57 Commits

Author SHA1 Message Date
MLIR Team
4eef795a1d Computation slice update: adds parameters to insertBackwardComputationSlice which specify the source loop nest depth at which to perform iteration space slicing, and the destination loop nest depth at which to insert the compution slice.
Updates LoopFusion pass to take these parameters as command line flags for experimentation.

PiperOrigin-RevId: 226514297
2019-03-29 14:35:03 -07:00
MLIR Team
6892ffb896 Improve loop fusion algorithm by using a memref dependence graph.
Fixed TODO for reduction fusion unit test.

PiperOrigin-RevId: 226277226
2019-03-29 14:33:02 -07:00
MLIR Team
3b69230b3a Loop Fusion pass update: introduce utilities to perform generalized loop fusion based on slicing; encompasses standard loop fusion.
*) Adds simple greedy fusion algorithm to drive experimentation. This algorithm greedily fuses loop nests with single-writer/single-reader memref dependences to improve locality.
*) Adds support for fusing slices of a loop nest computation: fusing one loop nest into another by adjusting the source loop nest's iteration bounds (after it is fused into the destination loop nest). This is accomplished by solving for the source loop nest's IVs in terms of the destination loop nests IVs and symbols using the dependece polyhedron, then creating AffineMaps of these functions for the loop bounds of the fused source loop.
*) Adds utility function 'insertMemRefComputationSlice' which computes and inserts computation slice from loop nest surrounding a source memref access into the loop nest surrounding the destingation memref access.
*) Adds FlatAffineConstraints::toAffineMap function which returns and AffineMap which represents an equality contraint where one dimension identifier is represented as a function of all others in the equality constraint.
*) Adds multiple fusion unit tests.

PiperOrigin-RevId: 225842944
2019-03-29 14:30:13 -07:00
MLIR Team
b5424dd0cb Adds support for returning the direction of the dependence between memref accesses (distance/direction vectors).
Updates MemRefDependenceCheck to check and report on all memref access pairs at all loop nest depths.
Updates old and adds new memref dependence check tests.
Resolves multiple TODOs.

PiperOrigin-RevId: 220816515
2019-03-29 13:53:28 -07:00
Jacques Pienaar
cc9a6ed09d Initialize Pass with PassID.
The passID is not currently stored in Pass but this avoids the unused variable warning. The passID is used to uniquely identify passes, currently this is only stored/used in PassInfo.

PiperOrigin-RevId: 220485662
2019-03-29 13:50:34 -07:00
Jacques Pienaar
6f0fb22723 Add static pass registration
Add static pass registration and change mlir-opt to use it. Future work is needed to refactor the registration for PassManager usage.

Change build targets to alwayslink to enforce registration.

PiperOrigin-RevId: 220390178
2019-03-29 13:49:34 -07:00
MLIR Team
f28e4df666 Adds a dependence check to test whether two accesses to the same memref access the same element.
- Builds access functions and iterations domains for each access.
- Builds dependence polyhedron constraint system which has equality constraints for equated access functions and inequality constraints for iteration domain loop bounds.
- Runs elimination on the dependence polyhedron to test if no dependence exists between the accesses.
- Adds a trivial LoopFusion transformation pass with a simple test policy to test dependence between accesses to the same memref in adjacent loops.
- The LoopFusion pass will be extended in subsequent CLs.

PiperOrigin-RevId: 219630898
2019-03-29 13:47:13 -07:00