Commit Graph

11 Commits

Author SHA1 Message Date
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
Nicolas Vasilache
8ebb6ff171 [MLIR] Sketch AffineExpr value type
This CL sketches what it takes for AffineExpr to fully have by-value semantics
and not be a not-so-smart pointer anymore.

This essentially makes the underyling class a simple storage struct and
implements the operations on the value type directly. Since there is no
forwarding of operations anymore, we can full isolate the storage class and
make a hard visibility barrier by moving detail::AffineExpr into
AffineExprDetail.h.

AffineExprDetail.h is only included where storage-related information is
needed.

PiperOrigin-RevId: 216385459
2019-03-29 13:25:42 -07:00
Nicolas Vasilache
6707c7bea1 [MLIR] AffineExpr final cleanups
This CL:
1. performs the global codemod AffineXExpr->AffineXExprClass and
AffineXExprRef -> AffineXExpr;
2. simplifies function calls by removing the redundant MLIRContext parameter;
3. adds missing binary operator versions of scalar op AffineExpr where it
makes sense.

PiperOrigin-RevId: 216242674
2019-03-29 13:25:14 -07:00
Nicolas Vasilache
ce2edea135 [MLIR] Cleanup AffineExpr
This CL introduces a series of cleanups for AffineExpr value types:
1. to make it clear that the value types should be used, the pointer
AffineExpr types are put in the detail namespace. Unfortunately, since the
value type operator-> only forwards to the underlying pointer type, we
still
need to expose this in the include file for now;
2. AffineExprKind is ok to use, it thus comes out of detail and thus of
AffineExpr
3. getAffineDimExpr, getAffineSymbolExpr, getAffineConstantExpr are
similarly
extracted as free functions and their naming is mande consistent across
Builder, MLContext and AffineExpr
4. AffineBinaryOpEx::simplify functions are made into static free
functions.
In particular it is moved away from AffineMap.cpp where it does not belong
5. operator AffineExprType is made explicit
6. uses the binary operators everywhere possible
7. drops the pointer usage everywhere outside of AffineExpr.cpp,
MLIRContext.cpp and AsmPrinter.cpp

PiperOrigin-RevId: 216207212
2019-03-29 13:24:45 -07:00
Nicolas Vasilache
4911978f7e [MLIR] Value types for AffineXXXExpr
This CL makes AffineExprRef into a value type.

Notably:
1. drops llvm isa, cast, dyn_cast on pointer type and uses member functions on
the value type. It may be possible to still use classof  (in a followup CL)
2. AffineBaseExprRef aggressively casts constness away: if we mean the type is
immutable then let's jump in with both feet;
3. Drop implicit casts to the underlying pointer type because that always
results in surprising behavior and is not needed in practice once enough
cleanup has been applied.

The remaining negative I see is that we still need to mix operator. and
operator->. There is an ugly solution that forwards the methods but that ends
up duplicating the class hierarchy which I tried to avoid as much as
possible. But maybe it's not that bad anymore since AffineExpr.h would still
contain a single class hierarchy (the duplication would be impl detail in.cpp)

PiperOrigin-RevId: 216188003
2019-03-29 13:24:31 -07:00
Nicolas Vasilache
5b8017db18 [MLIR] Templated AffineExprBaseRef
This CL implements AffineExprBaseRef as a templated type to allow LLVM-style
casts to work properly. This also allows making AffineExprBaseRef::expr
private.

To achieve this, it is necessary to use llvm::simplify_type and make
AffineConstExpr derive from both AffineExpr and llvm::simplify<AffineExprRef>.
Note that llvm::simplify_type is just an interface to enable the proper
template resolution of isa/cast/dyn_cast but it otherwise holds no value.

Lastly note that certain dyn_cast operations wanted the const AffineExpr* form
of AffineExprBaseRef so I made the implicit constructor take that by default
and documented the immutable behavior. I think this is consistent with the
decision to make unique'd type immutable by convention and never use const on
them.

PiperOrigin-RevId: 215642247
2019-03-29 13:22:49 -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
Uday Bondhugula
0ebc927f2f Fix MLIR's floordiv, ceildiv, and mod for constant inputs (for negative lhs's)
- introduce mlir::{floorDiv, ceilDiv, mod} for constant inputs in
  mlir/Support/MathExtras.h
- consistently use these everywhere in IR, Analysis, and Transforms.

PiperOrigin-RevId: 215580677
2019-03-29 13:21:53 -07:00
Uday Bondhugula
ec35e51f6d Change loop step to be a positive integral constant
Changing this per discussion on mlir-team. Spec updated.

PiperOrigin-RevId: 214868483
2019-03-29 13:21:13 -07:00
Uday Bondhugula
ab4797229c Extend loop unroll/unroll-and-jam to affine bounds + refactor related code.
- extend loop unroll-jam similar to loop unroll for affine bounds
- extend both loop unroll/unroll-jam to deal with cleanup loop for non multiple
  of unroll factor.
- extend promotion of single iteration loops to work with affine bounds
- fix typo bugs in loop unroll
- refactor common code b/w loop unroll and loop unroll-jam
- move prototypes of non-pass transforms to LoopUtils.h
- add additional builder methods.
- introduce loopUnrollUpTo(factor) to unroll by either factor or trip count,
  whichever is less.
- remove Statement::isInnermost (not used for now - will come back at the right
  place/in right form later)

PiperOrigin-RevId: 213471227
2019-03-29 13:15:06 -07:00
Uday Bondhugula
64812a56c7 Extend getConstantTripCount to deal with a larger subset of loop bounds; make loop
unroll/unroll-and-jam more powerful; add additional affine expr builder methods

- use previously added analysis/simplification to infer multiple of unroll
  factor trip counts, making loop unroll/unroll-and-jam more general.

- for loop unroll, support bounds that are single result affine map's with the
  same set of operands. For unknown loop bounds, loop unroll will now work as
  long as trip count can be determined to be a multiple of unroll factor.

- extend getConstantTripCount to deal with single result affine map's with the
  same operands. move it to mlir/Analysis/LoopAnalysis.cpp

- add additional builder utility methods for affine expr arithmetic
  (difference, mod/floordiv/ceildiv w.r.t postitive constant). simplify code to
  use the utility methods.

- move affine analysis routines to AffineAnalysis.cpp/.h from
  AffineStructures.cpp/.h.

- Rename LoopUnrollJam to LoopUnrollAndJam to match class name.

- add an additional simplification for simplifyFloorDiv, simplifyCeilDiv

- Rename AffineMap::getNumOperands() getNumInputs: an affine map by itself does
  not have operands. Operands are passed to it through affine_apply, from loop
  bounds/if condition's, etc., operands are stored in the latter.

This should be sufficiently powerful for now as far as unroll/unroll-and-jam go for TPU
code generation, and can move to other analyses/transformations.

Loop nests like these are now unrolled without any cleanup loop being generated.

  for %i = 1 to 100 {
    // unroll factor 4: no cleanup loop will be generated.
    for %j = (d0) -> (d0) (%i) to (d0) -> (5*d0 + 3) (%i) {
      %x = "foo"(%j) : (affineint) -> i32
    }
  }

  for %i = 1 to 100 {
    // unroll factor 4: no cleanup loop will be generated.
    for %j = (d0) -> (d0) (%i) to (d0) -> (d0 - d mod 4 - 1) (%i) {
      %y = "foo"(%j) : (affineint) -> i32
    }
  }

  for %i = 1 to 100 {
    for %j = (d0) -> (d0) (%i) to (d0) -> (d0 + 128) (%i) {
      %x = "foo"() : () -> i32
    }
  }

TODO(bondhugula): extend this to LoopUnrollAndJam as well in the next CL (with minor
changes).

PiperOrigin-RevId: 212661212
2019-03-29 13:13:00 -07:00