Unroll-and-jam currently doesn't work when the loop being unroll-and-jammed
or any of its inner loops has iter_args. This patch modifies the
unroll-and-jam utility to support loops with iter_args.
Reviewed By: bondhugula
Differential Revision: https://reviews.llvm.org/D110085
When we vectorize a scalar constant, the vector constant is inserted before its
first user if the scalar constant is defined outside the loops to be vectorized.
It is possible that the vector constant does not dominate all its users. To fix
the problem, we find the innermost vectorized loop that encloses that first user
and insert the vector constant at the top of the loop body.
Reviewed By: nicolasvasilache
Differential Revision: https://reviews.llvm.org/D106609
Historically the builtin dialect has had an empty namespace. This has unfortunately created a very awkward situation, where many utilities either have to special case the empty namespace, or just don't work at all right now. This revision adds a namespace to the builtin dialect, and starts to cleanup some of the utilities to no longer handle empty namespaces. For now, the assembly form of builtin operations does not require the `builtin.` prefix. (This should likely be re-evaluated though)
Differential Revision: https://reviews.llvm.org/D105149
Fix affine.for empty loop body folder in the presence of yield values.
The existing pattern ignored iter_args/yield values and thus crashed
when yield values had uses.
Reviewed By: mehdi_amini
Differential Revision: https://reviews.llvm.org/D106121
AffineForOp's folding hook is expected to fold away trivially empty
affine.for. This allows simplification to happen as part of the
canonicalizer and from wherever the folding hook is used. While more
complex analysis based zero trip count detection is available from other
passes in analysis and transforms, simple and inexpensive folding had
been missing.
Also, update/improve affine.for op documentation clarifying semantics of
the result values for zero trip count loops.
Differential Revision: https://reviews.llvm.org/D106123
Introduce a new rewrite driver (MultiOpPatternRewriteDriver) to rewrite
a supplied list of ops and other ops. Provide a knob to restrict
rewrites strictly to those ops or also to affected ops (but still not to
completely related ops).
This rewrite driver is commonly needed to run any simplification and
cleanup at the end of a transforms pass or transforms utility in a way
that only simplifies relevant IR. This makes it easy to write test cases
while not performing unrelated whole IR simplification that may
invalidate other state at the caller.
The introduced utility provides more freedom to developers of transforms
and transform utilities to perform focussed and local simplification. In
several cases, it provides greater efficiency as well as more
simplification when compared to repeatedly calling
`applyOpPatternsAndFold`; in other cases, it avoids the need to
undesirably call `applyPatternsAndFoldGreedily` to do unrelated
simplification in a FuncOp.
Update a few transformations that were earlier using
applyOpPatternsAndFold (SimplifyAffineStructures,
affineDataCopyGenerate, a linalg transform).
TODO:
- OpPatternRewriteDriver can be removed as it's a special case of
MultiOpPatternRewriteDriver, i.e., both can be merged.
Differential Revision: https://reviews.llvm.org/D106232
When an affine.if operation is returning/yielding results and has a
trivially true or false condition, then its 'then' or 'else' block,
respectively, is promoted to the affine.if's parent block and then, the
affine.if operation is replaced by the correct results/yield values.
Relevant test cases are also added.
Signed-off-by: Srishti Srivastava <srishti.srivastava@polymagelabs.com>
Differential Revision: https://reviews.llvm.org/D105418
Fix FlatAffineConstraints::getConstantBoundOnDimSize to ensure that
returned bounds on dim size are always non-negative regardless of the
constraints on that dimension. Add an assertion at the user.
Differential Revision: https://reviews.llvm.org/D105171
Affine scalar replacement (and other affine passes, though not fixed here) don't properly handle operations with nested regions. This patch fixes the pass and two affine utilities to function properly given a non-affine internal region
This patch prevents the pass from throwing an internal compiler error when running on the added test case.
Differential Revision: https://reviews.llvm.org/D105058
Deduce circumstances where an affine load could not possibly be read by an operation (such as an affine load), and if so, eliminate the load
Differential Revision: https://reviews.llvm.org/D105041
Fix generateCopyForMemRefRegion for a missing check: in some cases, when
the thing to generate copies for itself is empty, no fast buffer/copy
loops would have been allocated/generated. Add an extra assertion there
while at this.
Differential Revision: https://reviews.llvm.org/D105170
MemRefDataFlow performs mem2reg style operations for affine load/stores. Unfortunately, it is not presently correct in the presence of external operations such as memref.cast, or function calls. This diff extends the functionality of the pass to remain correct in the presence of such ops.
Differential Revision: https://reviews.llvm.org/D104053
This revision refactors the usage of multithreaded utilities in MLIR to use a common
thread pool within the MLIR context, in addition to a new utility that makes writing
multi-threaded code in MLIR less error prone. Using a unified thread pool brings about
several advantages:
* Better thread usage and more control
We currently use the static llvm threading utilities, which do not allow multiple
levels of asynchronous scheduling (even if there are open threads). This is due to
how the current TaskGroup structure works, which only allows one truly multithreaded
instance at a time. By having our own ThreadPool we gain more control and flexibility
over our job/thread scheduling, and in a followup can enable threading more parts of
the compiler.
* The static nature of TaskGroup causes issues in certain configurations
Due to the static nature of TaskGroup, there have been quite a few problems related to
destruction that have caused several downstream projects to disable threading. See
D104207 for discussion on some related fallout. By having a ThreadPool scoped to
the context, we don't have to worry about destruction and can ensure that any
additional MLIR thread usage ends when the context is destroyed.
Differential Revision: https://reviews.llvm.org/D104516
Make store to load fwd condition for -memref-dataflow-opt less
conservative. Post dominance info is not really needed. Add additional
check for common cases.
Differential Revision: https://reviews.llvm.org/D104174
To control the number of outer parallel loops, we need to process the
outer loops first and hence pre-order walk fixes the issue.
Reviewed By: bondhugula
Differential Revision: https://reviews.llvm.org/D104361
The commit simplifies affine.if ops :
The affine if operation gets removed if the condition is universally true or false and then/else block is merged with the parent block.
Signed-off-by: Shashij Gupta shashij.gupta@polymagelabs.com
Reviewed By: bondhugula, pr4tgpt
Differential Revision: https://reviews.llvm.org/D104015
Currently canonicalizations of a store and a cast try to fold all casts into the store.
In the case where the operand being stored is itself a cast, this is illegal as the type of the value being stored
will change. This PR fixes this by not checking the value for folding with a cast.
Depends on https://reviews.llvm.org/D103828
Differential Revision: https://reviews.llvm.org/D103829
Allow support for specifying empty IVs in an `affine.parallel`.
For example:
```
affine.parallel () = () to () {
affine.yield
}
```
Reviewed By: bondhugula, jbruestle
Differential Revision: https://reviews.llvm.org/D102895
This provides a sizable compile time improvement by seeding
the worklist in an order that leads to less iterations of the
worklist.
This patch only changes the behavior of the Canonicalize pass
itself, it does not affect other passes that use the
GreedyPatternRewrite driver
Differential Revision: https://reviews.llvm.org/D103053
Prevent users of `iter_args` of an affine for loop from being hoisted
out of it. Otherwise, LICM leads to a violation of the SSA dominance
(as demonstrated in the added test case).
Fixes: https://bugs.llvm.org/show_bug.cgi?id=50103
Reviewed By: bondhugula, ayzhuang
Differential Revision: https://reviews.llvm.org/D102984
This patch adds support for vectorizing loops with 'iter_args'
implementing known reductions along the vector dimension. Comparing to
the non-vector-dimension case, two additional things are done during
vectorization of such loops:
- The resulting vector returned from the loop is reduced to a scalar
using `vector.reduce`.
- In some cases a mask is applied to the vector yielded at the end of
the loop to prevent garbage values from being written to the
accumulator.
Vectorization of reduction loops is disabled by default. To enable it, a
map from loops to array of reduction descriptors should be explicitly passed to
`vectorizeAffineLoops`, or `vectorize-reductions=true` should be passed
to the SuperVectorize pass.
Current limitations:
- Loops with a non-unit step size are not supported.
- n-D vectorization with n > 1 is not supported.
Reviewed By: nicolasvasilache
Differential Revision: https://reviews.llvm.org/D100694
Added canonicalization for vector_load and vector_store. An existing
pattern SimplifyAffineOp can be reused to compose maps that supplies
result into them. Added AffineVectorStoreOp and AffineVectorLoadOp
into static_assert of SimplifyAffineOp to allow operation to use it.
This fixes the bug filed: https://bugs.llvm.org/show_bug.cgi?id=50058
Reviewed By: bondhugula
Differential Revision: https://reviews.llvm.org/D101691
This enables to express more complex parallel loops in the affine framework,
for example, in cases of tiling by sizes not dividing loop trip counts perfectly
or inner wavefront parallelism, among others. One can't use affine.max/min
and supply values to the nested loop bounds since the results of such
affine.max/min operations aren't valid symbols. Making them valid symbols
isn't an option since they would introduce selection trees into memref
subscript arithmetic as an unintended and undesired consequence. Also
add support for converting such loops to SCF. Drop some API that isn't used in
the core repo from AffineParallelOp since its semantics becomes ambiguous in
presence of max/min bounds. Loop normalization is currently unavailable for
such loops.
Depends On D101171
Reviewed By: bondhugula
Differential Revision: https://reviews.llvm.org/D101172
Introduce a basic support for parallelizing affine loops with reductions
expressed using iteration arguments. Affine parallelism detector now has a flag
to assume such reductions are parallel. The transformation handles a subset of
parallel reductions that are can be expressed using affine.parallel:
integer/float addition and multiplication. This requires to detect the
reduction operation since affine.parallel only supports a fixed set of
reduction operators.
Reviewed By: chelini, kumasento, bondhugula
Differential Revision: https://reviews.llvm.org/D101171
This patch collects operations that have users in a for loop and uses
them when loop invariant operations are detected and hoisted.
Reviewed By: bondhugula, vinayaka-polymage
Differential Revision: https://reviews.llvm.org/D99761
This reverts commit 361b7d125b by Chris
Lattner <clattner@nondot.org> dated Fri Mar 19 21:22:15 2021 -0700.
The change to the greedy rewriter driver picking a different order was
made without adequate analysis of the trade-offs and experimentation. A
change like this has far reaching consequences on transformation
pipelines, and a major impact upstream and downstream. For eg., one
can’t be sure that it doesn’t slow down a large number of cases by small
amounts or create other issues. More discussion here:
https://llvm.discourse.group/t/speeding-up-canonicalize/3015/25
Reverting this so that improvements to the traversal order can be made
on a clean slate, in bigger steps, and higher bar.
Differential Revision: https://reviews.llvm.org/D99329
This identifies a pattern where the producer affine min/max op
is bound to a dimension/symbol that is used as a standalone
expression in the consumer affine op's map. In that case the
producer affine min/max op can be merged into its consumer.
For example, a pattern like the following:
```
%0 = affine.min affine_map<()[s0] -> (s0 + 16, s0 * 8)> ()[%sym1]
%1 = affine.min affine_map<(d0)[s0] -> (s0 + 4, d0)> (%0)[%sym2]
```
Can be turned into:
```
%1 = affine.min affine_map<
()[s0, s1] -> (s0 + 4, s1 + 16, s1 * 8)> ()[%sym2, %sym1]
```
Differential Revision: https://reviews.llvm.org/D99016
If there are multiple identical expressions in an affine
min/max op's map, we can just keep one.
Differential Revision: https://reviews.llvm.org/D99015
This reapplies b5d9a3c / https://reviews.llvm.org/D98609 with a one line fix in
processExistingConstants to skip() when erasing a constant we've already seen.
Original commit message:
1) Change the canonicalizer to walk the function in top-down order instead of
bottom-up order. This composes well with the "top down" nature of constant
folding and simplification, reducing iterations and re-evaluation of ops in
simple cases.
2) Explicitly enter existing constants into the OperationFolder table before
canonicalizing. Previously we would "constant fold" them and rematerialize
them, wastefully recreating a bunch fo constants, which lead to pointless
memory traffic.
Both changes together provide a 33% speedup for canonicalize on some mid-size
CIRCT examples.
One artifact of this change is that the constants generated in normal pattern
application get inserted at the top of the function as the patterns are applied.
Because of this, we get "inverted" constants more often, which is an aethetic
change to the IR but does permute some testcases.
Differential Revision: https://reviews.llvm.org/D99006
This reverts commit b5d9a3c923.
The commit introduced a memory error in canonicalization/operation
walking that is exposed when compiled with ASAN. It leads to crashes in
some "release" configurations.
Two changes:
1) Change the canonicalizer to walk the function in top-down order instead of
bottom-up order. This composes well with the "top down" nature of constant
folding and simplification, reducing iterations and re-evaluation of ops in
simple cases.
2) Explicitly enter existing constants into the OperationFolder table before
canonicalizing. Previously we would "constant fold" them and rematerialize
them, wastefully recreating a bunch fo constants, which lead to pointless
memory traffic.
Both changes together provide a 33% speedup for canonicalize on some mid-size
CIRCT examples.
One artifact of this change is that the constants generated in normal pattern
application get inserted at the top of the function as the patterns are applied.
Because of this, we get "inverted" constants more often, which is an aethetic
change to the IR but does permute some testcases.
Differential Revision: https://reviews.llvm.org/D98609
This patch adds support for vectorizing loops with 'iter_args' when those loops
are not a vector dimension. This allows vectorizing outer loops with an inner
'iter_args' loop (e.g., reductions). Vectorizing scenarios where 'iter_args'
loops are vector dimensions would require more work (e.g., analysis,
generating horizontal reduction, etc.) not included in this patch.
Reviewed By: nicolasvasilache
Differential Revision: https://reviews.llvm.org/D97892
This patch replaces the root-terminal vectorization approach implemented in the
Affine vectorizer with a topological order approach that vectorizes all the
operations within the target loop nest. These are the most important changes
introduced by the new algorithm:
* Removed tracking of root and terminal ops. Existing vectorization
functionality is preserved and extended so that loop nests without
root-terminal chains can be vectorized.
* Vectorizing a loop nest now only requires a single topological traversal.
* A new vector loop nest is incrementally built along the vectorization
process. The original scalar loop is kept intact. No cloning guard is needed
to recover the scalar loop if vectorization fails. This approach also
simplifies the challenging task of replacing a loop operation amid the
vectorization process without invalidating the analysis information that
depends on the original loop.
* Vectorization of specific operations has been implemented as independent,
preparing them to be moved to a potential vectorization interface.
Reviewed By: nicolasvasilache
Differential Revision: https://reviews.llvm.org/D97442
This patch adds support for vectorizing loops with 'iter_args' when those loops
are not a vector dimension. This allows vectorizing outer loops with an inner
'iter_args' loop (e.g., reductions). Vectorizing scenarios where 'iter_args'
loops are vector dimensions would require more work (e.g., analysis,
generating horizontal reduction, etc.) not included in this patch.
Reviewed By: nicolasvasilache
Differential Revision: https://reviews.llvm.org/D97892
This patch replaces the root-terminal vectorization approach implemented in the
Affine vectorizer with a topological order approach that vectorizes all the
operations within the target loop nest. These are the most important changes
introduced by the new algorithm:
* Removed tracking of root and terminal ops. Existing vectorization
functionality is preserved and extended so that loop nests without
root-terminal chains can be vectorized.
* Vectorizing a loop nest now only requires a single topological traversal.
* A new vector loop nest is incrementally built along the vectorization
process. The original scalar loop is kept intact. No cloning guard is needed
to recover the scalar loop if vectorization fails. This approach also
simplifies the challenging task of replacing a loop operation amid the
vectorization process without invalidating the analysis information that
depends on the original loop.
* Vectorization of specific operations has been implemented as independent,
preparing them to be moved to a potential vectorization interface.
Reviewed By: nicolasvasilache
Differential Revision: https://reviews.llvm.org/D97442
Fix 'isLoopParallel' utility so that 'iter_args' is taken into account
and loops with loop-carried dependences are not classified as parallel.
Reviewed By: tungld, vinayaka-polymage
Differential Revision: https://reviews.llvm.org/D97347
The current implementation of tilePerfectlyNested utility doesn't handle
the non-unit step size. We have added support to perform tiling
correctly even if the step size of the loop to be tiled is non-unit.
Fixes https://bugs.llvm.org/show_bug.cgi?id=49188.
Differential Revision: https://reviews.llvm.org/D97037
This commit introduced a cyclic dependency:
Memref dialect depends on Standard because it used ConstantIndexOp.
Std depends on the MemRef dialect in its EDSC/Intrinsics.h
Working on a fix.
This reverts commit 8aa6c3765b.
Create the memref dialect and move several dialect-specific ops without
dependencies to other ops from std dialect to this dialect.
Moved ops:
AllocOp -> MemRef_AllocOp
AllocaOp -> MemRef_AllocaOp
DeallocOp -> MemRef_DeallocOp
MemRefCastOp -> MemRef_CastOp
GetGlobalMemRefOp -> MemRef_GetGlobalOp
GlobalMemRefOp -> MemRef_GlobalOp
PrefetchOp -> MemRef_PrefetchOp
ReshapeOp -> MemRef_ReshapeOp
StoreOp -> MemRef_StoreOp
TransposeOp -> MemRef_TransposeOp
ViewOp -> MemRef_ViewOp
The roadmap to split the memref dialect from std is discussed here:
https://llvm.discourse.group/t/rfc-split-the-memref-dialect-from-std/2667
Differential Revision: https://reviews.llvm.org/D96425