TL;DR the following API functions have been merged
```
void populateFoldUnitExtentDimsViaReshapesPatterns(RewritePatternSet &patterns);
void populateFoldUnitExtentDimsViaSlicesPatterns(RewritePatternSet &patterns);
```
into
```
void populateFoldUnitExtentDimsPatterns(RewritePatternSet &patterns,
ControlDropUnitDims &options);
```
To use the previous functionality use
```
ControlDropUnitDims options;
// By default options.rankReductionStrategy is
// ControlDropUnitDims::RankReductionStrategy::ReassociativeReshape.
populateFoldUnitExtentDimsPatterns(patterns, options);
```
and
```
ControlDropUnitDims options;
options.rankReductionStrategy = ControlDropUnitDims::RankReductionStrategy::ExtractInsertSlice
populateFoldUnitExtentDimsPatterns(patterns, options);
```
This pass is quite old and needed to be updated based on the current
approach to transformations in Linalg
- Instead of two patterns, one to just remove loop dimensions that are
unit extent (and using 0 in the indexing maps), and another to drop
the unit-extents in the operand shapes, combine into a single
transformation. This avoid creating an intermediate step with
indexing maps having 0's in the domains exp ressions.
- Expose the core transformation as a utility function and add a
pattern that calls this transformation.
This is a mostly NFC change, apart from the API change and dropping
the patterns/test that only dropped the loops that are unit extents.
Differential Revision: https://reviews.llvm.org/D155518
