30 Commits

Author SHA1 Message Date
Stephan Herhut
4348d8ab7f [mlir][math] Split off the math dialect.
This does not split transformations, yet. Those will be done as future clean ups.

Differential Revision: https://reviews.llvm.org/D96272
2021-02-12 10:55:12 +01:00
Lei Zhang
5b7619c90b [mlir] Fix scf.for single iteration canonicalization check
We should be check whether lb + step >= ub to determine
whether this is a single iteration. Previously we were
checking lb + lb >= ub.

Reviewed By: ftynse

Differential Revision: https://reviews.llvm.org/D95440
2021-02-02 18:30:50 -05:00
Lei Zhang
a2e791e396 Revert "[mlir] Fix scf.for single iteration canonicalization check"
This reverts commit b2b35697dc5172ab1e815e08c0a2714f2a1a9330.
It gotten accidentially landed before LGTM.
2021-02-02 11:13:39 -05:00
Lei Zhang
b2b35697dc [mlir] Fix scf.for single iteration canonicalization check
We should be check whether lb + step >= ub to determine
whether this is a single iteration. Previously we were
checking lb + lb >= ub.

Differential Revision: https://reviews.llvm.org/D95440
2021-02-02 11:08:56 -05:00
River Riddle
93592b726c [mlir][OpFormatGen] Format enum attribute cases as keywords when possible
In the overwhelmingly common case, enum attribute case strings represent valid identifiers in MLIR syntax. This revision updates the format generator to format as a keyword in these cases, removing the need to wrap values in a string. The parser still retains the ability to parse the string form, but the printer will use the keyword form when applicable.

Differential Revision: https://reviews.llvm.org/D94575
2021-01-14 11:35:49 -08:00
Rahul Joshi
fe7fdcac87 [MLIR] Fix parseFunctionLikeOp() to fail parsing empty regions
- Change parseOptionalRegion to return an OptionalParseResult.
- Change parseFunctionLikeOp() to fail parsing if the function body was parsed but was
  empty.
- See https://llvm.discourse.group/t/funcop-parsing-bug/2164

Differential Revision: https://reviews.llvm.org/D91886
2020-12-04 09:09:59 -08:00
Frederik Gossen
6484567f14 [MLIR][SCF] Find all innermost loops for parallel loop tiling
Overcome the assumption that parallel loops are only nested in other parallel
loops.

Differential Revision: https://reviews.llvm.org/D92188
2020-11-27 10:08:56 +01:00
Alex Zinenko
31a233d463 [mlir] canonicalize away zero-iteration SCF for loops
An SCF 'for' loop does not iterate if its lower bound is equal to its upper
bound. Remove loops where both bounds are the same SSA value as such bounds are
guaranteed to be equal. Similarly, remove 'parallel' loops where at least one
pair of respective lower/upper bounds is specified by the same SSA value.

Reviewed By: gysit

Differential Revision: https://reviews.llvm.org/D91880
2020-11-23 15:04:31 +01:00
Alex Zinenko
18d0f7d5c3 [mlir] add canonicalization patterns for trivial SCF 'for' and 'if'
Add canoncalization patterns to remove zero-iteration 'for' loops, replace
single-iteration 'for' loops with their bodies; remove known-false conditionals
with no 'else' branch and replace conditionals with known value by the
respective region. Although similar transformations are performed at the CFG
level, not all flows reach that level, e.g., the GPU flow may want to remove
single-iteration loops before deciding on loop mapping to thread dimensions.

Reviewed By: herhut

Differential Revision: https://reviews.llvm.org/D91865
2020-11-20 19:04:39 +01:00
Rahul Joshi
b7382ed3fe [MLIR] Extend Symbol verification to reject public symbol declarations.
- Extend the Symbol interface with `isDeclaration` to identify operations that declare
  a symbol as opposed to define it.
- Extend verification to disallow public declarations as per the discussion in
   https://llvm.discourse.group/t/rfc-symbol-definition-declaration-x-visibility-checks/2140
- Adopt the new interface for `FuncOp` and fix test and code to not have/create public
  function declarations.

Differential Revision: https://reviews.llvm.org/D91456
2020-11-16 16:05:32 -08:00
Nicolas Vasilache
f202d32216 [mlir][SCF] Add canonicalization pattern for scf::For to eliminate yields that just forward.
For instance:
```
func @for_yields_3(%lb : index, %ub : index, %step : index) -> (i32, i32, i32) {
  %a = call @make_i32() : () -> (i32)
  %b = call @make_i32() : () -> (i32)
  %r:3 = scf.for %i = %lb to %ub step %step iter_args(%0 = %a, %1 = %a, %2 = %b) -> (i32, i32, i32) {
    %c = call @make_i32() : () -> (i32)
    scf.yield %0, %c, %2 : i32, i32, i32
  }
  return %r#0, %r#1, %r#2 : i32, i32, i32
}
```

Canonicalizes as:
```
  func @for_yields_3(%arg0: index, %arg1: index, %arg2: index) -> (i32, i32, i32) {
    %0 = call @make_i32() : () -> i32
    %1 = call @make_i32() : () -> i32
    %2 = scf.for %arg3 = %arg0 to %arg1 step %arg2 iter_args(%arg4 = %0) -> (i32) {
      %3 = call @make_i32() : () -> i32
      scf.yield %3 : i32
    }
    return %0, %2, %1 : i32, i32, i32
  }
```

Differential Revision: https://reviews.llvm.org/D90745
2020-11-04 11:36:27 +00:00
Alex Zinenko
79716559b5 [mlir] Add a generic while/do-while loop to the SCF dialect
The new construct represents a generic loop with two regions: one executed
before the loop condition is verifier and another after that. This construct
can be used to express both a "while" loop and a "do-while" loop, depending on
where the main payload is located. It is intended as an intermediate
abstraction for lowering, which will be added later. This form is relatively
easy to target from higher-level abstractions and supports transformations such
as loop rotation and LICM.

Differential Revision: https://reviews.llvm.org/D90255
2020-11-04 09:43:13 +01:00
River Riddle
a463ea50a4 [mlir][ASM] Refactor how attribute/type aliases are specified.
Previously they were separated into "instance" and "kind" aliases, and also required that the dialect know ahead of time all of the instances that would have a corresponding alias. This approach was very clunky and not ergonomic to interact with. The new approach is to provide the dialect with an instance  of an attribute/type to provide an alias for, fully replacing the original split approach.

Differential Revision: https://reviews.llvm.org/D89354
2020-10-30 00:39:46 -07:00
Sean Silva
1ce7040359 [mlir] Properly handle recursive bufferization for scf.for/scf.if
This fixes a subtle issue, described in the comment starting with
"Clone the op without the regions and inline the regions from the old op",
which prevented this conversion from working on non-trivial examples.

Differential Revision: https://reviews.llvm.org/D90203
2020-10-28 14:16:56 -07:00
Sean Silva
f0292ede9b [mlir] Add structural type conversions for SCF dialect.
A "structural" type conversion is one where the underlying ops are
completely agnostic to the actual types involved and simply need to update
their types. An example of this is scf.if -- the scf.if op and the
corresponding scf.yield ops need to update their types accordingly to the
TypeConverter, but otherwise don't care what type conversions are happening.

To test the structural type conversions, it is convenient to define a
bufferize pass for a dialect, which exercises them nicely.

Differential Revision: https://reviews.llvm.org/D89757
2020-10-21 11:58:27 -07:00
Tobias Gysi
93377888ae [mlir] add scf.if op canonicalization pattern that removes unused results
The patch adds a canonicalization pattern that removes the unused results of scf.if operation. As a result, cse may remove unused computations in the then and else regions of the scf.if operation.

Reviewed By: mehdi_amini

Differential Revision: https://reviews.llvm.org/D89029
2020-10-11 10:40:28 +02:00
Lubomir Litchev
320624784c [NFC] Follow up on D87111 - Add an option for unrolling loops up to a factor - CR issues addressed.
Addressed some CR issues pointed out in D87111. Formatting and other nits.
The original Diff D87111 - Add an option for unrolling loops up to a factor.

Reviewed By: bondhugula

Differential Revision: https://reviews.llvm.org/D87313
2020-09-11 08:12:44 -07:00
Sean Silva
be35264ab5 Wordsmith RegionBranchOpInterface verification errors
I was having a lot of trouble parsing the messages. In particular, the
messages like:

```
<stdin>:3:8: error: 'scf.if' op  along control flow edge from Region #0 to scf.if source #1 type '!npcomprt.tensor' should match input #1 type 'tensor<?xindex>'
```

In particular, one thing that kept catching me was parsing the "to scf.if
source #1 type" as one thing, but really it is
"to parent results: source type #1".

Differential Revision: https://reviews.llvm.org/D87334
2020-09-09 12:50:23 -07:00
Lubomir Litchev
e2394245eb Add an option for unrolling loops up to a factor.
Currently, there is no option to allow for unrolling a loop up to a specific factor (specified by the user).
The code for doing that is there and there are benefits when unrolling is done  to smaller loops (smaller than the factor specified).

Reviewed By: bondhugula

Differential Revision: https://reviews.llvm.org/D87111
2020-09-08 09:23:38 -07:00
Rahul Joshi
a3ad8f92b4 [MLIR] Add type checking capability to RegionBranchOpInterface
- Add function `verifyTypes` that Op's can call to do type checking verification
  along the control flow edges described the Op's RegionBranchOpInterface.
- We cannot rely on the verify methods on the OpInterface because the interface
  functions assume valid Ops, so they may crash if invoked on unverified Ops.
  (For example, scf.for getSuccessorRegions() calls getRegionIterArgs(), which
  dereferences getBody() block. If the scf.for is invalid with no body, this
  can lead to a segfault). `verifyTypes` can be called post op-verification to
  avoid this.

Differential Revision: https://reviews.llvm.org/D82829
2020-07-15 11:14:07 -07:00
Mehdi Amini
f54d0e36be Rename xla_lhlo.terminator into return in SCF parallel loop test (NFC)
It seems that these were inserted here inadvertently instead of using
standard `return`.
2020-07-08 04:05:43 +00:00
Rahul Joshi
52af9c59e3 [MLIR] Add a NoRegionArguments trait
- This trait will verify that all regions attached to an Op have no arguments
- Fixes https://bugs.llvm.org/show_bug.cgi?id=46521 : Add trait NoRegionArguments

Differential Revision: https://reviews.llvm.org/D83016
2020-07-06 09:05:38 -07:00
Tobias Gysi
48f1d4fcd2 [mlir] parallel loop canonicalization
Summary:
The patch introduces a canonicalization pattern for parallel loops. The pattern removes single-iteration loop dimensions if the loop bounds and steps are constants.

Reviewers: herhut, ftynse

Reviewed By: herhut

Subscribers: mehdi_amini, rriddle, jpienaar, shauheen, antiagainst, nicolasvasilache, arpith-jacob, mgester, lucyrfox, aartbik, liufengdb, stephenneuendorffer, Joonsoo, grosul1, Kayjukh, jurahul, msifontes

Tags: #mlir

Differential Revision: https://reviews.llvm.org/D82191
2020-06-26 09:57:08 +02:00
Tobias Gysi
cd73081605 [mlir] parallel loop tiling optimization for loops with static bounds
Summary: The patch optimizes the tiling of parallel loops with static bounds if the number of loop iterations is an integer multiple of the tile size.

Reviewers: herhut, ftynse, bondhugula

Reviewed By: herhut, ftynse

Subscribers: bondhugula, mehdi_amini, rriddle, jpienaar, shauheen, antiagainst, nicolasvasilache, arpith-jacob, mgester, lucyrfox, aartbik, liufengdb, stephenneuendorffer, Joonsoo, grosul1, frgossen, Kayjukh, jurahul, msifontes

Tags: #mlir

Differential Revision: https://reviews.llvm.org/D82003
2020-06-25 09:21:24 +02:00
Stephan Herhut
4bcd08eb1c [mlir] Add for loop specialization
Summary:
We already had a parallel loop specialization pass that is used to
enable unrolling and consecutive vectorization by rewriting loops
whose bound is defined as a min of a constant and a dynamic value
into a loop with static bound (the constant) and the minimum as
bound, wrapped into a conditional to dispatch between the two.
This adds the same rewriting for for loops.

Differential Revision: https://reviews.llvm.org/D82189
2020-06-22 10:14:17 +02:00
Stephan Herhut
1e60678c1f [MLIR] Fix parallel loop tiling.
Summary:
Parallel loop tiling did not properly compute the updated loop
indices when tiling, which lead to wrong results.

Differential Revision: https://reviews.llvm.org/D82013
2020-06-17 23:30:13 +02:00
Frederik Gossen
904f91db5f [MLIR][Standard] Make the dim operation index an operand.
Allow for dynamic indices in the `dim` operation.
Rather than an attribute, the index is now an operand of type `index`.
This allows to apply the operation to dynamically ranked tensors.
The correct lowering of dynamic indices remains to be implemented.

Differential Revision: https://reviews.llvm.org/D81551
2020-06-10 13:54:47 +00:00
Mehdi Amini
d31c9e5a46 Change filecheck default to dump input on failure
Having the input dumped on failure seems like a better
default: I debugged FileCheck tests for a while without knowing
about this option, which really helps to understand failures.

Remove `-dump-input-on-failure` and the environment variable
FILECHECK_DUMP_INPUT_ON_FAILURE which are now obsolete.

Differential Revision: https://reviews.llvm.org/D81422
2020-06-09 18:57:46 +00:00
Alex Zinenko
60f443bb3b [mlir] Change dialect namespace loop->scf
All ops of the SCF dialect now use the `scf.` prefix instead of `loop.`. This
is a part of dialect renaming.

Differential Revision: https://reviews.llvm.org/D79844
2020-05-13 19:20:21 +02:00
Alex Zinenko
c25b20c0f6 [mlir] NFC: Rename LoopOps dialect to SCF (Structured Control Flow)
This dialect contains various structured control flow operaitons, not only
loops, reflect this in the name. Drop the Ops suffix for consistency with other
dialects.

Note that this only moves the files and changes the C++ namespace from 'loop'
to 'scf'. The visible IR prefix remains the same and will be updated
separately. The conversions will also be updated separately.

Differential Revision: https://reviews.llvm.org/D79578
2020-05-11 15:04:27 +02:00