As part of this extension this change also does some general cleanup
1) Make all the methods take `RewriterBase` as arguments instead of
creating their own builders that tend to crash when used within
pattern rewrites
2) Split `coalesePerfectlyNestedLoops` into two separate methods, one
for `scf.for` and other for `affine.for`. The templatization didnt
seem to be buying much there.
Also general clean up of tests.
Adds support for fusing two scf.for loops occurring in the same block.
Uses the rudimentary checks already in place for scf.forall (like the
target loop's operands being dominated by the source loop).
- Fixes a bug in the dominance check whereby it was checked that values
in the target loop themselves dominated the source loop rather than the
ops that define these operands.
- Renames the LoopFuseSibling op to LoopFuseSiblingOp.
- Updates LoopFuseSiblingOp's description.
- Adds tests for using LoopFuseSiblingOp on scf.for loops, including one
which fails without the fix for the dominance check.
- Adds tests checking the different failure modes of the dominance
checker.
- Adds test for case whereby scf.yield is automatically generated when
there are no loop-carried variables.
I believe the semantics should be the same, but this saves 1 op and simplifies the code.
For example, the following two instructions:
```
%2 = cmp sgt %0, %1
%3 = select %2, %0, %1
```
Are equivalent to:
```
%2 = maxsi %0 %1
```
Using `LoopLikeOpInterface` as the basis for the implementation unifies
all the tiling logic for both `scf.for` and `scf.forall`. The only
difference is the actual loop generation. This is a follow up to
https://github.com/llvm/llvm-project/pull/72178
Instead of many entry points for each loop type, the loop type is now
passed as part of the options passed to the tiling method.
This is a breaking change with the following changes
1) The `scf::tileUsingSCFForOp` is renamed to `scf::tileUsingSCF`
2) The `scf::tileUsingSCFForallOp` is deprecated. The same
functionality is obtained by using `scf::tileUsingSCF` and setting
the loop type in `scf::SCFTilingOptions` passed into this method to
`scf::SCFTilingOptions::LoopType::ForallOp` (using the
`setLoopType` method).
3) The `scf::tileConsumerAndFusedProducerGreedilyUsingSCFForOp` is
renamed to `scf::tileConsumerAndFuseProducerUsingSCF`. The use of
the `controlFn` in `scf::SCFTileAndFuseOptions` allows implementing
any strategy with the default callback implemeting the greedy fusion.
4) The `scf::SCFTilingResult` and `scf::SCFTileAndFuseResult` now use
`SmallVector<LoopLikeOpInterface>`.
5) To make `scf::ForallOp` implement the parts of
`LoopLikeOpInterface` needed, the `getOutputBlockArguments()`
method is replaced with `getRegionIterArgs()`
These changes now bring the tiling and fusion capabilities using
`scf.forall` on par with what was already supported by `scf.for`
In particular, `upperBoundUnrolledCst` may be larger than `ubCst` when:
1. the step size is greater than 1;
2. `ub - lb` is not evenly divisible by the step size; and
3. the loop's trip count is evenly divisible by the unroll factor.
This is okay since the non-unit step size ensures that the unrolled loop
maintains the same trip count as the original loop. Added a test case
for this.
Fixes#61832.
Co-authored-by: Stephen Chou <stephenchou@google.com>
`affine::replaceForOpWithNewYields` and `replaceLoopWithNewYields` (for
"scf.for") are now interface methods and additional loop-carried
variables can now be added to "scf.for"/"affine.for" uniformly. (No more
`TypeSwitch` needed.)
Note: `scf.while` and other loops with loop-carried variables can
implement `replaceWithAdditionalYields`, but to keep this commit small,
that is not done in this commit.
This commit implements `LoopLikeOpInterface` on `scf.while`. This
enables LICM (and potentially other transforms) on `scf.while`.
`LoopLikeOpInterface::getLoopBody()` is renamed to `getLoopRegions` and
can now return multiple regions.
Also fix a bug in the default implementation of
`LoopLikeOpInterface::isDefinedOutsideOfLoop()`, which returned "false"
for some values that are defined outside of the loop (in a nested op, in
such a way that the value does not dominate the loop). This interface is
currently only used for LICM and there is no way to trigger this bug, so
no test is added.
* Always use the auto-generated `getInitArgs` function. Remove the
hand-written `getInitOperands` duplicate.
* Remove `hasIterOperands` and `getNumIterOperands`. The names were
inconsistent because the "arg" is called `initArgs` in TableGen. Use
`getInitArgs().size()` instead.
* Fix verification around ops with no results.
This patch adds a new transform operation `transform.loop.fuse_sibling`,
which given two loops, fuses them, assuming that they are independent.
The transform operation itself performs very basic checks to ensure
IR legality, and leaves the responsibility of ensuring independence on the user.
Reviewed By: ftynse
Differential Revision: https://reviews.llvm.org/D157069
`getConstantIntValue` extracts constant values from all constant-like ops, not just `arith::ConstantIndexOp`.
Differential Revision: https://reviews.llvm.org/D154356
There are existing implementations for `scf.for`, `scf.forall` and `affine.for`. This revision adds an interface method to the `LoopLikeOpInterface`.
* `scf.forall` now implements the `LoopLikeOpInterface`.
* The implementations of `scf.for` and `scf.forall` become interface method implementations. `affine.for` remains as is for the moment. (The implementation of `promoteIfSingleIteration` depepends on helper functions from `MLIRAffineAnalysis`, which cannot be used from `MLIRAffineDialect`, where the interface is currently implemented.)
* More efficient implementations of `promoteIfSingleIteration`. In particular, the `scf.forall` operation now inlines operations instead of cloning them. This also preserves handles when used from the transform dialect.
Differential Revision: https://reviews.llvm.org/D154343
Add an options object to allow control of the slice computation (for
both forward and backward slice). This makes the ABI stable, and also
allows avoiding an assert that makes the slice analysis unusable for
operations with multiple blocks.
Reviewed By: hanchung, nicolasvasilache
Differential Revision: https://reviews.llvm.org/D151520
This patch made a minor refactor of LoopCoalescing.cpp's walkLoops
templated method and placed it in Affine's LoopUtils.cpp/h.
This method is also renamed as coalescePerfectlyNestedLoops method. This
minor change enables this method to be invoked
by both the original LoopCoalescing pass as well as the newly introduced
loop.coalesce transform op.
The loop.coalesce transform op has the ability to coalesce affine, and
scf loop nests, leveraging existing LoopCoalescing
mechanism. I have created it inside the SCFTransformOps.td instead of
AffineTransformOps.td as it feels to be similar
in spirit as the loop.unroll op that can handle both scf and affine
loops. Please let me know if you feel that this op
should be moved into AffineTransformOps.td instead.
The testcase added illustrates loop.coalesce transform op working for
scf, affine loops (inner, outer) as well as
coalesced loop can be further unrolled (achieving composibility).
Reviewed By: ftynse
Differential Revision: https://reviews.llvm.org/D141202
The patch adds operations to `BlockAndValueMapping` and renames it to `IRMapping`. When operations are cloned, old operations are mapped to the cloned operations. This allows mapping from an operation to a cloned operation. Example:
```
Operation *opWithRegion = ...
Operation *opInsideRegion = &opWithRegion->front().front();
IRMapping map
Operation *newOpWithRegion = opWithRegion->clone(map);
Operation *newOpInsideRegion = map.lookupOrNull(opInsideRegion);
```
Migration instructions:
All includes to `mlir/IR/BlockAndValueMapping.h` should be replaced with `mlir/IR/IRMapping.h`. All uses of `BlockAndValueMapping` need to be renamed to `IRMapping`.
Reviewed By: rriddle, mehdi_amini
Differential Revision: https://reviews.llvm.org/D139665
The methods in `SideEffectUtils.h` (and their implementations in
`SideEffectUtils.cpp`) seem to have similar intent to methods already
existing in `SideEffectInterfaces.h`. Move the decleration (and
implementation) from `SideEffectUtils.h` (and `SideEffectUtils.cpp`)
into `SideEffectInterfaces.h` (and `SideEffectInterface.cpp`).
Also drop the `SideEffectInterface::hasNoEffect` method in favor of
`mlir::isMemoryEffectFree` which actually recurses into the operation
instead of just relying on the `hasRecursiveMemoryEffectTrait`
exclusively.
Differential Revision: https://reviews.llvm.org/D137857
Based on discussion in https://reviews.llvm.org/D134411, instead of
first modifying the inner most loop first followed by modifying the
outer loops from inside out, this patch restructures the logic to
start the modification from the outer most loop.
Differential Revision: https://reviews.llvm.org/D134832
The current approach for handling `iter_args` was to replace all uses
of the value that is used as `init` value with the corresponding
region block argument within the `scf.for`. This is not always
correct. Instead a more deliberate approach needs to be taken to
handle these. If the slice being fused represents a slice of the
destination operand of the untiled op, then
- Make the destination of the fused producer the `init` value of the
loop nest
- For the tiled and fused producer op created, replace the slice of
the destination operand with a slice of the corresponding region
iter arg of the innermost loop of the generated loop nest
Differential Revision: https://reviews.llvm.org/D134411
Fixes using the signed ceildiv op instead of incorrectly assuming positive loop bounds.
Adjusts the tests for above.
Differential Revision: https://reviews.llvm.org/D132953
mlir::TypedValue is a wrapper class for mlir::Values with a known type
getType will return the known type and all assignements will be checked
Also the tablegen Operation generator was adapted to use mlir::TypedValue
when appropriate
llvm::sort is beneficial even when we use the iterator-based overload,
since it can optionally shuffle the elements (to detect
non-determinism). However llvm::sort is not usable everywhere, for
example, in compiler-rt.
Reviewed By: nhaehnle
Differential Revision: https://reviews.llvm.org/D130406
This aligns the SCF dialect file layout with the majority of the dialects.
Reviewed By: jpienaar
Differential Revision: https://reviews.llvm.org/D128049
This patch adds support for tiling operations that implement the
TilingInterface.
- It separates the loop constructs that are used to iterate over tile
from the implementation of the tiling itself. For example, the use
of destructive updates is more related to use of scf.for for
iterating over tiles that are tensors.
- To test the transformation, TilingInterface is implemented for
LinalgOps. The separation of the looping constructs used from the
implementation of tile code generation greatly simplifies the
latter.
- The implementation of TilingInterface for LinalgOp is kept as an
external model for now till this approach can be fully flushed out
to replace the existing tiling + fusion approaches in Linalg.
Differential Revision: https://reviews.llvm.org/D127133
Introduce transform ops for "for" loops, in particular for peeling, software
pipelining and unrolling, along with a couple of "IR navigation" ops. These ops
are intended to be generalized to different kinds of loops when possible and
therefore use the "loop" prefix. They currently live in the SCF dialect as
there is no clear place to put transform ops that may span across several
dialects, this decision is postponed until the ops actually need to handle
non-SCF loops.
Additionally refactor some common utilities for transform ops into trait or
interface methods, and change the loop pipelining to be a returning pattern.
Reviewed By: springerm
Differential Revision: https://reviews.llvm.org/D127300
Using "replaceUsesOfWith" is incorrect because the same initializer value may appear multiple times.
For example, if the epilogue is needed when this loop is unrolled
```
%x:2 = scf.for ... iter_args(%arg1 = %c1, %arg2 = %c1) {
...
}
```
then both epilogue's arguments will be incorrectly renamed to use the same result index (note #1 in both cases):
```
%x_unrolled:2 = scf.for ... iter_args(%arg1 = %c1, %arg2 = %c1) {
...
}
%x_epilogue:2 = scf.for ... iter_args(%arg1 = %x_unrolled#1, %arg2 = %x_unrolled#1) {
...
}
```
The current implementation of `cloneWithNewYields` has a few issues
- It clones the loop body of the original loop to create a new
loop. This is very expensive.
- It performs `erase` operations which are incompatible when this
method is called from within a pattern rewrite. All erases need to
go through `PatternRewriter`.
To address these a new utility method `replaceLoopWithNewYields` is added
which
- moves the operations from the original loop into the new loop.
- replaces all uses of the original loop with the corresponding
results of the new loop
- use a call back to allow caller to generate the new yield values.
- the original loop is modified to just yield the basic block
arguments corresponding to the iter_args of the loop. This
represents a no-op loop. The loop itself is dead (since all its uses
are replaced), but is not removed. The caller is expected to erase
the op. Consequently, this method can be called from within a
`matchAndRewrite` method of a `PatternRewriter`.
The `cloneWithNewYields` could be replaces with
`replaceLoopWithNewYields`, but that seems to trigger a failure during
walks, potentially due to the operations being moved. That is left as
a TODO.
Differential Revision: https://reviews.llvm.org/D125147
The last remaining operations in the standard dialect all revolve around
FuncOp/function related constructs. This patch simply handles the initial
renaming (which by itself is already huge), but there are a large number
of cleanups unlocked/necessary afterwards:
* Removing a bunch of unnecessary dependencies on Func
* Cleaning up the From/ToStandard conversion passes
* Preparing for the move of FuncOp to the Func dialect
See the discussion at https://discourse.llvm.org/t/standard-dialect-the-final-chapter/6061
Differential Revision: https://reviews.llvm.org/D120624
