Commit Graph

15 Commits

Author SHA1 Message Date
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
Uday Bondhugula
8201e19e3d Introduce memref bound checking.
Introduce analysis to check memref accesses (in MLFunctions) for out of bound
ones. It works as follows:

$ mlir-opt -memref-bound-check test/Transforms/memref-bound-check.mlir

/tmp/single.mlir:10:12: error: 'load' op memref out of upper bound access along dimension tensorflow/mlir#1
      %x = load %A[%idxtensorflow/mlir#0, %idxtensorflow/mlir#1] : memref<9 x 9 x i32>
           ^
/tmp/single.mlir:10:12: error: 'load' op memref out of lower bound access along dimension tensorflow/mlir#1
      %x = load %A[%idxtensorflow/mlir#0, %idxtensorflow/mlir#1] : memref<9 x 9 x i32>
           ^
/tmp/single.mlir:10:12: error: 'load' op memref out of upper bound access along dimension tensorflow/mlir#2
      %x = load %A[%idxtensorflow/mlir#0, %idxtensorflow/mlir#1] : memref<9 x 9 x i32>
           ^
/tmp/single.mlir:10:12: error: 'load' op memref out of lower bound access along dimension tensorflow/mlir#2
      %x = load %A[%idxtensorflow/mlir#0, %idxtensorflow/mlir#1] : memref<9 x 9 x i32>
           ^
/tmp/single.mlir:12:12: error: 'load' op memref out of upper bound access along dimension tensorflow/mlir#1
      %y = load %B[%idy] : memref<128 x i32>
           ^
/tmp/single.mlir:12:12: error: 'load' op memref out of lower bound access along dimension tensorflow/mlir#1
      %y = load %B[%idy] : memref<128 x i32>
           ^
#map0 = (d0, d1) -> (d0, d1)
#map1 = (d0, d1) -> (d0 * 128 - d1)
mlfunc @test() {
  %0 = alloc() : memref<9x9xi32>
  %1 = alloc() : memref<128xi32>
  for %i0 = -1 to 9 {
    for %i1 = -1 to 9 {
      %2 = affine_apply #map0(%i0, %i1)
      %3 = load %0[%2tensorflow/mlir#0, %2tensorflow/mlir#1] : memref<9x9xi32>
      %4 = affine_apply #map1(%i0, %i1)
      %5 = load %1[%4] : memref<128xi32>
    }
  }
  return
}

- Improves productivity while manually / semi-automatically developing MLIR for
  testing / prototyping; also provides an indirect way to catch errors in
  transformations.

- This pass is an easy way to test the underlying affine analysis
  machinery including low level routines.

Some code (in getMemoryRegion()) borrowed from @andydavis cl/218263256.

While on this:

- create mlir/Analysis/Passes.h; move Pass.h up from mlir/Transforms/ to mlir/

- fix a bug in AffineAnalysis.cpp::toAffineExpr

TODO: extend to non-constant loop bounds (straightforward). Will transparently
work for all accesses once floordiv, mod, ceildiv are supported in the
AffineMap -> FlatAffineConstraints conversion.
PiperOrigin-RevId: 219397961
2019-03-29 13:46:08 -07:00
Chris Lattner
adbba70d82 Simplify FunctionPass to eliminate the CFGFunctionPass/MLFunctionPass
distinction.  FunctionPasses can now choose to get called on all functions, or
have the driver split CFG/ML Functions up for them.  NFC.

PiperOrigin-RevId: 218775885
2019-03-29 13:40:05 -07:00
River Riddle
792d1c25e4 Implement value type abstraction for attributes.
This is done by changing Attribute to be a POD interface around an underlying pointer storage and adding in-class support for isa/dyn_cast/cast.

PiperOrigin-RevId: 218764173
2019-03-29 13:39:19 -07:00
Uday Bondhugula
80610c2f49 Introduce Fourier-Motzkin variable elimination + other cleanup/support
- Introduce Fourier-Motzkin variable elimination to eliminate a dimension from
  a system of linear equalities/inequalities. Update isEmpty to use this.
  Since FM is only exact on rational/real spaces, an emptiness check based on
  this is guaranteed to be exact whenever it says the underlying set is empty;
  if it says, it's not empty, there may still be no integer points in it.
  Also, supports a version that computes "dark shadows".

- Test this by checking for "always false" conditionals in if statements.

- Unique IntegerSet's that are small (few constraints, few variables). This
  basically means the canonical empty set and other small sets that are
  likely commonly used get uniqued; allows checking for the canonical empty set
  by pointer. IntegerSet::kUniquingThreshold gives the threshold constraint size
  for uniqui'ing.

- rename simplify-affine-expr -> simplify-affine-structures

Other cleanup

- IntegerSet::numConstraints, AffineMap::numResults are no longer needed;
  remove them.
- add copy assignment operators for AffineMap, IntegerSet.
- rename Invalid() -> Null() on AffineExpr, AffineMap, IntegerSet
- Misc cleanup for FlatAffineConstraints API

PiperOrigin-RevId: 218690456
2019-03-29 13:38:24 -07:00
MLIR Team
5413239350 Adds Gaussian Elimination to FlatAffineConstraints.
- Adds FlatAffineConstraints::isEmpty method to test if there are no solutions to the system.
- Adds GCD test check if equality constraints have no solution.
- Adds unit test cases.

PiperOrigin-RevId: 218546319
2019-03-29 13:38:10 -07:00
Chris Lattner
8dda701a9c Add MLFunction::walk/walkPostOrder methods for doing a simple traversal of
operations.  This is a simplified form for the existing walker API.

PiperOrigin-RevId: 216754991
2019-03-29 13:28:26 -07:00
Nicolas Vasilache
1d3e7e2616 [MLIR] AffineMap value type
This CL applies the same pattern as AffineExpr to AffineMap: a simple struct
that acts as the storage is allocated in the bump pointer. The AffineMap is
immutable and accessed everywhere by value.

PiperOrigin-RevId: 216445930
2019-03-29 13:26:24 -07:00
MLIR Team
fe490043b0 Affine map composition.
*) Implements AffineValueMap forward substitution for AffineApplyOps.
*) Adds ComposeAffineMaps transformation pass, which composes affine maps for all loads/stores in an MLFunction.
*) Adds multiple affine map composition tests.

PiperOrigin-RevId: 216216446
2019-03-29 13:24:59 -07:00
Nicolas Vasilache
b55b407601 [RFC][MLIR] Use AffineExprRef in place of AffineExpr* in IR
This CL starts by replacing AffineExpr* with value-type AffineExprRef in a few
places in the IR. By a domino effect that is pretty telling of the
inconsistencies in the codebase, const is removed where it makes sense.

The rationale is that the decision was concisously made that unique'd types
have pointer semantics without const specifier. This is fine but we should be
consistent. In the end, the only logical invariant is that there should never
be such a thing as a const AffineExpr*, const AffineMap* or const IntegerSet*
in our codebase.

This CL takes a number of shortcuts to killing const with fire, in particular
forcing const AffineExprRef to return the underlying non-const
AffineExpr*. This will be removed once AffineExpr* has disappeared in
containers but for now such shortcuts allow a bit of sanity in this long quest
for cleanups.

The **only** places where const AffineExpr*, const AffineMap* or const
IntegerSet* may still appear is by transitive needs from containers,
comparison operators etc.

There is still one major thing remaining here: figure out why cast/dyn_cast
return me a const AffineXXX*, which in turn requires a bunch of ugly
const_casts. I suspect this is due to the classof
taking const AffineXXXExpr*. I wonder whether this is a side effect of 1., if
it is coming from llvm itself (I'd doubt it) or something else (clattner@?)

In light of this, the whole discussion about const makes total sense to me now
and I would systematically apply the rule that in the end, we should never
have any const XXX in our codebase for unique'd types (assuming we can remove
them all in containers and no additional constness constraint is added on us
from the outside world).

PiperOrigin-RevId: 215811554
2019-03-29 13:23:05 -07:00
Nicolas Vasilache
544f5e7a9b [MLIR] Remove uses of AffineExpr* outside of IR
This CL uniformizes the uses of AffineExprWrap outside of IR.
The public API of AffineExpr builder is modified to only use AffineExprWrap.
A few places access AffineExprWrap.expr, this is only while the API is in
transition to easily keep track (i.e. make expr private and let the compiler
track the errors).

Parser.cpp exhibits patterns that are dependent on nullptr values so
converting it is left for another CL.

PiperOrigin-RevId: 215642005
2019-03-29 13:22:35 -07:00
Jacques Pienaar
fb3116f59e Add PassResult and have passes return PassResult to indicate failure/success.
For FunctionPass's for passes that want to stop upon error encountered.

PiperOrigin-RevId: 213058651
2019-03-29 13:13:55 -07:00
Uday Bondhugula
d5416f299e Complete AffineExprFlattener based simplification for floordiv/ceildiv.
- handle floordiv/ceildiv in AffineExprFlattener; update the simplification to
  work even if mod/floordiv/ceildiv expressions appearing in the tree can't be eliminated.
- refactor the flattening / analysis to move it out of lib/Transforms/
- fix MutableAffineMap::isMultipleOf
- add AffineBinaryOpExpr:getAdd/getMul/... utility methods

PiperOrigin-RevId: 211540536
2019-03-29 13:09:18 -07:00
Uday Bondhugula
0122a99cbb Affine expression analysis and simplification.
Outside of IR/
- simplify a MutableAffineMap by flattening the affine expressions
- add a simplify affine expression pass that uses this analysis
- update the FlatAffineConstraints API (to be used in the next CL)

In IR:
- add isMultipleOf and getKnownGCD for AffineExpr, and make the in-IR
  simplication of simplifyMod simpler and more powerful.
- rename the AffineExpr visitor methods to distinguish b/w visiting and
  walking, and to simplify API names based on context.

The next CL will use some of these for the loop unrolling/unroll-jam to make
the detection for the need of cleanup loop powerful/non-trivial.

A future CL will finally move this simplification to FlatAffineConstraints to
make it more powerful. For eg., currently, even if a mod expr appearing in a
part of the expression tree can't be simplified, the whole thing won't be
simplified.

PiperOrigin-RevId: 211012256
2019-03-29 13:07:44 -07:00