Commit Graph

48 Commits

Author SHA1 Message Date
River Riddle 755538328b Recommit: Define a AffineOps dialect as well as an AffineIfOp operation. Replace all instances of IfInst with AffineIfOp and delete IfInst.
PiperOrigin-RevId: 231342063
2019-03-29 15:59:30 -07:00
Nicolas Vasilache ae772b7965 Automated rollback of changelist 231318632.
PiperOrigin-RevId: 231327161
2019-03-29 15:42:38 -07:00
River Riddle 5ecef2b3f6 Define a AffineOps dialect as well as an AffineIfOp operation. Replace all instances of IfInst with AffineIfOp and delete IfInst.
PiperOrigin-RevId: 231318632
2019-03-29 15:42:08 -07:00
River Riddle 75c21e1de0 Wrap cl::opt flags within passes in a category with the pass name. This improves the help output of tools like mlir-opt.
Example:

dma-generate options:

  -dma-fast-mem-capacity                 - Set fast memory space  ...
  -dma-fast-mem-space=<uint>             - Set fast memory space  ...

loop-fusion options:

  -fusion-compute-tolerance=<number>     - Fractional increase in  ...
  -fusion-maximal                        - Enables maximal loop fusion

loop-tile options:

  -tile-size=<uint>                      - Use this tile size for  ...

loop-unroll options:

  -unroll-factor=<uint>                  - Use this unroll factor  ...
  -unroll-full                           - Fully unroll loops
  -unroll-full-threshold=<uint>          - Unroll all loops with  ...
  -unroll-num-reps=<uint>                - Unroll innermost loops  ...

loop-unroll-jam options:

  -unroll-jam-factor=<uint>              - Use this unroll jam factor ...

PiperOrigin-RevId: 231019363
2019-03-29 15:39:38 -07:00
River Riddle c3424c3c75 Allow operations to hold a blocklist and add support for parsing/printing a block list for verbose printing.
PiperOrigin-RevId: 230951462
2019-03-29 15:37:37 -07:00
Chris Lattner 7974889f54 Update and generalize various passes to work on both CFG and ML functions,
simplifying them in minor ways.  The only significant cleanup here
is the constant folding pass.  All the other changes are simple and easy,
but this is still enough to shrink the compiler by 45LOC.

The one pass left to merge is the CSE pass, which will be move involved, so I'm
splitting it out to its own patch (which I'll tackle right after this).

This is step 28/n towards merging instructions and statements.

PiperOrigin-RevId: 227328115
2019-03-29 14:49:52 -07:00
Chris Lattner 456ad6a8e0 Standardize naming of statements -> instructions, revisting the code base to be
consistent and moving the using declarations over.  Hopefully this is the last
truly massive patch in this refactoring.

This is step 21/n towards merging instructions and statements, NFC.

PiperOrigin-RevId: 227178245
2019-03-29 14:44:30 -07:00
Chris Lattner 315a466aed Rename BasicBlock and StmtBlock to Block, and make a pass cleaning it up. I did not make an effort to rename all of the 'bb' names in the codebase, since they are still correct and any specific missed once can be fixed up on demand.
The last major renaming is Statement -> Instruction, which is why Statement and
Stmt still appears in various places.

This is step 19/n towards merging instructions and statements, NFC.

PiperOrigin-RevId: 227163082
2019-03-29 14:43:58 -07:00
Chris Lattner 69d9e990fa Eliminate the using decls for MLFunction and CFGFunction standardizing on
Function.

This is step 18/n towards merging instructions and statements, NFC.

PiperOrigin-RevId: 227139399
2019-03-29 14:43:13 -07:00
Chris Lattner 5187cfcf03 Merge Operation into OperationInst and standardize nomenclature around
OperationInst.  This is a big mechanical patch.

This is step 16/n towards merging instructions and statements, NFC.

PiperOrigin-RevId: 227093712
2019-03-29 14:42:23 -07:00
Chris Lattner 1301f907a1 Refactor ForStmt: having it contain a StmtBlock instead of subclassing
StmtBlock.  This is more consistent with IfStmt and also conceptually makes
more sense - a forstmt "isn't" its body, it contains its body.

This is step 1/N towards merging BasicBlock and StmtBlock.  This is required
because in the new regime StmtBlock will have a use list (just like BasicBlock
does) of operands, and ForStmt already has a use list for its induction
variable.

This is a mechanical patch, NFC.

PiperOrigin-RevId: 226684158
2019-03-29 14:35:19 -07:00
Uday Bondhugula 4a3e4e8ea7 loop-unroll - add function callback argument for outside targets to
provide unroll factors, and a cmd line argument to specify number of
innermost loop unroll repetitions.

- add function callback parameter for outside targets to provide unroll factors
- add a cmd line parameter to repeatedly apply innermost loop unroll a certain
  number of times (to avoid using -loop-unroll -loop-unroll ...; instead
  -unroll-num-reps=2).
- implement the callback for a target
- update test cases / usage

PiperOrigin-RevId: 225843191
2019-03-29 14:30:28 -07:00
Alex Zinenko cb40633969 Move definitions of lopoUnroll* functions to LoopUtils.cpp.
These functions are declared in Transforms/LoopUtils.h (included to the
Transforms/Utils library) but were defined in the loop unrolling pass in
Transforms/LoopUnroll.cpp.  As a result, targets depending only on
TransformUtils library but not on Transforms could get link errors.  Move the
definitions to Transforms/Utils/LoopUtils.cpp where they should actually live.
This does not modify any code.

PiperOrigin-RevId: 221508882
2019-03-29 13:57:44 -07:00
Uday Bondhugula e0623d4b86 Automatic DMA generation for simple cases.
- constant bounded memory regions, static shapes, no handling of
  overlapping/duplicate regions (through union) for now; also only, load memory
  op's.
- add build methods for DmaStartOp, DmaWaitOp.
- move getMemoryRegion() into Analysis/Utils and expose it.
- fix addIndexSet, getMemoryRegion() post switch to exclusive upper bounds;
  update test cases for memref-bound-check and memref-dependence-check for
  exclusive bounds (missed in a previous CL)

PiperOrigin-RevId: 220729810
2019-03-29 13:53:14 -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
Uday Bondhugula 6cd5d5c544 Introduce loop tiling code generation (hyper-rectangular case)
- simple perfectly nested band tiling with fixed tile sizes.
- only the hyper-rectangular case is handled, with other limitations of
  getIndexSet applying (constant loop bounds, etc.);  once
  the latter utility is extended, tiled code generation should become more
  general.
- Add FlatAffineConstraints::isHyperRectangular()

PiperOrigin-RevId: 220324933
2019-03-29 13:49:05 -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
Lei Zhang 52a0e58bdb Change typedef to using to be consistent across the codebase
Google C++ style guide also prefers using to typedef.

PiperOrigin-RevId: 218541849
2019-03-29 13:37:55 -07:00
Jacques Pienaar 764fd035b0 Split BuiltinOps out of StandardOps.
* Move Return, Constant and AffineApply out into BuiltinOps;
* BuiltinOps are always registered, while StandardOps follow the same dynamic registration;
* Kept isValidX in MLValue as we don't have a verify on AffineMap so need to keep it callable from Parser (I wanted to move it to be called in verify instead);

PiperOrigin-RevId: 216592527
2019-03-29 13:28:12 -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
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 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 591fa9698e Change behavior of loopUnrollFull with unroll factor 1
Using loopUnrollFull with unroll factor 1 should promote the loop body as
opposed to doing nothing.

PiperOrigin-RevId: 214812126
2019-03-29 13:20:59 -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
Tatiana Shpeisman 52111cefc0 Store 'then' clause statements directly in the 'if' statement.
Also a few minor changes.

PiperOrigin-RevId: 213359024
2019-03-29 13:14:23 -07:00
Uday Bondhugula 37a3f638ea Misc changes to builder's and Transforms/ API to allow code generation.
- add builder method for ReturnOp
- expose API from Transforms/ to work on specific ML statements (do this for
  LoopUnroll, LoopUnrollAndJam)
- add MLFuncBuilder::getForStmtBodyBuilder, ::getBlock

PiperOrigin-RevId: 213074178
2019-03-29 13:14:09 -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 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
Uday Bondhugula 3bae041e5d Add utility to promote single iteration loops. Add methods for getting constant
loop counts. Improve / refactor loop unroll / loop unroll and jam.

- add utility to remove single iteration loops.
- use this utility to promote single iteration loops after unroll/unroll-and-jam
- use loopUnrollByFactor for loopUnrollFull and remove most of the latter.
- add methods for getting constant loop trip count

PiperOrigin-RevId: 212039569
2019-03-29 13:11:21 -07:00
Uday Bondhugula e9fb4b492d Introduce loop unroll jam transformation.
- for test purposes, the unroll-jam pass unroll jams the first outermost loop.

While on this:
- fix StmtVisitor to allow overriding of function to iterate walk over children
  of a stmt.

PiperOrigin-RevId: 210644813
2019-03-29 13:07:30 -07:00
Tatiana Shpeisman d32a28c520 Implement operands for the lower and upper bounds of the for statement.
This revamps implementation of the loop bounds in the ForStmt, using general representation that supports operands. The frequent case of constant bounds is supported
via special access methods.

This also includes:
- Operand iterators for the Statement class.
- OpPointer::is() method to query the class of the Operation.
- Support for the bound shorthand notation parsing and printing.
- Validity checks for the bound operands used as dim ids and symbols

I didn't mean this CL to be so large. It just happened this way, as one thing led to another.

PiperOrigin-RevId: 210204858
2019-03-29 13:05:16 -07:00
Chris Lattner 956e0f7e21 Push location information more tightly into the IR, providing space for every
operation and statement to have a location, and make it so a location is
required to be specified whenever you make one (though a null location is still
allowed).  This is to encourage compiler authors to propagate loc info
properly, allowing our failability story to work well.

This is still a WIP - it isn't clear if we want to continue abusing Attribute
for location information, or whether we should introduce a new class heirarchy
to do so.  This is good step along the way, and unblocks some of the tf/xla
work that builds upon it.

PiperOrigin-RevId: 210001406
2019-03-29 13:04:33 -07:00
Uday Bondhugula 00bed4bd99 Extend loop unrolling to unroll by a given factor; add builder for affine
apply op.

- add builder for AffineApplyOp (first one for an operation that has
  non-zero operands)
- add support for loop unrolling by a given factor; uses the affine apply op
  builder.

While on this, change 'step' of ForStmt to be 'unsigned' instead of
AffineConstantExpr *. Add setters for ForStmt lb, ub, step.

Sample Input:

// CHECK-LABEL: mlfunc @loop_nest_unroll_cleanup() {
mlfunc @loop_nest_unroll_cleanup() {
  for %i = 1 to 100 {
    for %j = 0 to 17 {
      %x = "addi32"(%j, %j) : (affineint, affineint) -> i32
      %y = "addi32"(%x, %x) : (i32, i32) -> i32
    }
  }
  return
}

Output:

$ mlir-opt -loop-unroll -unroll-factor=4 /tmp/single2.mlir
#map0 = (d0) -> (d0 + 1)
#map1 = (d0) -> (d0 + 2)
#map2 = (d0) -> (d0 + 3)
mlfunc @loop_nest_unroll_cleanup() {
  for %i0 = 1 to 100 {
    for %i1 = 0 to 17 step 4 {
      %0 = "addi32"(%i1, %i1) : (affineint, affineint) -> i32
      %1 = "addi32"(%0, %0) : (i32, i32) -> i32
      %2 = affine_apply #map0(%i1)
      %3 = "addi32"(%2, %2) : (affineint, affineint) -> i32
      %4 = affine_apply #map1(%i1)
      %5 = "addi32"(%4, %4) : (affineint, affineint) -> i32
      %6 = affine_apply #map2(%i1)
      %7 = "addi32"(%6, %6) : (affineint, affineint) -> i32
    }
    for %i2 = 16 to 17 {
      %8 = "addi32"(%i2, %i2) : (affineint, affineint) -> i32
      %9 = "addi32"(%8, %8) : (i32, i32) -> i32
    }
  }
  return
}

PiperOrigin-RevId: 209676220
2019-03-29 13:03:38 -07:00
Uday Bondhugula 98a24881d3 ShortLoopUnroll - bug fix.
Collect loops through a post order walk instead of a pre-order so that loops
are collected from inner loops are collected before outer surrounding ones.

Add a complex test case.

PiperOrigin-RevId: 209041057
2019-03-29 13:01:22 -07:00
Uday Bondhugula 3e92be9c71 Move Pass.{h,cpp} from lib/IR/ to lib/Transforms/.
PiperOrigin-RevId: 208571437
2019-03-29 12:59:07 -07:00
Chris Lattner 8159186f57 Rework the cloning infrastructure for statements to be able to take and update
an operand mapping, which simplifies it a bit.  Implement cloning for IfStmt,
rename getThenClause() to getThen() which is unambiguous and less repetitive in
use cases.

PiperOrigin-RevId: 207915990
2019-03-29 12:57:38 -07:00
Uday Bondhugula d8490d8d4f Loop unrolling pass update
- fix/complete forStmt cloning for unrolling to work for outer loops
- create IV const's only when needed
- test outer loop unrolling by creating a short trip count unroll pass for
  loops with trip counts <= <parameter>
- add unrolling test cases for multiple op results, outer loop unrolling
- fix/clean up StmtWalker class while on this
- switch unroll loop iterator values from i32 to affineint

PiperOrigin-RevId: 207645967
2019-03-29 12:56:16 -07:00
Uday Bondhugula 65b6e73245 Loop unrolling update.
- deal with non-operation stmt's (if/for stmt's) in loops being unrolled
  (unrolling of non-innermost loops works).
- update uses in unrolled bodies to use results of new operations that may be
  introduced in the unrolled bodies.

Unrolling now works for all kinds of loop nests - perfect nests, imperfect
nests, loops at any depth, and with any kind of operation in the body. (IfStmt
support not done, hence untested there).

Added missing dump/print method for StmtBlock.

TODO: add test case for outer loop unrolling.
PiperOrigin-RevId: 207314286
2019-03-29 12:55:19 -07:00
Uday Bondhugula 2a003256ae MLStmt cloning and IV replacement for loop unrolling, add constant pool to
MLFunctions.

- MLStmt cloning and IV replacement
- While at this, fix the innermostLoopGatherer to actually gather all the
  innermost loops (it was stopping its walk at the first innermost loop it
  found)
- Improve comments for MLFunction statement classes, fix inheritance order.

- Fixed StmtBlock destructor.

PiperOrigin-RevId: 207049173
2019-03-29 12:53:02 -07:00
Tatiana Shpeisman 8189a12bce Clean up and extend MLFuncBuilder to allow creating statements in the middle of a statement block. Rename Statement::getFunction() and StmtBlock()::getFunction() to findFunction() to make it clear that this is not a constant time getter.
Fix b/112039912 - we were recording 'i' instead of '%i' for loop induction variables causing "use of undefined SSA value" error.

PiperOrigin-RevId: 206884644
2019-03-29 12:51:38 -07:00
Uday Bondhugula dfd48dc24c LoopUnroll post order walk: fix misleading naming
PiperOrigin-RevId: 206609084
2019-03-29 12:48:44 -07:00
Chris Lattner 12adbeb872 Prepare for implementation of TensorFlow passes:
- Sketch out a TensorFlow/IR directory that will hold op definitions and common TF support logic.  We will eventually have TensorFlow/TF2HLO, TensorFlow/Grappler, TensorFlow/TFLite, etc.
 - Add sketches of a Switch/Merge op definition, including some missing stuff like the TwoResults trait.  Add a skeleton of a pass to raise this form.
 - Beef up the Pass/FunctionPass definitions slightly, moving the common code out of LoopUnroll.cpp into a new IR/Pass.cpp file.
 - Switch ConvertToCFG.cpp to be a ModulePass.
 - Allow _ to start bare identifiers, since this is important for TF attributes.

PiperOrigin-RevId: 206502517
2019-03-29 12:47:25 -07:00
Uday Bondhugula 0af97111d2 Stmt visitors and walkers.
- Update InnermostLoopGatherer to use a post order traversal (linear
  time/single traversal).
- Drop getNumNestedLoops().
- Update isInnermost() to use the StmtWalker.

When using return values in conjunction with walkers, the StmtWalker CRTP
pattern doesn't appear to be of any use. It just requires overriding nearly all
of the methods, which is what InnermostLoopGatherer currently does. Please see
FIXME/ENLIGHTENME comments. TODO: figure this out from this CL discussion.

Note
- Comments on visitor/walker base class are out of date; will update when this
  CL is finalized.

PiperOrigin-RevId: 206340901
2019-03-29 12:46:17 -07:00
Tatiana Shpeisman 9ebd3c7df8 Implement MLValue, statement operands, operation statement operands and values. ML functions now have full support for expressing operations. Induction variables, function arguments and return values are still todo.
PiperOrigin-RevId: 206253643
2019-03-29 12:46:04 -07:00
Chris Lattner f964bad6d1 Implement a proper function list in module, which auto-maintain the parent
pointer, and ensure that functions are deleted when the module is destroyed.

This exposed the fact that MLFunction had no dtor, and that the dtor in
CFGFunction was broken with cyclic references.  Fix both of these problems.

PiperOrigin-RevId: 206051666
2019-03-29 12:43:57 -07:00
Uday Bondhugula a0abd666a7 Sketch out loop unrolling transformation.
- Implement a full loop unroll for innermost loops.
- Use it to implement a pass that unroll all the innermost loops of all
  mlfunction's in a module. ForStmt's parsed currently have constant trip
  counts (and constant loop bounds).
- Implement StmtVisitor based (Visitor pattern)

Loop IVs aren't currently parsed and represented as SSA values. Replacing uses
of loop IVs in unrolled bodies is thus a TODO. Class comments are sparse at some places - will add them after one round of comments.

A cmd-line flag triggers this for now.

Original:

mlfunc @loops() {
  for x = 1 to 100 step 2 {
    for x = 1 to 4 {
      "Const"(){value: 1} : () -> ()
    }
  }
  return
}

After unrolling:

mlfunc @loops() {
  for x = 1 to 100 step 2 {
    "Const"(){value: 1} : () -> ()
    "Const"(){value: 1} : () -> ()
    "Const"(){value: 1} : () -> ()
    "Const"(){value: 1} : () -> ()
  }
  return
}

PiperOrigin-RevId: 205933235
2019-03-29 12:43:01 -07:00