* Implement `FlatAffineConstraints::getConstantBound(EQ)`.
* Inject a simpler constraint for loops that have at most 1 iteration.
* Taking into account constant EQ bounds of FlatAffineConstraint dims/symbols during canonicalization of the resulting affine map in `canonicalizeMinMaxOp`.
Differential Revision: https://reviews.llvm.org/D114138
This patch extends the existing functionality of computing an explicit
representation for local variables, to also get the explicit representation,
instead of only the inequality pairs.
This is required for a future patch to remove redundant local ids based on
their explicit representation.
Reviewed By: arjunp
Differential Revision: https://reviews.llvm.org/D113814
This reverts commit bec488b818.
This commit introduced a layering violation between MLIR libraries.
Reverting for now while discussing on the original review thread.
This patch adds functionality to parse FlatAffineConstraints from a
StringRef with the intention to be used for unit tests. This should
make the construction of FlatAffineConstraints easier for testing
purposes.
The patch contains an example usage of the functionality in a unit test that
uses FlatAffineConstraints.
Reviewed By: bondhugula
Differential Revision: https://reviews.llvm.org/D113275
This patch factors out division representation computation from upper-lower bound
inequalities to a separate function. This is done to improve readability and reuse.
This patch is marked NFC since the only change is factoring out existing code
to a separate function.
Reviewed By: grosser
Differential Revision: https://reviews.llvm.org/D113463
This patch reorders mergeLocalIds usage to merge locals only after number of
dimensions and symbols are same. This does not change any functionality
because it does not matter in what order identifiers are merged, since
the reason to do it is to ensure that two FACs are aligned.
The order ensured in this patch simplifies a subsequent patch to improve
mergeLocalIds which requires dimensions and symbols to be aligned.
Reviewed By: bondhugula
Differential Revision: https://reviews.llvm.org/D112841
This patch fixes a bug in implementation `mergeSymbolIds` where symbol
identifiers were not unique after merging them. Asserts for checking uniqueness
before and after the merge are also added. The asserts checking uniqueness
after the merge fail without the fix on existing test cases.
Reviewed By: arjunp
Differential Revision: https://reviews.llvm.org/D111958
This patch removes code very specific to affine dependence analysis and
refactors it as a FlatAfffineRelation.
A FlatAffineRelation represents a set of ordered pairs (domain -> range) where
"domain" and "range" are tuples of identifiers. These relations are used to
represent an "access relation" for memory access on a memref. An access
relation maps elements of an iteration domain to the element(s) of an array
domain accessed by that iteration of the associated statement through some
array reference. The dependence relation representing the dependence
constraints between two memory accesses can be built by composing the access
relation of the destination access by the inverse of the access relation of
source access.
This patch does not change the functionality of the existing dependence
analysis in checkMemrefAccessDependence, but refactors it to use
FlatAffineRelations to deduplicate code and enable code reuse for future
development of features like scheduling, value-based dependence analysis, etc.
Reviewed By: bondhugula
Differential Revision: https://reviews.llvm.org/D110563
Precursor: https://reviews.llvm.org/D110200
Removed redundant ops from the standard dialect that were moved to the
`arith` or `math` dialects.
Renamed all instances of operations in the codebase and in tests.
Reviewed By: rriddle, jpienaar
Differential Revision: https://reviews.llvm.org/D110797
This revision adds a
```
FlatAffineValueConstraints(ValueRange ivs, ValueRange lbs, ValueRange ubs)
```
method and use it in hoist padding.
Differential Revision: https://reviews.llvm.org/D110427
This patch adds functionality to FlatAffineConstraints to remove local
variables using equalities. This helps in keeping output representation of
FlatAffineConstraints smaller.
This patch is part of a series of patches aimed at generalizing affine
dependence analysis.
Reviewed By: bondhugula
Differential Revision: https://reviews.llvm.org/D110056
Current warning message in method `addAffineForOpDomain` of mlir/lib/Analysis/AffineStructures.cpp is being printed to the stdout/stderr.
This patch redirects the warning with LLVM_DEBUG following standard llvm practice.
Reviewed By: bondhugula
Differential Revision: https://reviews.llvm.org/D108340
This patch adds mergeLocalIds andmergeSymbolIds as public functions
for FlatAffineConstraints and FlatAffineValueConstraints respectively.
mergeLocalIds is also required to support divisions in intersection,
subtraction, equality checks, and complement for PresburgerSet.
This patch is part of a series of patches aimed at generalizing affine
dependence analysis.
Reviewed By: bondhugula
Differential Revision: https://reviews.llvm.org/D110045
This patch refactors the existing implementation of computing an explicit
representation of an identifier as a floordiv in terms of other identifiers and
exposes this computation as a public function.
The computation of this representation is required to support local identifiers
in PresburgerSet subtract, complement and isEqual.
Reviewed By: bondhugula, arjunp
Differential Revision: https://reviews.llvm.org/D106662
* Add batched version of all `addId` variants, so that multiple IDs can be added at a time.
* Rename `addId` and variants to `insertId` and `appendId`. Most external users call `appendId`. Splitting `addId` into two functions also makes it possible to provide batched version for both. (Otherwise, the overloads are ambigious when calling `addId`.)
Differential Revision: https://reviews.llvm.org/D108532
Simplify affine.min ops, enabling various other canonicalizations inside the peeled loop body.
affine.min ops such as:
```
map = affine_map<(d0)[s0, s1] -> (s0, -d0 + s1)>
%r = affine.min #affine.min #map(%iv)[%step, %ub]
```
are rewritten them into (in the case the peeled loop):
```
%r = %step
```
To determine how an affine.min op should be rewritten and to prove its correctness, FlatAffineConstraints is utilized.
Differential Revision: https://reviews.llvm.org/D107222
* Rename ids to values in FlatAffineValueConstraints.
* Overall cleanup of comments in FlatAffineConstraints and FlatAffineValueConstraints.
Differential Revision: https://reviews.llvm.org/D107947
* Extract "value" functionality of `FlatAffineConstraints` into a new derived `FlatAffineValueConstraints` class. Current users of `FlatAffineConstraints` can use `FlatAffineValueConstraints` without additional code changes, thus NFC.
* `FlatAffineConstraints` no longer associates dimensions with SSA Values. All functionality that requires this, is moved to `FlatAffineValueConstraints`.
* `FlatAffineConstraints` no longer makes assumptions about where Values associated with dimensions are coming from.
Differential Revision: https://reviews.llvm.org/D107725
Reimplement this function in terms of `composeMatchingMap`.
Also fix a bug in `composeMatchingMap` where local dims of `this` could be missing in `localCst`.
Differential Revision: https://reviews.llvm.org/D107813
This function overload is similar to the existing `FlatAffineConstraints::addLowerOrUpperBound`. It constrains a dimension based on an affine map. However, in contrast to the other overloading, it does not attempt to align dimensions/symbols of the affine map with the dimensions/symbols of the constraint set. Instead, dimensions/symbols are expected to already be aligned.
Differential Revision: https://reviews.llvm.org/D107727
This function aligns an affine map (and operands) with given dims and syms SSA values.
This is useful in conjunction with `FlatAffineConstraints::addLowerOrUpperBound`, which requires the `boundMap` to be aligned with the constraint set's dims and syms.
Differential Revision: https://reviews.llvm.org/D107728
There are cases in which it is not desirable to fully compose the bound map with the operands when adding lower/upper bounds to a `FlatAffineConstraints`.
E.g., this is the case when bounds should be expressed in terms of the operands only (and not the operands' dependencies). This also makes `addLowerOrUpperBound` useable together with operands that are defined through semi-affine expressions.
Differential Revision: https://reviews.llvm.org/D107221
Bounds such as `dim_{pos} <= c_1 * dim_x + ...` where `x == pos` are invalid. `addLowerOrUpperBound` previously added an incorrect inequality to the set. Such cases are now explicitly rejected.
Differential Revision: https://reviews.llvm.org/D107220
This patch fixes a bug in the existing implementation of detectAsFloorDiv,
where floordivs with numerator with non-zero constant term and floordivs with
numerator only consisting of a constant term were not being detected.
Reviewed By: vinayaka-polymage
Differential Revision: https://reviews.llvm.org/D107214
Fix FlatAffineConstraints::getConstantBoundOnDimSize to ensure that
returned bounds on dim size are always non-negative regardless of the
constraints on that dimension. Add an assertion at the user.
Differential Revision: https://reviews.llvm.org/D105171
This results in significant deduplication of code. This patch is not expected to change any functionality, it's just some simplification in preparation for future work. Also slightly simplified some code that was being touched anyway and added some unit tests for some functions that were touched.
Reviewed By: bondhugula
Differential Revision: https://reviews.llvm.org/D105152
During slice computation of affine loop fusion, detect one id as the mod
of another id w.r.t a constant in a more generic way. Restrictions on
co-efficients of the ids is removed. Also, information from the
previously calculated ids is used for simplification of affine
expressions, e.g.,
If `id1` = `id2`,
`id_n - divisor * id_q - id_r + id1 - id2 = 0`, is simplified to:
`id_n - divisor * id_q - id_r = 0`.
If `c` is a non-zero integer,
`c*id_n - c*divisor * id_q - c*id_r = 0`, is simplified to:
`id_n - divisor * id_q - id_r = 0`.
Reviewed By: bondhugula, ayzhuang
Differential Revision: https://reviews.llvm.org/D104614
Fixes a bug in affine fusion pipeline where an incorrect slice is computed.
After the slice computation is done, original domain of the the source is
compared with the new domain that will result if the fusion succeeds. If the
new domain must be a subset of the original domain for the slice to be
valid. If the slice computed is incorrect, fusion based on such a slice is
avoided.
Relevant test cases are added/edited.
Fixes https://bugs.llvm.org/show_bug.cgi?id=49203
Differential Revision: https://reviews.llvm.org/D98239
This patch adds support for producer-consumer fusion scenarios with
multiple producer stores to the AffineLoopFusion pass. The patch
introduces some changes to the producer-consumer algorithm, including:
* For a given consumer loop, producer-consumer fusion iterates over its
producer candidates until a fixed point is reached.
* Producer candidates are gathered beforehand for each iteration of the
consumer loop and visited in reverse program order (not strictly guaranteed)
to maximize the number of loops fused per iteration.
In general, these changes were needed to simplify the multi-store producer
support and remove some of the workarounds that were introduced in the past
to support more fusion cases under the single-store producer limitation.
This patch also preserves the existing functionality of AffineLoopFusion with
one minor change in behavior. Producer-consumer fusion didn't fuse scenarios
with escaping memrefs and multiple outgoing edges (from a single store).
Multi-store producer scenarios will usually (always?) have multiple outgoing
edges so we couldn't fuse any with escaping memrefs, which would greatly limit
the applicability of this new feature. Therefore, the patch enables fusion for
these scenarios. Please, see modified tests for specific details.
Reviewed By: andydavis1, bondhugula
Differential Revision: https://reviews.llvm.org/D92876
With this, we have complete support for finding integer sample points in FlatAffineConstraints.
Reviewed By: ftynse
Differential Revision: https://reviews.llvm.org/D95047
This patch adds support for producer-consumer fusion scenarios with
multiple producer stores to the AffineLoopFusion pass. The patch
introduces some changes to the producer-consumer algorithm, including:
* For a given consumer loop, producer-consumer fusion iterates over its
producer candidates until a fixed point is reached.
* Producer candidates are gathered beforehand for each iteration of the
consumer loop and visited in reverse program order (not strictly guaranteed)
to maximize the number of loops fused per iteration.
In general, these changes were needed to simplify the multi-store producer
support and remove some of the workarounds that were introduced in the past
to support more fusion cases under the single-store producer limitation.
This patch also preserves the existing functionality of AffineLoopFusion with
one minor change in behavior. Producer-consumer fusion didn't fuse scenarios
with escaping memrefs and multiple outgoing edges (from a single store).
Multi-store producer scenarios will usually (always?) have multiple outgoing
edges so we couldn't fuse any with escaping memrefs, which would greatly limit
the applicability of this new feature. Therefore, the patch enables fusion for
these scenarios. Please, see modified tests for specific details.
Reviewed By: andydavis1, bondhugula
Differential Revision: https://reviews.llvm.org/D92876
With this, we have complete support for emptiness checks. This also paves the way for future support to check if two FlatAffineConstraints are equal.
Reviewed By: ftynse
Differential Revision: https://reviews.llvm.org/D94272
Subtraction is a foundational arithmetic operation that is often used when computing, for example, data transfer sets or cache hits. Since the result of subtraction need not be a convex polytope, a new class `PresburgerSet` is introduced to represent unions of convex polytopes.
Reviewed By: ftynse, bondhugula
Differential Revision: https://reviews.llvm.org/D87068
`swapId` used to be a static function in `AffineStructures.cpp`. This diff makes it accessible from the external world by turning it into a member function of `FlatAffineConstraints`. This will be very helpful for other projects that need to manipulate the content of `FlatAffineConstraints`.
Differential Revision: https://reviews.llvm.org/D87766
The prior diff that introduced `addAffineIfOpDomain` missed appending
constraints from the ifOp domain. This revision fixes this problem.
Differential Revision: https://reviews.llvm.org/D86421
This patch adds the capability to perform constraint redundancy checks for `FlatAffineConstraints` using `Simplex`, via a new member function `FlatAffineConstraints::removeRedundantConstraints`. The pre-existing redundancy detection algorithm runs a full rational emptiness check for each inequality separately for checking redundancy. Leveraging the existing `Simplex` infrastructure, in this patch we have an algorithm for redundancy checks that can check each constraint by performing pivots on the tableau, which provides an alternative to running Fourier-Motzkin elimination for each constraint separately.
Differential Revision: https://reviews.llvm.org/D84935
This diff attempts to resolve the TODO in `getOpIndexSet` (formerly
known as `getInstIndexSet`), which states "Add support to handle IfInsts
surronding `op`".
Major changes in this diff:
1. Overload `getIndexSet`. The overloaded version considers both
`AffineForOp` and `AffineIfOp`.
2. The `getInstIndexSet` is updated accordingly: its name is changed to
`getOpIndexSet` and its implementation is based on a new API `getIVs`
instead of `getLoopIVs`.
3. Add `addAffineIfOpDomain` to `FlatAffineConstraints`, which extracts
new constraints from the integer set of `AffineIfOp` and merges it to
the current constraint system.
4. Update how a `Value` is determined as dim or symbol for
`ValuePositionMap` in `buildDimAndSymbolPositionMaps`.
Differential Revision: https://reviews.llvm.org/D84698
Alexander Belyaev