247 Commits

Author SHA1 Message Date
River Riddle
1b97cdf885 [mlir][IR][NFC] Move context/location parameters of builtin Type::get methods to the start of the parameter list
This better matches the rest of the infrastructure, is much simpler, and makes it easier to move these types to being declaratively specified.

Differential Revision: https://reviews.llvm.org/D93432
2020-12-17 13:01:36 -08:00
Lei Zhang
0117865412 [mlir][spirv] NFC: Shuffle code around to better follow convention
This commit shuffles SPIR-V code around to better follow MLIR
convention. Specifically,

* Created IR/, Transforms/, Linking/, and Utils/ subdirectories and
  moved suitable code inside.
* Created SPIRVEnums.{h|cpp} for SPIR-V C/C++ enums generated from
  SPIR-V spec. Previously they are cluttered inside SPIRVTypes.{h|cpp}.
* Fixed include guards in various header files (both .h and .td).
* Moved serialization tests under test/Target/SPIRV.
* Renamed TableGen backend -gen-spirv-op-utils into -gen-spirv-attr-utils
  as it is only generating utility functions for attributes.

Reviewed By: mravishankar

Differential Revision: https://reviews.llvm.org/D93407
2020-12-17 11:03:26 -05:00
River Riddle
d7eba20052 [mlir][Inliner] Refactor the inliner to use nested pass pipelines instead of just canonicalization
Now that passes have support for running nested pipelines, the inliner can now allow for users to provide proper nested pipelines to use for optimization during inlining. This revision also changes the behavior of optimization during inlining to optimize before attempting to inline, which should lead to a more accurate cost model and prevents the need for users to schedule additional duplicate cleanup passes before/after the inliner that would already be run during inlining.

Differential Revision: https://reviews.llvm.org/D91211
2020-12-14 18:09:47 -08:00
Christian Sigg
1ffc1aaa09 [mlir] Use mlir::OpState::operator->() to get to methods of mlir::Operation.
This is a preparation step to remove those methods from OpState.

Reviewed By: mehdi_amini

Differential Revision: https://reviews.llvm.org/D93098
2020-12-13 09:58:16 +01:00
Christian Sigg
0bf4a82a5a [mlir] Use mlir::OpState::operator->() to get to methods of mlir::Operation. This is a preparation step to remove the corresponding methods from OpState.
Reviewed By: silvas, rriddle

Differential Revision: https://reviews.llvm.org/D92878
2020-12-09 12:11:32 +01:00
Thomas Raoux
3e3e276d22 [mlir][vector][NFC] Change UnrollVectorPattern to not be statically dependent on an op type
Make UnrollVectorPattern inherit from RewritePattern instead of
OpRewritePattern so that we don't need to create many patterns when applying to
many different type of ops. Since we may want to apply the pattern to all
arithmetic op, it is more convenient to filter dynamically.

Differential Revision: https://reviews.llvm.org/D92635
2020-12-04 09:53:01 -08:00
Nicolas Vasilache
a1cd559ce5 [mlir][Linalg] Properly use distribution options.
Let tiling to scf.for actually use the distribution method.
For now only Cyclic is supported.

Differential Revision: https://reviews.llvm.org/D92653
2020-12-04 14:00:54 +00:00
River Riddle
09f7a55fad [mlir][Types][NFC] Move all of the builtin Type classes to BuiltinTypes.h
This is part of a larger refactoring the better congregates the builtin structures under the BuiltinDialect. This also removes the problematic "standard" naming that clashes with the "standard" dialect, which is not defined within IR/. A temporary forward is placed in StandardTypes.h to allow time for downstream users to replaced references.

Differential Revision: https://reviews.llvm.org/D92435
2020-12-03 18:02:10 -08:00
Thomas Raoux
c503dc1b8a [mlir][linalg] Add vectorization for element-wise linalg ops
Add support for vectorization for linalg.generic representing element-wise ops.
Those are converted to transfer_read + vector ops + transfer_write.
Also re-organize the vectorization tests to be together.

Implementation derived from the work of @burmako, @agrue and
@fedelebron.

Differential Revision: https://reviews.llvm.org/D92540
2020-12-03 15:31:13 -08:00
Christian Sigg
c4a0405902 Add Operation* OpState::operator->() to provide more convenient access to members of Operation.
Given that OpState already implicit converts to Operator*, this seems reasonable.

The alternative would be to add more functions to OpState which forward to Operation.

Reviewed By: rriddle, ftynse

Differential Revision: https://reviews.llvm.org/D92266
2020-12-02 15:46:20 +01:00
River Riddle
abfd1a8b3b [mlir][PDL] Add support for PDL bytecode and expose PDL support to OwningRewritePatternList
PDL patterns are now supported via a new `PDLPatternModule` class. This class contains a ModuleOp with the pdl::PatternOp operations representing the patterns, as well as a collection of registered C++ functions for native constraints/creations/rewrites/etc. that may be invoked via the pdl patterns. Instances of this class are added to an OwningRewritePatternList in the same fashion as C++ RewritePatterns, i.e. via the `insert` method.

The PDL bytecode is an in-memory representation of the PDL interpreter dialect that can be efficiently interpreted/executed. The representation of the bytecode boils down to a code array(for opcodes/memory locations/etc) and a memory buffer(for storing attributes/operations/values/any other data necessary). The bytecode operations are effectively a 1-1 mapping to the PDLInterp dialect operations, with a few exceptions in cases where the in-memory representation of the bytecode can be more efficient than the MLIR representation. For example, a generic `AreEqual` bytecode op can be used to represent AreEqualOp, CheckAttributeOp, and CheckTypeOp.

The execution of the bytecode is split into two phases: matching and rewriting. When matching, all of the matched patterns are collected to avoid the overhead of re-running parts of the matcher. These matched patterns are then considered alongside the native C++ patterns, which rewrite immediately in-place via `RewritePattern::matchAndRewrite`,  for the given root operation. When a PDL pattern is matched and has the highest benefit, it is passed back to the bytecode to execute its rewriter.

Differential Revision: https://reviews.llvm.org/D89107
2020-12-01 15:05:50 -08:00
Christian Sigg
acb69f3b7c [mlir] Change ConvertOpToLLVMPattern::matchAndRewrite argument to concrete operand type.
Reviewed By: herhut, ftynse

Differential Revision: https://reviews.llvm.org/D92111
2020-11-28 13:09:25 +01:00
Aart Bik
d5f0d0c0c4 [mlir][sparse] add ability to select pointer/index storage type
This change gives sparse compiler clients more control over selecting
individual types for the pointers and indices in the sparse storage schemes.
Narrower width obviously results in smaller memory footprints, but the
range should always suffice for the maximum number of entries or index value.

Reviewed By: penpornk

Differential Revision: https://reviews.llvm.org/D92126
2020-11-25 17:32:44 -08:00
Aart Bik
5c4e397e6c [mlir][sparse] add parallelization strategies to sparse compiler
This CL adds the ability to request different parallelization strategies
for the generate code. Every "parallel" loop is a candidate, and converted
to a parallel op if it is an actual for-loop (not a while) and the strategy
allows dense/sparse outer/inner parallelization.

This will connect directly with the work of @ezhulenev on parallel loops.

Still TBD: vectorization strategy

Reviewed By: penpornk

Differential Revision: https://reviews.llvm.org/D91978
2020-11-24 17:17:13 -08:00
MaheshRavishankar
e65a5e5b00 [mlir][Linalg] Fuse sequence of Linalg operation (on buffers)
Enhance the tile+fuse logic to allow fusing a sequence of operations.

Make sure the value used to obtain tile shape is a
SubViewOp/SubTensorOp. Current logic used to get the bounds of loop
depends on the use of `getOrCreateRange` method on `SubViewOp` and
`SubTensorOp`. Make sure that the value/dim used to compute the range
is from such ops.  This fix is a reasonable WAR, but a btter fix would
be to make `getOrCreateRange` method be a method of `ViewInterface`.

Differential Revision: https://reviews.llvm.org/D90991
2020-11-23 10:30:51 -08:00
Thomas Raoux
369c51a74b [mlir][vector] Add transfer_op LoadToStore forwarding and deadStore optimizations
Add transformation to be able to forward transfer_write into transfer_read
operation and to be able to remove dead transfer_write when a transfer_write is
overwritten before being read.

Differential Revision: https://reviews.llvm.org/D91321
2020-11-20 11:59:01 -08:00
Mikhail Goncharov
0caa82e2ac Revert "[mlir][Linalg] Fuse sequence of Linalg operation (on buffers)"
This reverts commit f8284d21a8e294d58a0acd4b8b2e906d7a9f110c.

Revert "[mlir][Linalg] NFC: Expose some utility functions used for promotion."

This reverts commit 0c59f51592ef5c014352994369f5216c6376fae1.

Revert "Remove unused isZero function"

This reverts commit 0f9f0a4046e11c2b4c130640f343e3b2b5db08c1.

Change f8284d21 led to multiple failures in IREE compilation.
2020-11-20 13:12:54 +01:00
MaheshRavishankar
f8284d21a8 [mlir][Linalg] Fuse sequence of Linalg operation (on buffers)
Enhance the tile+fuse logic to allow fusing a sequence of operations.

Differential Revision: https://reviews.llvm.org/D90991
2020-11-19 19:03:06 -08:00
River Riddle
65fcddff24 [mlir][BuiltinDialect] Resolve comments from D91571
* Move ops to a BuiltinOps.h
* Add file comments
2020-11-19 11:12:49 -08:00
Diego Caballero
c1ba9c43ad [mlir][Affine] Refactor affine fusion code in pass to utilities
Refactoring/clean-up step needed to add support for producer-consumer fusion
with multi-store producer loops and, in general, to implement more general
loop fusion strategies in Affine. It introduces the following changes:
  - AffineLoopFusion pass now uses loop fusion utilities more broadly to compute
    fusion legality (canFuseLoops utility) and perform the fusion transformation
    (fuseLoops utility).
  - Loop fusion utilities have been extended to deal with AffineLoopFusion
    requirements and assumptions while preserving both loop fusion utilities and
    AffineLoopFusion current functionality within a unified implementation.
    'FusionStrategy' has been introduced for this purpose and, in the future, it
    will allow us to have a single loop fusion core implementation that will produce
    different fusion outputs depending on the strategy used.
  - Improve separation of concerns for legality and profitability analysis:
    'isFusionProfitable' no longer filters out illegal scenarios that 'canFuse'
    didn't detect, or the other way around. 'canFuse' now takes loop dependences
    into account to determine the fusion loop depth (producer-consumer fusion only).
  - As a result, maximal fusion now doesn't require any profitability analysis.
  - Slices are now computed only once and reused across the legality, profitability
    and fusion transformation steps (producer-consumer).
  - Refactor some utilities and remove redundant copies of them.

This patch is NFCI and should preserve the existing functionality of both the
AffineLoopFusion pass and the affine fusion utilities.

Reviewed By: andydavis1, bondhugula

Differential Revision: https://reviews.llvm.org/D90798
2020-11-18 13:50:32 -08:00
Aart Bik
eced4a8e6f [mlir] [sparse] start of sparse tensor compiler support
As discussed in https://llvm.discourse.group/t/mlir-support-for-sparse-tensors/2020
this CL is the start of sparse tensor compiler support in MLIR. Starting with a
"dense" kernel expressed in the Linalg dialect together with per-dimension
sparsity annotations on the tensors, the compiler automatically lowers the
kernel to sparse code using the methods described in Fredrik Kjolstad's thesis.

Many details are still TBD. For example, the sparse "bufferization" is purely
done locally since we don't have a global solution for propagating sparsity
yet. Furthermore, code to input and output the sparse tensors is missing.
Nevertheless, with some hand modifications, the generated MLIR can be
easily converted into runnable code already.

Reviewed By: nicolasvasilache, ftynse

Differential Revision: https://reviews.llvm.org/D90994
2020-11-17 13:10:42 -08:00
River Riddle
73ca690df8 [mlir][NFC] Remove references to Module.h and Function.h
These includes have been deprecated in favor of BuiltinDialect.h, which contains the definitions of ModuleOp and FuncOp.

Differential Revision: https://reviews.llvm.org/D91572
2020-11-17 00:55:47 -08:00
Sean Silva
7c62c6313b [mlir] Add DecomposeCallGraphTypes pass.
This replaces the old type decomposition logic that was previously mixed
into bufferization, and makes it easily accessible.

This also deletes TestFinalizingBufferize, because after we remove the type
decomposition, it doesn't do anything that is not already provided by
func-bufferize.

Differential Revision: https://reviews.llvm.org/D90899
2020-11-16 12:25:35 -08:00
Nicolas Vasilache
7625742237 [mlir][Linalg] Add support for tileAndDistribute on tensors.
scf.parallel is currently not a good fit for tiling on tensors.
Instead provide a path to parallelism directly through scf.for.
For now, this transformation ignores the distribution scheme and always does a block-cyclic mapping (where block is the tile size).

Differential revision: https://reviews.llvm.org/D90475
2020-11-16 11:12:50 +00:00
Thomas Raoux
6ad31c0f4a [mlir][vector] Support N-D vector in InsertMap/ExtractMap op
Support multi-dimension vector for InsertMap/ExtractMap op and update the
transformations. Currently the relation between IDs and dimension is implicitly
deduced from the types. We can then calculate an AffineMap based on it. In the
future the AffineMap could be part of the operation itself.

Differential Revision: https://reviews.llvm.org/D90995
2020-11-13 12:40:17 -08:00
MaheshRavishankar
bf3861bf71 [mlir][Linalg] Change LinalgDependenceGraph to use LinalgOp.
Using LinalgOp will reduce the repeated conversion from Operation <->
LinalgOp.

Differential Revision: https://reviews.llvm.org/D91101
2020-11-13 12:34:38 -08:00
MaheshRavishankar
5ca20851e4 [mlir][Linalg] Improve the logic to perform tile and fuse with better dependence tracking.
This change does two main things
1) An operation might have multiple dependences to the same
   producer. Not tracking them correctly can result in incorrect code
   generation with fusion. To rectify this the dependence tracking
   needs to also have the operand number in the consumer.
2) Improve the logic used to find the fused loops making it easier to
   follow. The only constraint for fusion is that linalg ops (on
   buffers) have update semantics for the result. Fusion should be
   such that only one iteration of the fused loop (which is also a
   tiled loop) must touch only one (disjoint) tile of the output. This
   could be relaxed by allowing for recomputation that is the default
   when oeprands are tensors, or can be made legal with promotion of
   the fused view (in future).

Differential Revision: https://reviews.llvm.org/D90579
2020-11-12 00:25:24 -08:00
Thomas Raoux
023f2400f2 [mlir] Fix post-dominance between blocks of different regions.
If block A and B are in different regions and region of A is not an ancestor of
B, either A is included in region of B or the two regions are disjoint. In both
case A doesn't post-dominate B.

Differential Revision: https://reviews.llvm.org/D91225
2020-11-11 11:20:53 -08:00
Eugene Zhulenev
bb0d5f767d [mlir] Add NumberOfExecutions analysis + update RegionBranchOpInterface interface to query number of region invocations
Implements RFC discussed in: https://llvm.discourse.group/t/rfc-operationinstancesinterface-or-any-better-name/2158/10

Reviewed By: silvas, ftynse, rriddle

Differential Revision: https://reviews.llvm.org/D90922
2020-11-11 01:43:17 -08:00
Alexander Belyaev
9d02e0e38d [mlir][std] Add ExpandOps pass.
The pass combines patterns of ExpandAtomic, ExpandMemRefReshape,
StdExpandDivs passes. The pass is meant to legalize STD for conversion to LLVM.

Differential Revision: https://reviews.llvm.org/D91082
2020-11-09 21:58:28 +01:00
Sean Silva
f7bc568266 [mlir] Remove AppendToArgumentsList functionality from BufferizeTypeConverter.
This functionality is superceded by BufferResultsToOutParams pass (see
https://reviews.llvm.org/D90071) for users the require buffers to be
out-params. That pass should be run immediately after all tensors are gone from
the program (before buffer optimizations and deallocation insertion), such as
immediately after a "finalizing" bufferize pass.

The -test-finalizing-bufferize pass now defaults to what used to be the
`allowMemrefFunctionResults=true` flag. and the
finalizing-bufferize-allowed-memref-results.mlir file is moved
to test/Transforms/finalizing-bufferize.mlir.

Differential Revision: https://reviews.llvm.org/D90778
2020-11-05 11:20:09 -08:00
Alexander Belyaev
72c65b698e [mlir] Move TestDialect and its passes to mlir::test namespace.
TestDialect has many operations and they all live in ::mlir namespace.
Sometimes it is not clear whether the ops used in the code for the test passes
belong to Standard or to Test dialects.

Also, with this change it is easier to understand what test passes registered
in mlir-opt are actually passes in mlir/test.

Differential Revision: https://reviews.llvm.org/D90794
2020-11-05 15:29:15 +01:00
Alexander Bosch
5452fa6a59 [MLIR] Added test operations to replace linalg dependency for
BufferizeTests.

Summary:
Added test operations to replace the LinalgDialect dependency in tests
which use the buffer-deallocation, buffer-hoisting,
buffer-loop-hoisting, promote-buffers-to-stack,
buffer-placement-preparation-allowed-memref-resutls and
buffer-placement-preparation pass. Adapted the corresponding tests cases
and TestBufferPlacement.cpp.

Differential Revision: https://reviews.llvm.org/D90037
2020-11-03 12:18:49 +01:00
Mehdi Amini
008b9d97cb Make the implicit nesting behavior of the PassManager user-controllable and default to false
This is an error prone behavior, I frequently have ~20 min debugging sessions when I hit
an unexpected implicit nesting. This default makes the C++ API safer for users.

Depends On D90669

Reviewed By: rriddle

Differential Revision: https://reviews.llvm.org/D90671
2020-11-03 11:17:44 +00:00
Mehdi Amini
cd7107a62b Handle the verifier at run() time in the PassManager instead of build time
This simplifies a few parts of the pass manager, but in particular we don't add as many
verifierpass as there are passes in the pipeline, and we can now enable/disable the
verifier after the fact on an already built PassManager.

Reviewed By: rriddle

Differential Revision: https://reviews.llvm.org/D90669
2020-11-03 11:17:14 +00:00
Sean Silva
773ad135a3 [mlir][Bufferize] Rename TestBufferPlacement to TestFinalizingBufferize
BufferPlacement is no longer part of bufferization. However, this test
is an important test of "finalizing" bufferize passes.
A "finalizing" bufferize conversion is one that performs a "full"
conversion and expects all tensors to be gone from the program. This in
particular involves rewriting funcs (including block arguments of the
contained region), calls, and returns. The unique property of finalizing
bufferization passes is that they cannot be done via a local
transformation with suitable materializations to ensure composability
(as other bufferization passes do). For example, if a call is
rewritten, the callee needs to be rewritten otherwise the IR will end up
invalid. Thus, finalizing bufferization passes require an atomic change
to the entire program (e.g. the whole module).

This new designation makes it clear also that it shouldn't be testing
bufferization of linalg ops, so the tests have been updated to not use
linalg.generic ops. (linalg.copy is still used as the "copy" op for
copying into out-params)

Differential Revision: https://reviews.llvm.org/D89979
2020-11-02 12:42:32 -08:00
Thomas Raoux
5d45f758f0 [mlir][vector] Improve vector distribute integration test and fix block distribution
Fix semantic in the distribute integration test based on offline feedback. This
exposed a bug in block distribution, we need to make sure the id is multiplied
by the stride of the vector. Fix the transformation and unit test.

Differential Revision: https://reviews.llvm.org/D89291
2020-10-29 14:54:53 -07:00
Nicolas Vasilache
9b17bf2e54 [mlir][Linalg] Make Linalg fusion a test pass
Linalg "tile-and-fuse" is currently exposed as a Linalg pass "-linalg-fusion" but only the mechanics of the transformation are currently relevant.
Instead turn it into a "-test-linalg-greedy-fusion" pass which performs canonicalizations to enable more fusions to compose.
This allows dropping the OperationFolder which is not meant to be used with the pattern rewrite infrastructure.

Differential Revision: https://reviews.llvm.org/D90394
2020-10-29 15:18:51 +00:00
Alexander Belyaev
7a996027b9 [mlir] Convert memref_reshape to memref_reinterpret_cast.
Differential Revision: https://reviews.llvm.org/D90235
2020-10-28 21:15:32 +01:00
River Riddle
3fffffa882 [mlir][Pattern] Add a new FrozenRewritePatternList class
This class represents a rewrite pattern list that has been frozen, and thus immutable. This replaces the uses of OwningRewritePatternList in pattern driver related API, such as dialect conversion. When PDL becomes more prevalent, this API will allow for optimizing a set of patterns once without the need to do this per run of a pass.

Differential Revision: https://reviews.llvm.org/D89104
2020-10-26 18:01:06 -07:00
River Riddle
b6eb26fd0e [mlir][NFC] Move around the code related to PatternRewriting to improve layering
There are several pieces of pattern rewriting infra in IR/ that really shouldn't be there. This revision moves those pieces to a better location such that they are easier to evolve in the future(e.g. with PDL). More concretely this revision does the following:

* Create a Transforms/GreedyPatternRewriteDriver.h and move the apply*andFold methods there.
The definitions for these methods are already in Transforms/ so it doesn't make sense for the declarations to be in IR.

* Create a new lib/Rewrite library and move PatternApplicator there.
This new library will be focused on applying rewrites, and will also include compiling rewrites with PDL.

Differential Revision: https://reviews.llvm.org/D89103
2020-10-26 18:01:06 -07:00
Thomas Raoux
bd07be4f3f [mlir][vector] Update doc strings for insert_map/extract_map and fix insert_map semantic
Based on discourse discussion, fix the doc string and remove examples with
wrong semantic. Also fix insert_map semantic by adding missing operand for
vector we are inserting into.

Differential Revision: https://reviews.llvm.org/D89563
2020-10-26 10:47:01 -07:00
MaheshRavishankar
b6204b995e [mlir][Vector] Introduce UnrollVectorOptions to control vector unrolling.
The current pattern for vector unrolling takes the native shape to
unroll to at pattern instantiation time, but the native shape might
defer based on the types of the operand. Introduce a
UnrollVectorOptions struct which allows for using a function that will
return the native shape based on the operation. Move other options of
unrolling like `filterConstraints` into this struct.

Differential Revision: https://reviews.llvm.org/D89744
2020-10-23 13:52:26 -07:00
Christian Sigg
ad3ecc24b1 [mlir][gpu] NFC: Make room for more than one GPU rewrite pattern.
AllReduceLowering is currently the only GPU rewrite pattern, but more are coming. This is a preparation change.

Reviewed By: herhut

Differential Revision: https://reviews.llvm.org/D89370
2020-10-19 07:52:47 +02:00
Thomas Raoux
edbdea7466 [mlir][vector] Add unrolling patterns for Transfer read/write
Adding unroll support for transfer read and transfer write operation. This
allows to pick the ideal size for the memory access for a given target.

Differential Revision: https://reviews.llvm.org/D89289
2020-10-15 15:17:36 -07:00
Sean Silva
9a14cb53cb [mlir][bufferize] Rename BufferAssignment* to Bufferize*
Part of the refactor discussed in:
https://llvm.discourse.group/t/what-is-the-strategy-for-tensor-memref-conversion-bufferization/1938/17

Differential Revision: https://reviews.llvm.org/D89271
2020-10-14 12:39:16 -07:00
Nicolas Vasilache
af5be38a01 [mlir][Linalg] Make a Linalg CodegenStrategy available.
This revision adds a programmable codegen strategy from linalg based on staged rewrite patterns. Testing is exercised on a simple linalg.matmul op.

Differential Revision: https://reviews.llvm.org/D89374
2020-10-14 11:11:26 +00:00
Nicolas Vasilache
422aaf31da [mlir][Linalg] Add named Linalg ops on tensor to buffer support.
This revision introduces support for buffer allocation for any named linalg op.
To avoid template instantiating many ops, a new ConversionPattern is created to capture the LinalgOp interface.

Some APIs are updated to remain consistent with MLIR style:
`OwningRewritePatternList * -> OwningRewritePatternList &`
`BufferAssignmentTypeConverter * -> BufferAssignmentTypeConverter &`

Differential revision: https://reviews.llvm.org/D89226
2020-10-12 11:20:23 +00:00
Sean Silva
a2b6c75ac0 [mlir] Rename BufferPlacement.h to Bufferize.h
Context: https://llvm.discourse.group/t/what-is-the-strategy-for-tensor-memref-conversion-bufferization/1938/14

Differential Revision: https://reviews.llvm.org/D89174
2020-10-09 17:48:20 -07:00
Thomas Raoux
cf402a1987 [mlir][vector] Add unit test for vector distribute by block
When distributing a vector larger than the given multiplicity, we can
distribute it by block where each id gets a chunk of consecutive element
along the dimension distributed. This adds a test for this case and adds extra
checks to make sure we don't distribute for cases not multiple of multiplicity.

Differential Revision: https://reviews.llvm.org/D89061
2020-10-08 14:44:03 -07:00