Commit Graph

52 Commits

Author SHA1 Message Date
Stephen Neuendorffer 628288658c [MLIR] Add RegionKindInterface
Some dialects have semantics which is not well represented by common
SSA structures with dominance constraints.  This patch allows
operations to declare the 'kind' of their contained regions.
Currently, two kinds are allowed: "SSACFG" and "Graph".  The only
difference between them at the moment is that SSACFG regions are
required to have dominance, while Graph regions are not required to
have dominance.  The intention is that this Interface would be
generated by ODS for existing operations, although this has not yet
been implemented. Presumably, if someone were interested in code
generation, we might also have a "CFG" dialect, which defines control
flow, but does not require SSA.

The new behavior is mostly identical to the previous behavior, since
registered operations without a RegionKindInterface are assumed to
contain SSACFG regions.  However, the behavior has changed for
unregistered operations.  Previously, these were checked for
dominance, however the new behavior allows dominance violations, in
order to allow the processing of unregistered dialects with Graph
regions.  One implication of this is that regions in unregistered
operations with more than one op are no longer CSE'd (since it
requires dominance info).

I've also reorganized the LangRef documentation to remove assertions
about "sequential execution", "SSA Values", and "Dominance".  Instead,
the core IR is simply "ordered" (i.e. totally ordered) and consists of
"Values".  I've also clarified some things about how control flow
passes between blocks in an SSACFG region. Control Flow must enter a
region at the entry block and follow terminator operation successors
or be returned to the containing op.  Graph regions do not define a
notion of control flow.

see discussion here:
https://llvm.discourse.group/t/rfc-allowing-dialects-to-relax-the-ssa-dominance-condition/833/53

Differential Revision: https://reviews.llvm.org/D80358
2020-07-15 14:27:05 -07:00
Nicolai Hähnle 3fa989d4fd DomTree: remove explicit use of DomTreeNodeBase::iterator
Summary:
Almost all uses of these iterators, including implicit ones, really
only need the const variant (as it should be). The only exception is
in NewGVN, which changes the order of dominator tree child nodes.

Change-Id: I4b5bd71e32d71b0c67b03d4927d93fe9413726d4

Reviewers: arsenm, RKSimon, mehdi_amini, courbet, rriddle, aartbik

Subscribers: wdng, Prazek, hiraditya, kuhar, rogfer01, rriddle, jpienaar, shauheen, antiagainst, nicolasvasilache, arpith-jacob, mgester, lucyrfox, aartbik, liufengdb, stephenneuendorffer, Joonsoo, grosul1, vkmr, Kayjukh, jurahul, msifontes, cfe-commits, llvm-commits

Tags: #clang, #mlir, #llvm

Differential Revision: https://reviews.llvm.org/D83087
2020-07-08 18:18:49 +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
Stephen Neuendorffer 57818885be [MLIR] Move Verifier and Dominance Analysis from /Analysis to /IR
These libraries are distinct from other things in Analysis in that they
operate only on core IR concepts.  This also simplifies dependencies
so that Dialect -> Analysis -> Parser -> IR.  Previously, the parser depended
on portions of the the Analysis directory as well, which sometimes
caused issues with the way the cmake makefile generator discovers
dependencies on generated files during compilation.

Differential Revision: https://reviews.llvm.org/D79240
2020-05-01 20:01:46 -07:00
River Riddle df00e466da [mlir] Move the operation equivalence out of CSE and into OperationSupport
This provides a general hash and comparison for checking if two operations are equivalent. This revision also optimizes the handling of result types to take advantage of how result types are stored on the operation.

Differential Revision: https://reviews.llvm.org/D79029
2020-04-29 16:48:15 -07:00
Jacques Pienaar 5439582781 Rename NamedAttributeList to MutableDictionaryAttr
Makes the relationship and function clearer. Accordingly rename getAttrList to getMutableAttrDict.

Differential Revision: https://reviews.llvm.org/D79125
2020-04-29 14:58:02 -07:00
River Riddle 1834ad4a69 [mlir][Pass] Update the PassGen to generate base classes instead of utilities
Summary:
This is much cleaner, and fits the same structure as many other tablegen backends. This was not done originally as the CRTP in the pass classes made it overly verbose/complex.

Differential Revision: https://reviews.llvm.org/D77367
2020-04-07 14:08:52 -07:00
River Riddle 80aca1eaf7 [mlir][Pass] Remove the use of CRTP from the Pass classes
This revision removes all of the CRTP from the pass hierarchy in preparation for using the tablegen backend instead. This creates a much cleaner interface in the C++ code, and naturally fits with the rest of the infrastructure. A new utility class, PassWrapper, is added to replicate the existing behavior for passes not suitable for using the tablegen backend.

Differential Revision: https://reviews.llvm.org/D77350
2020-04-07 14:08:52 -07:00
River Riddle 9a277af2d4 [mlir][Pass] Add support for generating pass utilities via tablegen
This revision adds support for generating utilities for passes such as options/statistics/etc. that can be inferred from the tablegen definition. This removes additional boilerplate from the pass, and also makes it easier to remove the reliance on the pass registry to provide certain things(e.g. the pass argument).

Differential Revision: https://reviews.llvm.org/D76659
2020-04-01 02:10:46 -07:00
River Riddle 8155e41ac6 [mlir][Pass] Add a tablegen backend for defining Pass information
This will greatly simplify a number of things related to passes:
* Enables generation of pass registration
* Enables generation of boiler plate pass utilities
* Enables generation of pass documentation

This revision focuses on adding the basic structure and adds support for generating the registration for passes in the Transforms/ directory. Future revisions will add more support and move more passes over.

Differential Revision: https://reviews.llvm.org/D76656
2020-04-01 02:10:46 -07:00
River Riddle 0ddba0bd59 [mlir][SideEffects] Replace HasNoSideEffect with the memory effect interfaces.
HasNoSideEffect can now be implemented using the MemoryEffectInterface, removing the need to check multiple things for the same information. This also removes an easy foot-gun for users as 'Operation::hasNoSideEffect' would ignore operations that dynamically, or recursively, have no side effects. This also leads to an immediate improvement in some of the existing users, such as DCE, now that they have access to more information.

Differential Revision: https://reviews.llvm.org/D76036
2020-03-12 14:26:15 -07:00
River Riddle d5f53253a0 [mlir][SideEffects] Mark the CFG only terminator operations as NoSideEffect
These terminator operations don't really have any side effects, and this allows for more accurate side-effect analysis for region operations. For example, currently we can't detect like a loop.for or affine.for are dead because the affine.terminator is "side effecting".

Note: Marking as NoSideEffect doesn't mean that these operations can be opaquely erased.

Differential Revision: https://reviews.llvm.org/D75888
2020-03-12 14:26:14 -07:00
River Riddle aff4ed7326 [mlir][NFC] Update Operation::getResultTypes to use ArrayRef<Type> instead of iterator_range.
Summary: The new internal representation of operation results now allows for accessing the result types to be more efficient. Changing the API to ArrayRef is more efficient and removes the need to explicitly materialize vectors in several places.

Differential Revision: https://reviews.llvm.org/D73429
2020-01-27 19:57:48 -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 33a64540ad Add support for instance specific pass statistics.
Statistics are a way to keep track of what the compiler is doing and how effective various optimizations are. It is useful to see what optimizations are contributing to making a particular program run faster. Pass-instance specific statistics take this even further as you can see the effect of placing a particular pass at specific places within the pass pipeline, e.g. they could help answer questions like "what happens if I run CSE again here".

Statistics can be added to a pass by simply adding members of type 'Pass::Statistics'. This class takes as a constructor arguments: the parent pass pointer, a name, and a description. Statistics can be dumped by the pass manager in a similar manner to how pass timing information is dumped, i.e. via PassManager::enableStatistics programmatically; or -pass-statistics and -pass-statistics-display via the command line pass manager options.

Below is an example:

struct MyPass : public OperationPass<MyPass> {
  Statistic testStat{this, "testStat", "A test statistic"};

  void runOnOperation() {
    ...
    ++testStat;
    ...
  }
};

$ mlir-opt -pass-pipeline='func(my-pass,my-pass)' foo.mlir -pass-statistics

Pipeline Display:
===-------------------------------------------------------------------------===
                         ... Pass statistics report ...
===-------------------------------------------------------------------------===
'func' Pipeline
  MyPass
    (S) 15 testStat - A test statistic
  MyPass
    (S)  6 testStat - A test statistic

List Display:
===-------------------------------------------------------------------------===
                         ... Pass statistics report ...
===-------------------------------------------------------------------------===
MyPass
  (S) 21 testStat - A test statistic

PiperOrigin-RevId: 284022014
2019-12-05 11:53:28 -08:00
River Riddle 6f895bec7d [CSE] NFC: Hash the attribute dictionary pointer instead of the list of attributes.
PiperOrigin-RevId: 283810829
2019-12-04 12:32:08 -08:00
River Riddle 2b61b7979e Convert the Canonicalize and CSE passes to generic Operation Passes.
This allows for them to be used on other non-function, or even other function-like, operations. The algorithms are already generic, so this is simply changing the derived pass type. The majority of this change is just ensuring that the nesting of these passes remains the same, as the pass manager won't auto-nest them anymore.

PiperOrigin-RevId: 276573038
2019-10-24 15:01:09 -07:00
River Riddle f1b100c77b NFC: Finish replacing FunctionPassBase/ModulePassBase with OpPassBase.
These directives were temporary during the generalization of FunctionPass/ModulePass to OpPass.

PiperOrigin-RevId: 268970259
2019-09-13 13:34:27 -07:00
Jacques Pienaar 79f53b0cf1 Change from llvm::make_unique to std::make_unique
Switch to C++14 standard method as llvm::make_unique has been removed (
https://reviews.llvm.org/D66259). Also mark some targets as c++14 to ease next
integrates.

PiperOrigin-RevId: 263953918
2019-08-17 11:06:03 -07:00
Mehdi Amini 926fb685de Express ownership transfer in PassManager API through std::unique_ptr (NFC)
Since raw pointers are always passed around for IR construct without
implying any ownership transfer, it can be error prone to have implicit
ownership transferred the same way.
For example this code can seem harmless:

  Pass *pass = ....
  pm.addPass(pass);
  pm.addPass(pass);
  pm.run(module);

PiperOrigin-RevId: 263053082
2019-08-12 19:13:12 -07:00
River Riddle 8089f93746 Add utility 'replaceAllUsesWith' methods to Operation.
These methods will allow replacing the uses of results with an existing operation, with the same number of results, or a range of values. This removes a number of hand-rolled result replacement loops and simplifies replacement for operations with multiple results.

PiperOrigin-RevId: 262206600
2019-08-07 13:48:52 -07:00
River Riddle b67cab4c44 Update CSE to respect nested regions that are isolated from above. This cl also removes the unused 'NthRegionIsIsolatedFromAbove' trait as it was replaced with a more general 'IsIsolatedFromAbove'.
PiperOrigin-RevId: 254709704
2019-06-24 13:44:53 -07:00
River Riddle 99b87c9707 Replace usages of Instruction with Operation in the Transforms/ directory.
PiperOrigin-RevId: 240636130
2019-03-29 17:47:26 -07:00
River Riddle af45236c70 Add experimental support for multi-threading the pass manager. This adds support for running function pipelines on functions across multiple threads, and is guarded by an off-by-default flag 'experimental-mt-pm'. There are still quite a few things that need to be done before multi-threading is ready for general use(e.g. pass-timing), but this allows for those things to be tested in a multi-threaded environment.
PiperOrigin-RevId: 240489002
2019-03-29 17:44:08 -07:00