Commit Graph

89 Commits

Author SHA1 Message Date
Lukas Sommer d86ece13d9 Keep output file after successful execution of mlir-opt
Invoke `keep()` on the output file of `mlir-opt` in case the invocation of `MlirOptMain` was successful, to make sure the output file is not deleted on exit from `mlir-opt`.
Fixes a similar problem in `standalone-opt` from the example for an out-of-tree, standalone MLIR dialect.

This revision also adds a missing parameter to the invocation of `MlirOptMain` in `standalone-opt`.

Differential Revision: https://reviews.llvm.org/D77643
2020-04-08 03:37:45 +00:00
Mehdi Amini bab5bcf8fd Add a flag on the context to protect against creation of operations in unregistered dialects
Differential Revision: https://reviews.llvm.org/D76903
2020-03-30 19:37:31 +00:00
Uday Bondhugula f273e5c507 [MLIR] Fix permuteLoops utility
Rewrite mlir::permuteLoops (affine loop permutation utility) to fix
incorrect approach. Avoiding using sinkLoops entirely - use single move
approach. Add test pass.

This fixes https://bugs.llvm.org/show_bug.cgi?id=45328

Depends on D77003.

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

Differential Revision: https://reviews.llvm.org/D77004
2020-03-30 23:38:23 +05:30
Marcel Koester 86bbbb317b [mlir] Extended Dominance analysis with a function to find the nearest common dominator of two given blocks.
The Dominance analysis currently misses a utility function to find the nearest common dominator of two given blocks. This is required for a huge variety of different control-flow analyses and transformations. This commit adds this function and moves the getNode function from DominanceInfo to DominanceInfoBase, as it also works for post dominators.

Differential Revision: https://reviews.llvm.org/D75507
2020-03-27 14:55:40 +01:00
River Riddle e8f5c072f6 [mlir] Move the testing pass for GpuKernelToCubin to the test/ directory
Summary:
This removes the static pass registration, and also cleans up some lingering technical debt.

Differential Revision: https://reviews.llvm.org/D76554
2020-03-22 03:38:09 -07:00
River Riddle e74961eee2 [mlir][NFC] Remove Analysis/Passes.h
Summary:
This file only contains references to test passes, and was never removed when the test passes were moved to the test/ directory.

Differential Revision: https://reviews.llvm.org/D76553
2020-03-22 03:16:51 -07:00
River Riddle f8923584da [mlir][SideEffects] Define a set of interfaces and traits for defining side effects
This revision introduces the infrastructure for defining side-effects and attaching them to operations. This infrastructure allows for defining different types of side effects, that don't interact with each other, but use the same internal mechanisms. At the base of this is an interface that allows operations to specify the different effect instances that are exhibited by a specific operation instance. An effect instance is comprised of the following:

* Effect: The specific effect being applied.
  For memory related effects this may be reading from memory, storing to memory, etc.

* Value: A specific value, either operand/result/region argument, the effect pertains to.

* Resource: This is a global entity that represents the domain within which the effect is being applied.

MLIR serves many different abstractions, which cover many different domains. Simple effects are may have very different context, for example writing to an in-memory buffer vs a database. This revision defines uses this infrastructure to define a set of initial MemoryEffects. The are effects that generally correspond to memory of some kind; Allocate, Free, Read, Write.

This set of memory effects will be used in follow revisions to generalize various parts of the compiler, and make others more powerful(e.g. DCE).

This infrastructure was originally proposed here:
https://groups.google.com/a/tensorflow.org/g/mlir/c/v2mNl4vFCUM

Differential Revision: https://reviews.llvm.org/D74439
2020-03-06 14:04:36 -08:00
Stephen Neuendorffer 01b209679f [MLIR] add show-dialects option for mlir-opt
Display the list of dialects known to mlir-opt.  This is useful
for ensuring that linkage has happened correctly, for instance.

Differential Revision: https://reviews.llvm.org/D74865
2020-02-27 10:43:39 -08:00
Stephan Herhut 7a7eacc797 [MLIR][GPU] Implement a simple greedy loop mapper.
Summary:
The mapper assigns annotations to loop.parallel operations that
are compatible with the loop to gpu mapping pass. The outermost
loop uses the grid dimensions, followed by block dimensions. All
remaining loops are mapped to sequential loops.

Differential Revision: https://reviews.llvm.org/D74963
2020-02-25 11:42:42 +01:00
Lei Zhang 8358ddbe5d [mlir][spirv] NFC: Move test passes to test/lib
Previously C++ test passes for SPIR-V were put under
test/Dialect/SPIRV. Move them to test/lib/Dialect/SPIRV
to create a better structure.

Also fixed one of the test pass to use new
PassRegistration mechanism.

Differential Revision: https://reviews.llvm.org/D75066
2020-02-24 14:17:02 -05:00
Diego Caballero d7058acc14 [mlir] Add MemRef filter to affine data copy optimization
This patch extends affine data copy optimization utility with an
optional memref filter argument. When the memref filter is used, data
copy optimization will only generate copies for such a memref.

Note: this patch is just porting the memref filter feature from Uday's
'hop' branch: https://github.com/bondhugula/llvm-project/tree/hop.

Reviewed By: bondhugula

Differential Revision: https://reviews.llvm.org/D74342
2020-02-14 13:41:45 -08:00
Mehdi Amini c64770506b Remove static registration for dialects, and the "alwayslink" hack for passes
In the previous state, we were relying on forcing the linker to include
all libraries in the final binary and the global initializer to self-register
every piece of the system. This change help moving away from this model, and
allow users to compose pieces more freely. The current change is only "fixing"
the dialect registration and avoiding relying on "whole link" for the passes.
The translation is still relying on the global registry, and some refactoring
is needed to make this all more convenient.

Differential Revision: https://reviews.llvm.org/D74461
2020-02-12 09:13:02 +00:00
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 9274ed66ef Refactor pass pipeline command line parsing to support explicit pipeline strings.
This allows for explicitly specifying the pipeline to add to the pass manager. This includes the nesting structure, as well as the passes/pipelines to run. A textual pipeline string is defined as a series of names, each of which may in itself recursively contain a nested pipeline description. A name is either the name of a registered pass, or pass pipeline, (e.g. "cse") or the name of an operation type (e.g. "func").

For example, the following pipeline:
$ mlir-opt foo.mlir -cse -canonicalize -lower-to-llvm

Could now be specified as:
$ mlir-opt foo.mlir -pass-pipeline='func(cse, canonicalize), lower-to-llvm'

This will allow for running pipelines on nested operations, like say spirv modules. This does not remove any of the current functionality, and in fact can be used in unison. The new option is available via 'pass-pipeline'.

PiperOrigin-RevId: 268954279
2019-09-13 12:10:31 -07:00
Jacques Pienaar 33a8642f53 InitLLVM already initializes PrettyStackTraceProgram
Remove extra PrettyStackTraceProgram and use InitLLVM consistently.

PiperOrigin-RevId: 264041205
2019-08-18 11:32:52 -07:00
Jacques Pienaar 257a654b72 Split out mlir-opt main into separate file.
Enable reusing the real mlir-opt main from unit tests and in case where
additional initialization needs to happen before main is invoked (e.g., when
using different command line flag libraries).

PiperOrigin-RevId: 254764575
2019-06-24 13:45:39 -07:00
Geoffrey Martin-Noble d7d69569e7 Rename -verify mlir-opt flag to -verify-expected-diagnostics
This name has caused some confusion because it suggests that it's running op verification (and that this verification isn't getting run by default).

PiperOrigin-RevId: 254035268
2019-06-19 23:08:03 -07:00
River Riddle 58e40178fc Remove the newline from the mlir-opt 'split-input-file' flag marker. This fixes support for DOS style new lines(/r/n).
--

PiperOrigin-RevId: 250899420
2019-06-01 20:12:11 -07:00
River Riddle 5fd4ec1b78 Move the diagnostic verification functionality out of mlir-opt and into a new llvm::SourceMgr diagnostic handler 'SourceMgrDiagnosticVerifierHandler'. This will allow for other tools to reuse the 'expected-*' functionality.
--

PiperOrigin-RevId: 247514684
2019-05-10 19:26:51 -07:00
River Riddle 4bc23a40f4 Add a utility diagnostic handler class, SourceMgrDiagnosticHandler, to interface with llvm::SourceMgr. This lowers the barrier of entry for tools to get rich diagnostic handling when using llvm::SourceMgr.
--

PiperOrigin-RevId: 247358610
2019-05-10 19:24:54 -07:00
River Riddle b14c4b4ca8 Add support for basic remark diagnostics. This is the minimal functionality needed to separate notes from remarks. It also provides a starting point to start building out better remark infrastructure.
--

PiperOrigin-RevId: 246175216
2019-05-06 08:24:02 -07:00
River Riddle eaf7f6b671 Start sketching out a new diagnostics infrastructure. Create a new class 'DiagnosticEngine' and move the diagnostic handler support and final diagnostic emission from the MLIRContext to it.
--

PiperOrigin-RevId: 246163897
2019-05-06 08:23:53 -07:00
Jacques Pienaar 1156b2df35 Cleanups for OSS build.
PiperOrigin-RevId: 238999629
2019-03-29 17:23:23 -07:00
River Riddle 6810c8bdc1 Moving the IR printing and execution timing options out of mlir-opt and into lib/Pass. We now expose two methods: registerPassManagerCLOptions and applyPassManagerCLOptions; to allow for multiple different users (mlir-opt, etc.) to opt-in to this common functionality.
PiperOrigin-RevId: 238836911
2019-03-29 17:21:50 -07:00
Jacques Pienaar 14489b5a8a Remove unnecessary headers from mlir-opt.
PiperOrigin-RevId: 238639013
2019-03-29 17:20:12 -07:00
River Riddle 076a7350e2 Add an instrumentation for conditionally printing the IR before and after pass execution. This instrumentation can be added directly to the PassManager via 'enableIRPrinting'. mlir-opt exposes access to this instrumentation via the following flags:
* print-ir-before=(comma-separated-pass-list)
  - Print the IR before each of the passes provided within the pass list.
* print-ir-before-all
  - Print the IR before every pass in the pipeline.
* print-ir-after=(comma-separated-pass-list)
  - Print the IR after each of the passes provided within the pass list.
* print-ir-after-all
  - Print the IR after every pass in the pipeline.
* print-ir-module-scope
  - Always print the Module IR, even for non module passes.

PiperOrigin-RevId: 238523649
2019-03-29 17:19:57 -07:00
River Riddle 6558f80c8d Refactor pass timing so that it is toggled on the passmanager via 'enableTiming'. This also makes the pipeline view the default display mode.
PiperOrigin-RevId: 238079916
2019-03-29 17:15:42 -07:00
River Riddle 0cc212f2b7 Ensure that pass timing is the last added pass instrumentation. This also updates the PassInstrumentor to iterate in reverse for the "after" hooks. This ensures that the instrumentations run in a stack like fashion.
PiperOrigin-RevId: 237840808
2019-03-29 17:11:56 -07:00
River Riddle e46ba31c66 Add a new instrumentation for timing pass and analysis execution. This is made available in mlir-opt via the 'pass-timing' and 'pass-timing-display' flags. The 'pass-timing-display' flag toggles between the different available display modes for the timing results. The current display modes are 'list' and 'pipeline', with 'list' representing the default.
Below shows the output for an example mlir-opt command line.

mlir-opt foo.mlir -verify-each=false -cse -canonicalize -cse -cse -pass-timing

list view (-pass-timing-display=list):
* In this mode the results are displayed in a list sorted by total time; with each pass/analysis instance aggregated into one unique result. This mode is similar to the output of 'time-passes' in llvm-opt.

===-------------------------------------------------------------------------===
                      ... Pass execution timing report ...
===-------------------------------------------------------------------------===
  Total Execution Time: 0.0097 seconds (0.0096 wall clock)

   ---User Time---   --System Time--   --User+System--   ---Wall Time---  --- Name ---
   0.0051 ( 58.3%)   0.0001 ( 12.2%)   0.0052 ( 53.8%)   0.0052 ( 53.8%)  Canonicalizer
   0.0025 ( 29.1%)   0.0005 ( 58.2%)   0.0031 ( 31.9%)   0.0031 ( 32.0%)  CSE
   0.0011 ( 12.6%)   0.0003 ( 29.7%)   0.0014 ( 14.3%)   0.0014 ( 14.2%)  DominanceInfo
   0.0087 (100.0%)   0.0009 (100.0%)   0.0097 (100.0%)   0.0096 (100.0%)  Total

pipeline view (-pass-timing-display=pipeline):
* In this mode the results are displayed in a nested pipeline view that mirrors the internal pass pipeline that is being executed in the pass manager. This view is useful for understanding specifically which parts of the pipeline are taking the most time, and can also be used to identify when analyses are being invalidated and recomputed.

===-------------------------------------------------------------------------===
                      ... Pass execution timing report ...
===-------------------------------------------------------------------------===
  Total Execution Time: 0.0082 seconds (0.0081 wall clock)

   ---User Time---   --System Time--   --User+System--   ---Wall Time---  --- Name ---
   0.0042 (100.0%)   0.0039 (100.0%)   0.0082 (100.0%)   0.0081 (100.0%)  Function Pipeline
   0.0005 ( 11.6%)   0.0008 ( 21.1%)   0.0013 ( 16.1%)   0.0013 ( 16.2%)    CSE
   0.0002 (  5.0%)   0.0004 (  9.3%)   0.0006 (  7.0%)   0.0006 (  7.0%)      (A) DominanceInfo
   0.0026 ( 61.8%)   0.0018 ( 45.6%)   0.0044 ( 54.0%)   0.0044 ( 54.1%)    Canonicalizer
   0.0005 ( 11.7%)   0.0005 ( 13.0%)   0.0010 ( 12.3%)   0.0010 ( 12.4%)    CSE
   0.0003 (  6.1%)   0.0003 (  8.3%)   0.0006 (  7.2%)   0.0006 (  7.1%)      (A) DominanceInfo
   0.0002 (  3.8%)   0.0001 (  2.8%)   0.0003 (  3.3%)   0.0003 (  3.3%)    CSE
   0.0042 (100.0%)   0.0039 (100.0%)   0.0082 (100.0%)   0.0081 (100.0%)  Total

PiperOrigin-RevId: 237825367
2019-03-29 17:11:25 -07:00
River Riddle f427bddd06 Update the PassManager infrastructure to return Status instead of bool.
PiperOrigin-RevId: 237261205
2019-03-29 17:05:51 -07:00
River Riddle 50efe0fc85 Add a 'verifyPasses' flag to the PassManager that specifies if the IR should be verified after each pass. This also adds a "verify-each" flag to mlir-opt to optionally disable running the verifier after each pass.
PiperOrigin-RevId: 236703760
2019-03-29 16:55:35 -07:00
River Riddle ed5fe2098b Remove PassResult and have the runOnFunction/runOnModule functions return void instead. To signal a pass failure, passes should now invoke the 'signalPassFailure' method. This provides the equivalent functionality when needed, but isn't an intrusive part of the API like PassResult.
PiperOrigin-RevId: 236202029
2019-03-29 16:50:44 -07:00
River Riddle 091ff3dc3f Add support for registering pass pipelines to the PassRegistry. This is done by providing a static registration facility PassPipelineRegistration that works similarly to PassRegistration except for it also takes a function that will add necessary passes to a provided PassManager.
void pipelineBuilder(PassManager &pm) {
      pm.addPass(new MyPass());
      pm.addPass(new MyOtherPass());
  }

  static PassPipelineRegistration Unused("unused", "Unused pass", pipelineBuilder);

This is also useful for registering specializations of existing passes:

  Pass *createFooPass10() { return new FooPass(10); }

  static PassPipelineRegistration Unused("unused", "Unused pass", createFooPass10);

PiperOrigin-RevId: 235996282
2019-03-29 16:48:29 -07:00
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
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
Lei Zhang ac5a50e1e4 Extract openInputFile() into Support/FileUtilities
Multiple binaries have the needs to open input files. Use this function
to de-duplicate the code.

Also changed openOutputFile() to return errors using std::string since
it is a library call and accessing I/O in library call is not friendly.

PiperOrigin-RevId: 228878221
2019-03-29 15:09:11 -07:00
Chris Lattner 4fbcd1ac52 Minor renamings: Trim the "Stmt" prefix off
StmtSuccessorIterator/StmtSuccessorIterator, and rename and move the
CFGFunctionViewGraph pass to ViewFunctionGraph.

This is step 13/n towards merging instructions and statements, NFC.

PiperOrigin-RevId: 227069438
2019-03-29 14:40:51 -07:00
Chris Lattner 776b035646 Eliminate the Instruction, BasicBlock, CFGFunction, MLFunction, and ExtFunction classes, using the Statement/StmtBlock hierarchy and Function instead.
This *only* changes the internal data structures, it does not affect the user visible syntax or structure of MLIR code.  Function gets new "isCFG()" sorts of predicates as a transitional measure.

This patch is gross in a number of ways, largely in an effort to reduce the amount of mechanical churn in one go.  It introduces a bunch of using decls to keep the old names alive for now, and a bunch of stuff needs to be renamed.

This is step 10/n towards merging instructions and statements, NFC.

PiperOrigin-RevId: 227044402
2019-03-29 14:39:49 -07:00
Jacques Pienaar f10f48ee63 Convert MLIR DiagnosticKind to LLVM DiagKind when emitting diagnostic via mlir-opt.
PiperOrigin-RevId: 222147297
2019-03-29 14:02:02 -07:00
Smit Hinsu a894bfdfd6 Update split marker for split-input-file option to be more restrictive
This is to allow usage of comment blocks along with splits in test cases.
For example, "Function Control Flow Lowering" comment block in
raise-control-flow.mlir

TESTED with existing unit tests

PiperOrigin-RevId: 221214451
2019-03-29 13:56:05 -07:00
River Riddle 2fa4bc9fc8 Implement value type abstraction for locations.
Value type abstraction for locations differ from others in that a Location can NOT be null. NOTE: dyn_cast returns an Optional<T>.

PiperOrigin-RevId: 220682078
2019-03-29 13:52:31 -07:00
Jacques Pienaar 6f0fb22723 Add static pass registration
Add static pass registration and change mlir-opt to use it. Future work is needed to refactor the registration for PassManager usage.

Change build targets to alwayslink to enforce registration.

PiperOrigin-RevId: 220390178
2019-03-29 13:49:34 -07:00
Uday Bondhugula 6cd5d5c544 Introduce loop tiling code generation (hyper-rectangular case)
- simple perfectly nested band tiling with fixed tile sizes.
- only the hyper-rectangular case is handled, with other limitations of
  getIndexSet applying (constant loop bounds, etc.);  once
  the latter utility is extended, tiled code generation should become more
  general.
- Add FlatAffineConstraints::isHyperRectangular()

PiperOrigin-RevId: 220324933
2019-03-29 13:49:05 -07:00
Jacques Pienaar 5e01000d46 Start TFLite legalizer pass
Start of TFLite legalizer pass. Currently focussed on macro expanding ops, limited to what is registered directly in a separate pass (this should instead be a general pass), no querying of what gets produced, the matching is string based instead of using the ops proper (the matching TF ops should be defined) etc. This is a step to enable prototyping. In addition to the above shortcomings, the legalizer is very verbose in this form and should instead be driven by autogenerated patterns (same is true for the op builders too). But this starts from the explicit form and extracting out commonality in follow up.

Add definition for tfl.relu for basic selection of fused relu add.

PiperOrigin-RevId: 220287087
2019-03-29 13:48:50 -07:00
MLIR Team 239e328913 Adds MemRefDependenceCheck analysis pass, plus multiple dependence check tests.
Adds equality constraints to dependence constraint system for accesses using dims/symbols where the defining operation of the dim/symbol is a constant.

PiperOrigin-RevId: 219814740
2019-03-29 13:48:05 -07:00
MLIR Team f28e4df666 Adds a dependence check to test whether two accesses to the same memref access the same element.
- Builds access functions and iterations domains for each access.
- Builds dependence polyhedron constraint system which has equality constraints for equated access functions and inequality constraints for iteration domain loop bounds.
- Runs elimination on the dependence polyhedron to test if no dependence exists between the accesses.
- Adds a trivial LoopFusion transformation pass with a simple test policy to test dependence between accesses to the same memref in adjacent loops.
- The LoopFusion pass will be extended in subsequent CLs.

PiperOrigin-RevId: 219630898
2019-03-29 13:47:13 -07:00
Uday Bondhugula 8201e19e3d Introduce memref bound checking.
Introduce analysis to check memref accesses (in MLFunctions) for out of bound
ones. It works as follows:

$ mlir-opt -memref-bound-check test/Transforms/memref-bound-check.mlir

/tmp/single.mlir:10:12: error: 'load' op memref out of upper bound access along dimension tensorflow/mlir#1
      %x = load %A[%idxtensorflow/mlir#0, %idxtensorflow/mlir#1] : memref<9 x 9 x i32>
           ^
/tmp/single.mlir:10:12: error: 'load' op memref out of lower bound access along dimension tensorflow/mlir#1
      %x = load %A[%idxtensorflow/mlir#0, %idxtensorflow/mlir#1] : memref<9 x 9 x i32>
           ^
/tmp/single.mlir:10:12: error: 'load' op memref out of upper bound access along dimension tensorflow/mlir#2
      %x = load %A[%idxtensorflow/mlir#0, %idxtensorflow/mlir#1] : memref<9 x 9 x i32>
           ^
/tmp/single.mlir:10:12: error: 'load' op memref out of lower bound access along dimension tensorflow/mlir#2
      %x = load %A[%idxtensorflow/mlir#0, %idxtensorflow/mlir#1] : memref<9 x 9 x i32>
           ^
/tmp/single.mlir:12:12: error: 'load' op memref out of upper bound access along dimension tensorflow/mlir#1
      %y = load %B[%idy] : memref<128 x i32>
           ^
/tmp/single.mlir:12:12: error: 'load' op memref out of lower bound access along dimension tensorflow/mlir#1
      %y = load %B[%idy] : memref<128 x i32>
           ^
#map0 = (d0, d1) -> (d0, d1)
#map1 = (d0, d1) -> (d0 * 128 - d1)
mlfunc @test() {
  %0 = alloc() : memref<9x9xi32>
  %1 = alloc() : memref<128xi32>
  for %i0 = -1 to 9 {
    for %i1 = -1 to 9 {
      %2 = affine_apply #map0(%i0, %i1)
      %3 = load %0[%2tensorflow/mlir#0, %2tensorflow/mlir#1] : memref<9x9xi32>
      %4 = affine_apply #map1(%i0, %i1)
      %5 = load %1[%4] : memref<128xi32>
    }
  }
  return
}

- Improves productivity while manually / semi-automatically developing MLIR for
  testing / prototyping; also provides an indirect way to catch errors in
  transformations.

- This pass is an easy way to test the underlying affine analysis
  machinery including low level routines.

Some code (in getMemoryRegion()) borrowed from @andydavis cl/218263256.

While on this:

- create mlir/Analysis/Passes.h; move Pass.h up from mlir/Transforms/ to mlir/

- fix a bug in AffineAnalysis.cpp::toAffineExpr

TODO: extend to non-constant loop bounds (straightforward). Will transparently
work for all accesses once floordiv, mod, ceildiv are supported in the
AffineMap -> FlatAffineConstraints conversion.
PiperOrigin-RevId: 219397961
2019-03-29 13:46:08 -07:00
Uday Bondhugula 80610c2f49 Introduce Fourier-Motzkin variable elimination + other cleanup/support
- 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
2019-03-29 13:38:24 -07:00
Nicolas Vasilache 3013dadb7c [MLIR] Basic infrastructure for vectorization test
This CL implements a very simple loop vectorization **test** and the basic
infrastructure to support it.

The test simply consists in:
1. matching the loops in the MLFunction and all the Load/Store operations
nested under the loop;
2. testing whether all the Load/Store are contiguous along the innermost
memory dimension along that particular loop. If any reference is
non-contiguous (i.e. the ForStmt SSAValue appears in the expression), then
the loop is not-vectorizable.

The simple test above can gradually be extended with more interesting
behaviors to account for the fact that a layout permutation may exist that
enables contiguity etc. All these will come in due time but it is worthwhile
noting that the test already supports detection of outer-vetorizable loops.

In implementing this test, I also added a recursive MLFunctionMatcher and some
sugar that can capture patterns
such as `auto gemmLike = Doall(Doall(Red(LoadStore())))` and allows iterating
on the matched IR structures. For now it just uses in order traversal but
post-order DFS will be useful in the future once IR rewrites start occuring.

One may note that the memory management design decision follows a different
pattern from MLIR. After evaluating different designs and how they quickly
increase cognitive overhead, I decided to opt for the simplest solution in my
view: a class-wide (threadsafe) RAII context.

This way, a pass that needs MLFunctionMatcher can just have its own locally
scoped BumpPtrAllocator and everything is cleaned up when the pass is destroyed.
If passes are expected to have a longer lifetime, then the contexts can easily
be scoped inside the runOnMLFunction call and storage lifetime reduced.
Lastly, whatever the scope of threading (module, function, pass), this is
expected to also be future-proof wrt concurrency (but this is a detail atm).

PiperOrigin-RevId: 217622889
2019-03-29 13:32:13 -07:00