to be exact whenever it says the underlying set is empty;
if it says, it's not empty, there may still be no integer points in it.
Also, supports a version that computes "dark shadows".
- Test this by checking for "always false" conditionals in if statements.
- Unique IntegerSet's that are small (few constraints, few variables). This
basically means the canonical empty set and other small sets that are
likely commonly used get uniqued; allows checking for the canonical empty set
by pointer. IntegerSet::kUniquingThreshold gives the threshold constraint size
for uniqui'ing.
- rename simplify-affine-expr -> simplify-affine-structures
Other cleanup
- IntegerSet::numConstraints, AffineMap::numResults are no longer needed;
remove them.
- add copy assignment operators for AffineMap, IntegerSet.
- rename Invalid() -> Null() on AffineExpr, AffineMap, IntegerSet
- Misc cleanup for FlatAffineConstraints API
PiperOrigin-RevId: 218690456
For some of the constant vector / tesor, if the compiler doesn't need to
interpret their elements content, they can be stored in this class to save the
serialize / deserialize cost.
syntax:
`opaque<` tensor-type `,` opaque-string `>`
opaque-string ::= `0x` [0-9a-fA-F]*
PiperOrigin-RevId: 218399426
a step forward because now every AbstractOperation knows which Dialect it is
associated with, enabling things in the future like "constant folding
hooks" which will be important for layering. This is also a bit nicer on
the registration side of things.
PiperOrigin-RevId: 218104230
We should be able to represent arbitrary precision Float-point values inside
the IR, so compiler optimizations, such as constant folding can be done
independently on the compiling platform.
This CL also added a new field, AttrValueGetter, to the Attr class definition
for TableGen. This field is used to customize which mlir::Attr getter method to
get the defined PrimitiveType.
PiperOrigin-RevId: 218034983
The SparseElementsAttr uses (COO) Coordinate List encoding to represents a
sparse tensor / vector. Specifically, the coordinates and values are stored as
two dense elements attributes. The first dense elements attribute is a 2-D
attribute with shape [N, ndims], which contains the indices of the elements
with nonzero values in the constant vector/tensor. The second elements
attribute is a 1-D attribute list with shape [N], which supplies the values for
each element in the first elements attribute. ndims is the rank of the
vector/tensor and N is the total nonzero elements.
The syntax is:
`sparse<` (tensor-type | vector-type)`, ` indices-attribute-list, values-attribute-list `>`
Example: a sparse tensor
sparse<vector<3x4xi32>, [[0, 0], [1, 2]], [1, 2]> represents the dense tensor
[[1, 0, 0, 0]
[0, 0, 2, 0]
[0, 0, 0, 0]]
PiperOrigin-RevId: 217764319
The syntax of dense vecor/tensor attribute value is
`dense<` (tensor-type | vector-type)`,` attribute-list`>`
and
attribute-list ::= `[` attribute-list (`, ` attribute-list)* `]`.
The construction of the dense vector/tensor attribute takes a vector/tensor
type and a character array as arguments. The size of the input array should be
larger than the size specified by the type argument. It also assumes the
elements of the vector or tensor have been trunked to the data type sizes in
the input character array, so it extends the trunked data to 64 bits when it is
retrieved.
PiperOrigin-RevId: 217762811
Associate BasicBlocks with the function being parsed to avoid leaks in the case of parse failures. Associating with the function means that we can no longer determine if defined/fwd declared simply by considering if a BasicBlock has an associated function, so track forward declared block references explicitly (this should also allow flagging multiple undeclared fwd references). Split out getting the named block from defining it, in the case of definition move the block to the end of the function.
Also destroy all forward reference placeholders in FunctionParser.
Return parse failure in parseAttributeDict if there is no left brace instead of
asserting.
PiperOrigin-RevId: 217049507
* Move Return, Constant and AffineApply out into BuiltinOps;
* BuiltinOps are always registered, while StandardOps follow the same dynamic registration;
* Kept isValidX in MLValue as we don't have a verify on AffineMap so need to keep it callable from Parser (I wanted to move it to be called in verify instead);
PiperOrigin-RevId: 216592527
This CL applies the same pattern as AffineMap to IntegerSet: a simple struct
that acts as the storage is allocated in the bump pointer. The IntegerSet is
immutable and accessed everywhere by value.
Note that unlike AffineMap, it is not possible to remove the MLIRContext
parameter when constructing an IntegerSet for now. One possible way to achieve
this would be to add an enum to distinguish between the mathematically empty
set, the universe set and other sets.
This is left for future discussion.
PiperOrigin-RevId: 216545361
This attribute represents a reference to a splat vector or tensor, where all
the elements have the same value. The syntax of the attribute is:
`splat<` (tensor-type | vector-type)`,` attribute-value `>`
PiperOrigin-RevId: 216537997
AbstractOperation* or an Identifier. This makes it possible to get to stuff in
AbstractOperation faster than going through a hash table lookup. This makes
constant folding a bit faster now, but will become more important with
subsequent changes.
PiperOrigin-RevId: 216476772
This CL applies the same pattern as AffineExpr to AffineMap: a simple struct
that acts as the storage is allocated in the bump pointer. The AffineMap is
immutable and accessed everywhere by value.
PiperOrigin-RevId: 216445930
This CL sketches what it takes for AffineExpr to fully have by-value semantics
and not be a not-so-smart pointer anymore.
This essentially makes the underyling class a simple storage struct and
implements the operations on the value type directly. Since there is no
forwarding of operations anymore, we can full isolate the storage class and
make a hard visibility barrier by moving detail::AffineExpr into
AffineExprDetail.h.
AffineExprDetail.h is only included where storage-related information is
needed.
PiperOrigin-RevId: 216385459
This CL:
1. performs the global codemod AffineXExpr->AffineXExprClass and
AffineXExprRef -> AffineXExpr;
2. simplifies function calls by removing the redundant MLIRContext parameter;
3. adds missing binary operator versions of scalar op AffineExpr where it
makes sense.
PiperOrigin-RevId: 216242674
This CL introduces a series of cleanups for AffineExpr value types:
1. to make it clear that the value types should be used, the pointer
AffineExpr types are put in the detail namespace. Unfortunately, since the
value type operator-> only forwards to the underlying pointer type, we
still
need to expose this in the include file for now;
2. AffineExprKind is ok to use, it thus comes out of detail and thus of
AffineExpr
3. getAffineDimExpr, getAffineSymbolExpr, getAffineConstantExpr are
similarly
extracted as free functions and their naming is mande consistent across
Builder, MLContext and AffineExpr
4. AffineBinaryOpEx::simplify functions are made into static free
functions.
In particular it is moved away from AffineMap.cpp where it does not belong
5. operator AffineExprType is made explicit
6. uses the binary operators everywhere possible
7. drops the pointer usage everywhere outside of AffineExpr.cpp,
MLIRContext.cpp and AsmPrinter.cpp
PiperOrigin-RevId: 216207212
This CL makes AffineExprRef into a value type.
Notably:
1. drops llvm isa, cast, dyn_cast on pointer type and uses member functions on
the value type. It may be possible to still use classof (in a followup CL)
2. AffineBaseExprRef aggressively casts constness away: if we mean the type is
immutable then let's jump in with both feet;
3. Drop implicit casts to the underlying pointer type because that always
results in surprising behavior and is not needed in practice once enough
cleanup has been applied.
The remaining negative I see is that we still need to mix operator. and
operator->. There is an ugly solution that forwards the methods but that ends
up duplicating the class hierarchy which I tried to avoid as much as
possible. But maybe it's not that bad anymore since AffineExpr.h would still
contain a single class hierarchy (the duplication would be impl detail in.cpp)
PiperOrigin-RevId: 216188003
1) affineint (as it is named) is not a type suitable for general computation (e.g. the multiply/adds in an integer matmul). It has undefined width and is undefined on overflow. They are used as the indices for forstmt because they are intended to be used as indexes inside the loop.
2) It can be used in both cfg and ml functions, and in cfg functions. As you mention, “symbols” are not affine, and we use affineint values for symbols.
3) Integers aren’t affine, the algorithms applied to them can be. :)
4) The only suitable use for affineint in MLIR is for indexes and dimension sizes (i.e. the bounds of those indexes).
PiperOrigin-RevId: 216057974
This CL starts by replacing AffineExpr* with value-type AffineExprRef in a few
places in the IR. By a domino effect that is pretty telling of the
inconsistencies in the codebase, const is removed where it makes sense.
The rationale is that the decision was concisously made that unique'd types
have pointer semantics without const specifier. This is fine but we should be
consistent. In the end, the only logical invariant is that there should never
be such a thing as a const AffineExpr*, const AffineMap* or const IntegerSet*
in our codebase.
This CL takes a number of shortcuts to killing const with fire, in particular
forcing const AffineExprRef to return the underlying non-const
AffineExpr*. This will be removed once AffineExpr* has disappeared in
containers but for now such shortcuts allow a bit of sanity in this long quest
for cleanups.
The **only** places where const AffineExpr*, const AffineMap* or const
IntegerSet* may still appear is by transitive needs from containers,
comparison operators etc.
There is still one major thing remaining here: figure out why cast/dyn_cast
return me a const AffineXXX*, which in turn requires a bunch of ugly
const_casts. I suspect this is due to the classof
taking const AffineXXXExpr*. I wonder whether this is a side effect of 1., if
it is coming from llvm itself (I'd doubt it) or something else (clattner@?)
In light of this, the whole discussion about const makes total sense to me now
and I would systematically apply the rule that in the end, we should never
have any const XXX in our codebase for unique'd types (assuming we can remove
them all in containers and no additional constness constraint is added on us
from the outside world).
PiperOrigin-RevId: 215811554
This CL uniformizes the uses of AffineExprWrap outside of IR.
The public API of AffineExpr builder is modified to only use AffineExprWrap.
A few places access AffineExprWrap.expr, this is only while the API is in
transition to easily keep track (i.e. make expr private and let the compiler
track the errors).
Parser.cpp exhibits patterns that are dependent on nullptr values so
converting it is left for another CL.
PiperOrigin-RevId: 215642005
Alternatively, we can defined a TFComplexType with a width parameter in the
mlir, then both types can be converted to the same mlir type with different width (like IntegerType).
We chose to use a direct mapping because there are only two TF Complex types.
PiperOrigin-RevId: 213856651
Use these methods to simplify existing code. Rename getConstantMap
getConstantAffineMap. Move declarations to group similar ones together.
PiperOrigin-RevId: 212814829
unroll/unroll-and-jam more powerful; add additional affine expr builder methods
- use previously added analysis/simplification to infer multiple of unroll
factor trip counts, making loop unroll/unroll-and-jam more general.
- for loop unroll, support bounds that are single result affine map's with the
same set of operands. For unknown loop bounds, loop unroll will now work as
long as trip count can be determined to be a multiple of unroll factor.
- extend getConstantTripCount to deal with single result affine map's with the
same operands. move it to mlir/Analysis/LoopAnalysis.cpp
- add additional builder utility methods for affine expr arithmetic
(difference, mod/floordiv/ceildiv w.r.t postitive constant). simplify code to
use the utility methods.
- move affine analysis routines to AffineAnalysis.cpp/.h from
AffineStructures.cpp/.h.
- Rename LoopUnrollJam to LoopUnrollAndJam to match class name.
- add an additional simplification for simplifyFloorDiv, simplifyCeilDiv
- Rename AffineMap::getNumOperands() getNumInputs: an affine map by itself does
not have operands. Operands are passed to it through affine_apply, from loop
bounds/if condition's, etc., operands are stored in the latter.
This should be sufficiently powerful for now as far as unroll/unroll-and-jam go for TPU
code generation, and can move to other analyses/transformations.
Loop nests like these are now unrolled without any cleanup loop being generated.
for %i = 1 to 100 {
// unroll factor 4: no cleanup loop will be generated.
for %j = (d0) -> (d0) (%i) to (d0) -> (5*d0 + 3) (%i) {
%x = "foo"(%j) : (affineint) -> i32
}
}
for %i = 1 to 100 {
// unroll factor 4: no cleanup loop will be generated.
for %j = (d0) -> (d0) (%i) to (d0) -> (d0 - d mod 4 - 1) (%i) {
%y = "foo"(%j) : (affineint) -> i32
}
}
for %i = 1 to 100 {
for %j = (d0) -> (d0) (%i) to (d0) -> (d0 + 128) (%i) {
%x = "foo"() : () -> i32
}
}
TODO(bondhugula): extend this to LoopUnrollAndJam as well in the next CL (with minor
changes).
PiperOrigin-RevId: 212661212
Previously the error could mislead into thinking it was a parser bug instead of the input being erroneous. Update to make it clearer.
PiperOrigin-RevId: 212271145
infrastructure, instead of returning a const char*. This allows custom
formatting and more interesting diagnostics.
This patch regresses the error message quality from the control flow
lowering pass, I'll address this in a subsequent patch.
PiperOrigin-RevId: 212210681
Ensure delimiters are absent where not expected. This is only checked in the case where operand count is known. This allows for the currently accepted case where there is a operand list with no delimiter and variable number of operands (which could be empty), followed by a delimited operand list.
PiperOrigin-RevId: 212202064
- Compress the identifier/kind of a Function into a single word.
- Eliminate otherFailure from verifier now that we always have a location
- Eliminate the error string from the verifier now that we always have
locations.
- Simplify the parser's handling of fn forward references, using the location
tracked by the function.
PiperOrigin-RevId: 211985101
- Add a new -verify mode to the mlir-opt tool that allows writing test cases
for optimization and other passes that produce diagnostics.
- Refactor existing the -check-parser-errors flag to mlir-opt into a new
-split-input-file option which is orthogonal to -verify.
- Eliminate the special error hook the parser maintained and use the standard
MLIRContext's one instead.
- Enhance the default MLIRContext error reporter to print file/line/col of
errors when it is available.
- Add new createChecked() methods to the builder that create ops and invoke
the verify hook on them, use this to detected unhandled code in the
RaiseControlFlow pass.
- Teach mlir-opt about expected-error @+, it previously only worked with @-
PiperOrigin-RevId: 211305770
This CL also includes two other minor changes:
- change the implemented syntax from 'if (cond)' to 'if cond', as specified by MLIR spec.
- a minor fix to the implementation of the ForStmt.
PiperOrigin-RevId: 210618122
(and more useful) way rather than hacking up a pile of attributes for it. In
the future this will grow to represent inlined locations, fusion cases etc, but
for now we start with simple Unknown and File/Line/Col locations. NFC.
PiperOrigin-RevId: 210485775
This commit creates a static constexpr limit for the IntegerType
bitwidth and uses it. The check had to be moved because Token is
not aware of IR/Type and it was a sign the abstraction leaked:
bitwidth limit is not a property of the Token but of the IntegerType.
Added a positive and a negative test at the limit.
PiperOrigin-RevId: 210388192
We seem to be using *& quite consistently across the codebase.
Replacing 2 occurences of **.
With this, `grep -R "\*\*" .` does not return instances of
accesses to state anymore.
PiperOrigin-RevId: 210385345
This revamps implementation of the loop bounds in the ForStmt, using general representation that supports operands. The frequent case of constant bounds is supported
via special access methods.
This also includes:
- Operand iterators for the Statement class.
- OpPointer::is() method to query the class of the Operation.
- Support for the bound shorthand notation parsing and printing.
- Validity checks for the bound operands used as dim ids and symbols
I didn't mean this CL to be so large. It just happened this way, as one thing led to another.
PiperOrigin-RevId: 210204858
parser hooks, as it has been subsumed by a simpler and cleaner mechanism.
Second, remove the "Inst" suffixes from a few methods in CFGFuncBuilder since
they are redundant and this is inconsistent with the other builders. NFC.
PiperOrigin-RevId: 210006263
operation and statement to have a location, and make it so a location is
required to be specified whenever you make one (though a null location is still
allowed). This is to encourage compiler authors to propagate loc info
properly, allowing our failability story to work well.
This is still a WIP - it isn't clear if we want to continue abusing Attribute
for location information, or whether we should introduce a new class heirarchy
to do so. This is good step along the way, and unblocks some of the tf/xla
work that builds upon it.
PiperOrigin-RevId: 210001406
OperationState contain a context and have the generic builder mechanics handle
the job of initializing the OperationState and setting the op name. NFC.
PiperOrigin-RevId: 209869948
River Riddle