Commit Graph

70 Commits

Author SHA1 Message Date
Uday Bondhugula
c9e121eb44 [MLIR] Enhance getLargestKnownDivisor for AffineExpr floordiv/ceildiv
The largest known divisor for expressions like (32 * d0 + 32, 128)
ceildiv 8 wasn't being computed tightly; a conservative value of 1 was
being returned. Address this. This leads to a broad improvement for
several affine analyses and rewrites that depend on knowing whether
something is a multiple of a specific constant or such largest known
constant.

Differential Revision: https://reviews.llvm.org/D140185
2022-12-17 12:45:38 +05:30
Arnab Dutta
b5626ae975 [MLIR] Fix bug in the method constructing semi affine expression from flattened form
Set proper offset to the second element of the index pair when either
lhs or rhs of a local expression is a dimensional identifier, so that
we do not have same index values for more than one local expression.

Reviewed By: springerm, hanchung

Differential Revision: https://reviews.llvm.org/D137389
2022-11-06 12:29:17 +05:30
Arnab Dutta
5e0d29103a [MLIR] Fix bug in the method constructing semi affine expression from flattened form
Set proper offset to the second element of the index pair, so that
we do not have same index values for more than one local expression.

Reviewed By: springerm

Differential Revision: https://reviews.llvm.org/D137062
2022-11-01 11:35:53 +05:30
Kazu Hirata
4a2377afd6 Use std::gcd (NFC)
To avoid changing semantics inadvertently, this patch casts arguments
to uint64_t before calling std::gcd.
2022-08-28 10:41:53 -07:00
Fangrui Song
fc63c0542c [mlir] LLVM_FALLTHROUGH => [[fallthrough]]. NFC 2022-08-08 20:56:05 -07:00
Dmitri Gribenko
aba43035bd Use llvm::sort instead of std::sort where possible
llvm::sort is beneficial even when we use the iterator-based overload,
since it can optionally shuffle the elements (to detect
non-determinism). However llvm::sort is not usable everywhere, for
example, in compiler-rt.

Reviewed By: nhaehnle

Differential Revision: https://reviews.llvm.org/D130406
2022-07-23 15:19:05 +02:00
Kazu Hirata
360c1111e3 Use llvm::is_contained (NFC) 2022-07-20 09:09:19 -07:00
Jeff Niu
b7f93c2809 [mlir] (NFC) run clang-format on all files 2022-07-14 13:32:13 -07:00
Kazu Hirata
6d5fc1e3d5 [mlir] Don't use Optional::getValue (NFC) 2022-06-20 23:20:25 -07:00
Mehdi Amini
e1f389a89f Apply clang-tidy fixes for readability-simplify-boolean-expr to MLIR (NFC) 2022-03-07 10:41:45 +00:00
Mehdi Amini
e4853be2f1 Apply clang-tidy fixes for performance-for-range-copy to MLIR (NFC) 2022-01-02 22:19:56 +00:00
Mehdi Amini
1fc096af1e Apply clang-tidy fixes for performance-unnecessary-value-param to MLIR (NFC)
Reviewed By: Mogball

Differential Revision: https://reviews.llvm.org/D116250
2022-01-02 01:45:18 +00:00
Arnab Dutta
ec7b0d4d34 [MLIR] Simplify Semi-affine expressions by rule based matching and replacing "expr - q * (expr floordiv q)" with "expr mod q" expression.
Add rule based matching for detecting and transforming "expr - q * (expr floordiv q)"
to "expr mod q", where q is a symbolic exxpression, in simplifyAdd function.

Reviewed By: bondhugula, dcaballe

Differential Revision: https://reviews.llvm.org/D112985
2021-11-20 21:05:36 +05:30
Arnab Dutta
1402299271 [MLIR] Simplify semi-affine expressions using flattening
For the semi affine expressions, whenever rhs of a floordiv, ceildiv, mod
or product expression is a symbolic expression, we introduce a local variable
representing the result, and store the floordiv/ceildiv, mod or product
affine expression in LocalExprs. In this way the expression is flattened,
and trivial addition and subtraction related simplifications are performed.
Also rule based matching for detecting and transforming "expr - q * (expr floordiv q)"
to "expr mod q", where q is a symbolic exxpression, in simplifyAdd function.

Differential Revision: https://reviews.llvm.org/D112808
2021-11-16 15:42:22 +05:30
Uday Bondhugula
41a8b46007 [MLIR] Fix AffineExpr getLargestKnownDivisor for ceildiv and floordiv
Fix AffineExpr `getLargestKnownDivisor` for ceil/floor div cases.
In these cases, nothing can be inferred on the divisor of the
result.

Add test case for `mod` as well.

Differential Revision: https://reviews.llvm.org/D112523
2021-10-26 16:21:29 +05:30
Krzysztof Drewniak
121aab84d1 [MLIR][Affine] Simplify nested modulo operations when able
It is the case that, for all positive a and b such that b divides a
(e mod (a * b)) mod b = e mod b. For example, ((d0 mod 35) mod 5) can
be simplified to (d0 mod 5), but ((d0 mod 35) mod 4) cannot be simplified
further (x = 36 is a counterexample).

This change enables more complex simplifications. For example,
((d0 * 72 + d1) mod 144) mod 9 can now simplify to (d0 * 72 + d1) mod 9
and thus to d1 mod 9. Expressions with chained modulus operators are
reasonably common in tensor applications, and this change _should_
improve code generation for such expressions.

Reviewed By: nicolasvasilache

Differential Revision: https://reviews.llvm.org/D109930
2021-09-17 19:06:00 +00:00
Matthias Springer
8e8b70aa84 [mlir][scf] Simplify affine.min ops after loop peeling
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
2021-08-19 17:24:53 +09:00
Nicolas Vasilache
5bc4f8846c s[mlir] Tighten computation of inferred SubView result type.
The AffineMap in the MemRef inferred by SubViewOp may have uncompressed symbols which result in type mismatch on otherwise unused symbols. Make the computation of the AffineMap compress those unused symbols which results in better canonical types.
Additionally, improve the error message to report which inferred type was expected.

Differential Revision: https://reviews.llvm.org/D96551
2021-02-11 22:38:16 +00:00
Nicolas Vasilache
93a873dfc9 [mlir][Affine] Revisit and simplify composeAffineMapAndOperands.
In prehistorical times, AffineApplyOp was allowed to produce multiple values.
This allowed the creation of intricate SSA use-def chains.
AffineApplyNormalizer was originally introduced as a means of reusing the AffineMap::compose method to write SSA use-def chains.
Unfortunately, symbols that were produced by an AffineApplyOp needed to be promoted to dims and reordered for the mathematical composition to be valid.

Since then, single result AffineApplyOp became the law of the land but the original assumptions were not revisited.

This revision revisits these assumptions and retires AffineApplyNormalizer.

Differential Revision: https://reviews.llvm.org/D94920
2021-01-19 13:52:07 +00:00
River Riddle
250f43d3ec [mlir] Remove the use of "kinds" from Attributes and Types
This greatly simplifies a large portion of the underlying infrastructure, allows for lookups of singleton classes to be much more efficient and always thread-safe(no locking). As a result of this, the dialect symbol registry has been removed as it is no longer necessary.

For users broken by this change, an alert was sent out(https://llvm.discourse.group/t/removing-kinds-from-attributes-and-types) that helps prevent a majority of the breakage surface area. All that should be necessary, if the advice in that alert was followed, is removing the kind passed to the ::get methods.

Differential Revision: https://reviews.llvm.org/D86121
2020-08-18 16:20:14 -07:00
River Riddle
86646be315 [mlir] Refactor StorageUniquer to require registration of possible storage types
This allows for bucketing the different possible storage types, with each bucket having its own allocator/mutex/instance map. This greatly reduces the amount of lock contention when multi-threading is enabled. On some non-trivial .mlir modules (>300K operations), this led to a compile time decrease of a single conversion pass by around half a second(>25%).

Differential Revision: https://reviews.llvm.org/D82596
2020-08-07 13:43:24 -07:00
Nicolas Vasilache
3110e7b077 [mlir] Introduce AffineMinSCF folding as a pattern
This revision adds a folding pattern to replace affine.min ops by the actual min value, when it can be determined statically from the strides and bounds of enclosing scf loop .

This matches the type of expressions that Linalg produces during tiling and simplifies boundary checks. For now Linalg depends both on Affine and SCF but they do not depend on each other, so the pattern is added there.
In the future this will move to a more appropriate place when it is determined.

The canonicalization of AffineMinOp operations in the context of enclosing scf.for and scf.parallel proceeds by:
  1. building an affine map where uses of the induction variable of a loop
  are replaced by `%lb + %step * floordiv(%iv - %lb, %step)` expressions.
  2. checking if any of the results of this affine map divides all the other
  results (in which case it is also guaranteed to be the min).
  3. replacing the AffineMinOp by the result of (2).

The algorithm is functional in simple parametric tiling cases by using semi-affine maps. However simplifications of such semi-affine maps are not yet available and the canonicalization does not succeed yet.

Differential Revision: https://reviews.llvm.org/D82009
2020-08-07 14:30:38 -04:00
Yash Jain
56593fa370 [MLIR] Simplify semi-affine expressions
Simplify semi-affine expression for the operations like ceildiv,
floordiv and modulo by any given symbol by checking divisibilty by that
symbol.

Some properties used in simplification are:

1) Commutative property of the floordiv and ceildiv:
((expr1 floordiv expr2) floordiv expr3 ) = ((expr1 floordiv expr3) floordiv expr2)
((expr1 ceildiv expr2) ceildiv expr3 ) = ((expr1 ceildiv expr3) ceildiv expr2)

While simplification if operations are different no simplification is
possible as there is no property that simplify expressions like these:
((expr1 ceildiv expr2) floordiv expr3) or  ((expr1 floordiv expr2)
ceildiv expr3).

2) If both expr1 and expr2 are divisible by the expr3 then:
(expr1 % expr2) / expr3 = ((expr1 / expr3) % (expr2 / expr3))
where / is divide symbol.

3) If expr1 is divisible by expr2 then expr1 % expr2 = 0.

Signed-off-by: Yash Jain <yash.jain@polymagelabs.com>

Differential Revision: https://reviews.llvm.org/D84920
2020-08-04 22:07:18 +05:30
Jakub Lichman
f9c8febc52 [mlir] Added support for symbols inside linalg.generic and map concatenation
This commit adds functionality needed for implementation of convolutions with
linalg.generic op. Since linalg.generic right now expects indexing maps to be
just permutations, offset indexing needed in convolutions is not possible.
Therefore in this commit we address the issue by adding support for symbols inside
indexing maps which enables more advanced indexing. The upcoming commit will
solve the problem of computing loop bounds from such maps.

Differential Revision: https://reviews.llvm.org/D83158
2020-07-20 19:20:47 +02:00
River Riddle
9db53a1827 [mlir][NFC] Remove usernames and google bug numbers from TODO comments.
These were largely leftover from when MLIR was a google project, and don't really follow LLVM guidelines.
2020-07-07 01:40:52 -07:00
River Riddle
92f1562f3d [mlir][NFC] Remove the STLExtras.h header file now that it has been merged into LLVM.
Now that no more utilities exist within, this file can be deleted.

Differential Revision: https://reviews.llvm.org/D78079
2020-04-14 15:14:41 -07:00
Nicolas Vasilache
882ba48474 [mlir][Linalg] Create a tool to generate named Linalg ops from a Tensor Comprehensions-like specification.
Summary:

This revision adds a tool that generates the ODS and C++ implementation for "named" Linalg ops according to the [RFC discussion](https://llvm.discourse.group/t/rfc-declarative-named-ops-in-the-linalg-dialect/745).

While the mechanisms and language aspects are by no means set in stone, this revision allows connecting the pieces end-to-end from a mathematical-like specification.

Some implementation details and short-term decisions taken for the purpose of bootstrapping and that are not set in stone include:

    1. using a "[Tensor Comprehension](https://arxiv.org/abs/1802.04730)-inspired" syntax
    2. implicit and eager discovery of dims and symbols when parsing
    3. using EDSC ops to specify the computation (e.g. std_addf, std_mul_f, ...)

A followup revision will connect this tool to tablegen mechanisms and allow the emission of named Linalg ops that automatically lower to various loop forms and run end to end.

For the following "Tensor Comprehension-inspired" string:

```
    def batch_matmul(A: f32(Batch, M, K), B: f32(K, N)) -> (C: f32(Batch, M, N)) {
      C(b, m, n) = std_addf<k>(std_mulf(A(b, m, k), B(k, n)));
    }
```

With -gen-ods-decl=1, this emits (modulo formatting):

```
      def batch_matmulOp : LinalgNamedStructured_Op<"batch_matmul", [
        NInputs<2>,
        NOutputs<1>,
        NamedStructuredOpTraits]> {
          let arguments = (ins Variadic<LinalgOperand>:$views);
          let results = (outs Variadic<AnyRankedTensor>:$output_tensors);
          let extraClassDeclaration = [{
            llvm::Optional<SmallVector<StringRef, 8>> referenceIterators();
            llvm::Optional<SmallVector<AffineMap, 8>> referenceIndexingMaps();
            void regionBuilder(ArrayRef<BlockArgument> args);
          }];
          let hasFolder = 1;
      }
```

With -gen-ods-impl, this emits (modulo formatting):

```
      llvm::Optional<SmallVector<StringRef, 8>> batch_matmul::referenceIterators() {
          return SmallVector<StringRef, 8>{ getParallelIteratorTypeName(),
                                            getParallelIteratorTypeName(),
                                            getParallelIteratorTypeName(),
                                            getReductionIteratorTypeName() };
      }
      llvm::Optional<SmallVector<AffineMap, 8>> batch_matmul::referenceIndexingMaps()
      {
        MLIRContext *context = getContext();
        AffineExpr d0, d1, d2, d3;
        bindDims(context, d0, d1, d2, d3);
        return SmallVector<AffineMap, 8>{
            AffineMap::get(4, 0, {d0, d1, d3}),
            AffineMap::get(4, 0, {d3, d2}),
            AffineMap::get(4, 0, {d0, d1, d2}) };
      }
      void batch_matmul::regionBuilder(ArrayRef<BlockArgument> args) {
        using namespace edsc;
        using namespace intrinsics;
        ValueHandle _0(args[0]), _1(args[1]), _2(args[2]);

        ValueHandle _4 = std_mulf(_0, _1);
        ValueHandle _5 = std_addf(_2, _4);
        (linalg_yield(ValueRange{ _5 }));
      }
```

Differential Revision: https://reviews.llvm.org/D77067
2020-04-10 13:59:25 -04:00
Uday Bondhugula
332f0b3cd4 Affine expr simplification for add of const multiple of same expression
- Detect "c_1 * expr + c_2 * expr" as (c_1 + c_2) * expr
- subsumes things like 'expr - expr' and "expr * -1 + expr" as 0.
- change AffineConstantExpr ctor to allow default null init

Signed-off-by: Uday Bondhugula <uday@polymagelabs.com>

Differential Revision: https://reviews.llvm.org/D76233
2020-03-17 08:22:17 +05:30
Uday Bondhugula
91153e0624 [mlir][NFC] remove stray decl of toAffineExpr, rename for readability
Summary:
- remove stray toAffineExpr decl in affine analysis (name duplicate of
  mlir::toAffineExpr)

- rename mlir::toAffineExpr for better readability

- related NFC changes

Signed-off-by: Uday Bondhugula <uday@polymagelabs.com>

Differential Revision: https://reviews.llvm.org/D75694
2020-03-06 22:38:47 -08:00
Frank Laub
c4119a5b90 [MLIR][Affine][NFC] Remove obsolete and ambiguous definitions
Summary:
Looks like a refactor that was never completed.

This change removes some unused and ambiguous definitions.

Reviewed By: bondhugula, nicolasvasilache, rriddle

Differential Revision: https://reviews.llvm.org/D75586
2020-03-04 13:14:25 -08:00
Mehdi Amini
308571074c Mass update the MLIR license header to mention "Part of the LLVM project"
This is an artifact from merging MLIR into LLVM, the file headers are
now aligned with the rest of the project.
2020-01-26 03:58:30 +00:00
Mehdi Amini
56222a0694 Adjust License.txt file to use the LLVM license
PiperOrigin-RevId: 286906740
2019-12-23 15:33:37 -08:00
River Riddle
4562e389a4 NFC: Remove unnecessary 'llvm::' prefix from uses of llvm symbols declared in mlir namespace.
Aside from being cleaner, this also makes the codebase more consistent.

PiperOrigin-RevId: 286206974
2019-12-18 09:29:20 -08:00
Uday Bondhugula
36a415bcc5 More affine expr simplifications for floordiv and mod
Add one more simplification for floordiv and mod affine expressions.
Examples:
 (2*d0 + 1) floordiv 2 is simplified to d0
 (8*d0 + 4*d1 + d2) floordiv 4 simplified to 4*d0 + d1 + d2 floordiv 4.
 etc.

 Similarly, (4*d1 + 1) mod 2 is simplified to 1,
            (2*d0 + 8*d1) mod 8 simplified to 2*d0 mod 8.

Change getLargestKnownDivisor to return int64_t to be consistent and
to avoid casting at call sites (since the return value is used in expressions
of int64_t/index type).

Signed-off-by: Uday Bondhugula <uday@polymagelabs.com>

Closes tensorflow/mlir#202

COPYBARA_INTEGRATE_REVIEW=https://github.com/tensorflow/mlir/pull/202 from bondhugula:affine b13fcb2f1c00a39ca5434613a02408e085a80e77
PiperOrigin-RevId: 284866710
2019-12-10 16:00:53 -08:00
Uday Bondhugula
f559c38c28 Upgrade/fix/simplify store to load forwarding
- fix store to load forwarding for a certain set of cases (where
  forwarding shouldn't have happened); use AffineValueMap difference
  based MemRefAccess equality checking; utility logic is also greatly
  simplified

- add missing equality/inequality operators for AffineExpr ==/!= ints

- add == != operators on MemRefAccess

Closes tensorflow/mlir#136

COPYBARA_INTEGRATE_REVIEW=https://github.com/tensorflow/mlir/pull/136 from bondhugula:store-load-forwarding d79fd1add8bcfbd9fa71d841a6a9905340dcd792
PiperOrigin-RevId: 270457011
2019-09-21 10:08:56 -07:00
Uday Bondhugula
07ecb011a7 Fix AffineExpr::simplifyAdd bug
- fix missing check while simplifying an expression with floordiv to a
  mod
- fixes issue tensorflow/mlir#82

Signed-off-by: Uday Bondhugula <uday@polymagelabs.com>

Closes tensorflow/mlir#84

PiperOrigin-RevId: 264338353
2019-08-20 01:53:07 -07:00
Jacques Pienaar
772930f8c6 Update style/clang-format (NFC).
Update to be consistent & so that future save + clang-format workflows don't introduce extra changes.

PiperOrigin-RevId: 259361174
2019-07-22 11:29:21 -07:00
Nicolas Vasilache
28fb743798 More general subview calculation in tiling
This CL refactors tiling to enable tiling of views that are not just specified by a simple permutation. This allows the tiling of convolutions for which a new example is added.

PiperOrigin-RevId: 256346028
2019-07-03 14:36:42 -07:00
Alex Zinenko
c74996d199 AffineExpr: factor uniqu'ing out of MLIRContext.cpp
Affine expressions are designed as components of an attribute and are unique'd
    in the MLIRContext.  When affine expressions were implemented, uniqu'ing
    objects in a context required to modify MLIRContext implementation.  This is no
    longer the case as generic StorageUniquer has been introduced.  Port the
    AffineExpr construction to use the new infrastructure by introducing an
    affineUniquer into the MLIRContext.

--

PiperOrigin-RevId: 249207539
2019-06-01 19:53:43 -07:00
Mehdi Amini
ff5d021c39 Add llvm_unreachable in unreachable path to silence GCC warning (NFC)
The switch is supposed to be fully covered, but GCC warns that:
     "control reaches end of non-void function"

--

PiperOrigin-RevId: 247672430
2019-05-10 19:30:06 -07:00
Uday Bondhugula
b269481106 Cleanup post cl/235283610 - NFC
- remove stale comments + cleanup
- drop MLIRContext * field from expr flattener

PiperOrigin-RevId: 235621178
2019-03-29 16:42:20 -07:00
Uday Bondhugula
dfe07b7bf6 Refactor AffineExprFlattener and move FlatAffineConstraints out of IR into
Analysis - NFC

- refactor AffineExprFlattener (-> SimpleAffineExprFlattener) so that it
  doesn't depend on FlatAffineConstraints, and so that FlatAffineConstraints
  could be moved out of IR/; the simplification that the IR needs for
  AffineExpr's doesn't depend on FlatAffineConstraints
- have AffineExprFlattener derive from SimpleAffineExprFlattener to use for
  all Analysis/Transforms purposes; override addLocalFloorDivId in the derived
  class

- turn addAffineForOpDomain into a method on FlatAffineConstraints
- turn AffineForOp::getAsValueMap into an AffineValueMap ctor

PiperOrigin-RevId: 235283610
2019-03-29 16:39:32 -07:00
Uday Bondhugula
a1dad3a5d9 Extend/improve getSliceBounds() / complete TODO + update unionBoundingBox
- compute slices precisely where the destination iteration depends on multiple source
  iterations (instead of over-approximating to the whole source loop extent)
- update unionBoundingBox to deal with input with non-matching symbols
- reenable disabled backend test case

PiperOrigin-RevId: 234714069
2019-03-29 16:33:11 -07:00
River Riddle
10237de8eb Refactor the affine analysis by moving some functionality to IR and some to AffineOps. This is important for allowing the affine dialect to define canonicalizations directly on the operations instead of relying on transformation passes, e.g. ComposeAffineMaps. A summary of the refactoring:
* AffineStructures has moved to IR.

* simplifyAffineExpr/simplifyAffineMap/getFlattenedAffineExpr have moved to IR.

* makeComposedAffineApply/fullyComposeAffineMapAndOperands have moved to AffineOps.

* ComposeAffineMaps is replaced by AffineApplyOp::canonicalize and deleted.

PiperOrigin-RevId: 232586468
2019-03-29 16:15:41 -07:00
Nicolas Vasilache
c449e46ceb Introduce AffineExpr::compose(AffineMap)
This CL is the 1st on the path to simplifying AffineMap composition.
This CL uses the now accepted AffineExpr.replaceDimsAndSymbols to
implement `AffineExpr::compose(AffineMap)`.

Arguably, `simplifyAffineExpr` should be part of IR and not Analysis but
this CL does not yet pull the trigger on that.

PiperOrigin-RevId: 228265845
2019-03-29 15:03:36 -07:00
Uday Bondhugula
94c2d969ce Rename getAffineBinaryExpr -> getAffineBinaryOpExpr, getBinaryAffineOpExpr ->
getAffineBinaryOpExpr for consistency (NFC)

- this is consistent with the name of the class and getAffineDimExpr/ConstantExpr, etc.

PiperOrigin-RevId: 228164959
2019-03-29 14:59:52 -07:00
Nicolas Vasilache
28cf580555 Cleanup spurious DenseMap include
PiperOrigin-RevId: 228059305
2019-03-29 14:58:38 -07:00
Nicolas Vasilache
618c6a74c6 [MLIR] Introduce normalized single-result unbounded AffineApplyOp
Supervectorization does not plan on handling multi-result AffineMaps and
non-canonical chains of > 1 AffineApplyOp.
This CL introduces a simpler abstraction and composition of single-result
unbounded AffineApplyOp by using the existing unbound AffineMap composition.

This CL adds a simple API call and relevant tests:

```c++
OpPointer<AffineApplyOp> makeNormalizedAffineApply(
  FuncBuilder *b, Location loc, AffineMap map, ArrayRef<Value*> operands);
```

which creates a single-result unbounded AffineApplyOp.
The operands of AffineApplyOp are not themselves results of AffineApplyOp by
consrtuction.

This represent the simplest possible interface to complement the composition
of (mathematical) AffineMap, for the cases when we are interested in applying
it to Value*.

In this CL the composed AffineMap is not compressed (i.e. there exist operands
that are not part of the result). A followup commit will compress to normal
form.

The single-result unbounded AffineApplyOp abstraction will be used in a
followup CL to support the MaterializeVectors pass.

PiperOrigin-RevId: 227879021
2019-03-29 14:56:37 -07:00
Chris Lattner
7983bbc251 Introduce a simple canonicalization of affine_apply that drops unused dims and
symbols.

Included with this is some other infra:
 - Testcases for other canonicalizations that I will implement next.
 - Some helpers in AffineMap/Expr for doing simple walks without defining whole
   visitor classes.
 - A 'replaceDimsAndSymbols' facility that I'll be using to simplify maps and
   exprs, e.g. to fold one constant into a mapping and to drop/renumber unused dims.
 - Allow index (and everything else) to work in memref's, as we previously
   discussed, to make the testcase easier to write.
 - A "getAffineBinaryExpr" helper to produce a binop when you know the kind as
   an enum.

This line of work will eventually subsume the ComposeAffineApply pass, but it is no where close to that yet :-)

PiperOrigin-RevId: 227852951
2019-03-29 14:56:07 -07:00
Nicolas Vasilache
4adc169bd0 [MLIR] Add AffineMap composition and use it in Materialization
This CL adds the following free functions:
```
/// Returns the AffineExpr e o m.
AffineExpr compose(AffineExpr e, AffineMap m);
/// Returns the AffineExpr f o g.
AffineMap compose(AffineMap f, AffineMap g);
```

This addresses the issue that AffineMap composition is only available at a
distance via AffineValueMap and is thus unusable on Attributes.
This CL thus implements AffineMap composition in a more modular and composable
way.

This CL does not claim that it can be a good replacement for the
implementation in AffineValueMap, in particular it does not support bounded
maps atm.

Standalone tests are added that replicate some of the logic of the AffineMap
composition pass.

Lastly, affine map composition is used properly inside MaterializeVectors and
a standalone test is added that requires permutation_map composition with a
projection map.

PiperOrigin-RevId: 224376870
2019-03-29 14:20:22 -07:00