Commit Graph

19 Commits

Author SHA1 Message Date
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
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 8a663870e8 Support for affine integer sets
- introduce affine integer sets into the IR
- parse and print affine integer sets (both inline or outlined) similar to
  affine maps
- use integer set for IfStmt's conditional, and implement parsing of IfStmt's
  conditional

- fixed an affine expr paren omission bug while one this.

TODO: parse/represent/print MLValue operands to affine integer set references.
PiperOrigin-RevId: 207779408
2019-03-29 12:56:58 -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
Tatiana Shpeisman a0a6414ca2 Implement ML function arguments. Add representation for argument list in ML Function using TrailingObjects template. Implement argument iterators, parsing and printing.
Unrelated minor change - remove OperationStmt::dropReferences(). Since MLFunction does not have cyclic operand references (it's an AST) destruction can be safely done w/o a special pass to drop references.

PiperOrigin-RevId: 207583024
2019-03-29 12:55:47 -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
Tatiana Shpeisman 2dcdec8910 Fix segfaults when printing unlinked statements, instructions and blocks. Fancy printing requires a pointer to the function since SSA values get function-specific names. This CL adds checks to ensure that we don't dereference null pointers in unliked objects. Unlinked statements, instructions and blocks are printed as <<UNLINKED STATEMENT>> etc.
PiperOrigin-RevId: 207293992
2019-03-29 12:55:06 -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
Chris Lattner 8eaf382734 Use SFINAE to generalize << overloads, give 'constant' a pretty form,
generalize the asmprinters handling of pretty names to allow arbitrary sugar to
be dumped on various constructs.  Give CFG function arguments nice "arg0" names
like MLFunctions get, and give constant integers pretty names like %c37 for a
constant 377

PiperOrigin-RevId: 206953080
2019-03-29 12:52:07 -07:00
Chris Lattner 48dbfb48d5 Enhance MLIRContext and operations with the ability to register diagnostic
handlers and to feed them with errors and warnings produced by the compiler.
Enhance Operation to be able to get its own MLIRContext on demand, simplifying
some clients.  Change the verifier to emit certain errors with the diagnostic
handler.

This is steps towards reworking the verifier and diagnostic propagation but is
itself not particularly useful.  More to come.

PiperOrigin-RevId: 206948643
2019-03-29 12:51:52 -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
Tatiana Shpeisman 43e2a13605 Use for statement directly as an operand instead of having it pretend to be an induction variable.
PiperOrigin-RevId: 206759180
2019-03-29 12:49:50 -07:00
Tatiana Shpeisman c8b0273f19 Implement induction variables. Pretty print induction variable operands as %i<ssa value number>. Add support for future pretty printing of ML function arguments as %arg<ssa value number>.
Induction variables are implemented by inheriting ForStmt from MLValue. ForStmt provides APIs that make this design decision invisible to the ForStmt users.

This CL in combination with cl/206253643 resolves  http://b/111769060.

PiperOrigin-RevId: 206655937
2019-03-29 12:49:36 -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
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
Tatiana Shpeisman 1b24c48b91 Scaffolding for convertToCFG pass that replaces all instances of ML functions with equivalent CFG functions. Traverses module MLIR, generates CFG functions (empty for now) and removes ML functions. Adds Transforms library and tests.
PiperOrigin-RevId: 205848367
2019-03-29 12:41:15 -07:00
Tatiana Shpeisman ad9894a2fd Use LLVM dynamic dispatch to disambiguate between StmtBlock subclasses.
PiperOrigin-RevId: 204614520
2019-03-29 12:33:41 -07:00
Tatiana Shpeisman 8efc06dc2c Refactor implementation of Statement class heirarchy to use statement block.
Use LLVM double-link with parent list to store statements within a block.

PiperOrigin-RevId: 204515541
2019-03-29 12:33:28 -07:00