- introduce splat op in standard dialect (currently for int/float/index input
type, output type can be vector or statically shaped tensor)
- implement LLVM lowering (when result type is 1-d vector)
- add constant folding hook for it
- while on Ops.cpp, fix some stale names
Signed-off-by: Uday Bondhugula <uday@polymagelabs.com>
Closestensorflow/mlir#141
COPYBARA_INTEGRATE_REVIEW=https://github.com/tensorflow/mlir/pull/141 from bondhugula:splat 48976a6aa0a75be6d91187db6418de989e03eb51
PiperOrigin-RevId: 270965304
This interface will allow for providing hooks to interrop with operation folding. The first hook, 'shouldMaterializeInto', will allow for controlling which region to insert materialized constants into. The folder will generally materialize constants into the top-level isolated region, this allows for materializing into a lower level ancestor region if it is more profitable/correct.
PiperOrigin-RevId: 266702972
All 'getValue' variants now require that the index is valid, queryable via 'isValidIndex'. 'getSplatValue' now requires that the attribute is a proper splat. This allows for querying these methods on DenseElementAttr with all possible value types; e.g. float, int, APInt, etc. This also allows for removing unnecessary conversions to Attribute that really want the underlying value.
PiperOrigin-RevId: 263437337
Change the AsmPrinter to number values breadth-first so that values in adjacent regions can have the same name. This allows for ModuleOp to contain operations that produce results. This also standardizes the special name of region entry arguments to "arg[0-9+]" now that Functions are also operations.
PiperOrigin-RevId: 257225069
This is the standard syntax for types on operations, and is also already used by IntegerAttr and FloatAttr.
Example:
dense<5> : tensor<i32>
dense<[3]> : tensor<1xi32>
PiperOrigin-RevId: 255069157
The OperationFolder currently just inserts into the entry block of a Function, but regions may be isolated above, i.e. explicit capture only, and blindly inserting constants may break the invariants of these regions.
PiperOrigin-RevId: 254987796
This closely mirrors the llvm fcmp instruction, defining 16 different predicates
Constant folding is unsupported for NaN and Inf because there's no way to represent those as constants at the moment
--
PiperOrigin-RevId: 246932358
Note: This now means that we cannot fold chains of operations, i.e. where constant foldable operations feed into each other. Given that this is a testing pass solely for constant folding, this isn't really something that we want anyways. Constant fold tests should be simple and direct, with more advanced folding/feeding being tested with the canonicalizer.
--
PiperOrigin-RevId: 242011744
There are two places containing constant folding logic right now: the ConstantFold
pass and the GreedyPatternRewriteDriver. The logic was not shared and started to
drift apart. We were testing constant folding logic using the ConstantFold pass,
but lagged behind the GreedyPatternRewriteDriver, where we really want the constant
folding to happen.
This CL pulled the logic into utility functions and classes for sharing between
these two places. A new ConstantFoldHelper class is created to help constant fold
and de-duplication.
Also, renamed the ConstantFold pass to TestConstantFold to make it clear that it is
intended for testing purpose.
--
PiperOrigin-RevId: 241971681
The const folding logic is structurally similar, so use a template
to abstract the common part.
Moved mul(x, 0) to a legalization pattern to be consistent with
mul(x, 1).
Also promoted getZeroAttr() to be a method on Builder since it is
expected to be frequently used.
PiperOrigin-RevId: 228891989
This implements the lowering of `floordiv`, `ceildiv` and `mod` operators from
affine expressions to the arithmetic primitive operations. Integer division
rules in affine expressions explicitly require rounding towards either negative
or positive infinity unlike machine implementations that round towards zero.
In the general case, implementing `floordiv` and `ceildiv` using machine signed
division requires computing both the quotient and the remainder. When the
divisor is positive, this can be simplified by adjusting the dividend and the
quotient by one and switching signs.
In the current use cases, we are unlikely to encounter affine expressions with
negative divisors (affine divisions appear in loop transformations such as
tiling that guarantee that divisors are positive by construction). Therefore,
it is reasonable to use branch-free single-division implementation. In case of
affine maps, divisors can only be literals so we can check the sign and
implement the case for negative divisors when the need arises.
The affine lowering pass can still fail when applied to semi-affine maps
(division or modulo by a symbol).
PiperOrigin-RevId: 228668181
Integer comparisons can be constant folded if both of their arguments are known
constants, which we can compare in the compiler. This requires implementing
all comparison predicates, but thanks to consistency between LLVM and MLIR
comparison predicates, we have a one-to-one correspondence between predicates
and llvm::APInt comparison functions. Constant folding of comparsions with
maximum/minimum values of the integer type are left for future work.
This will be used to test the lowering of mod/floordiv/ceildiv in affine
expressions at compile time.
PiperOrigin-RevId: 228077580
This adds signed/unsigned integer division and remainder operations to the
StandardOps dialect. Two versions are required because MLIR integers are
signless, but the meaning of the leading bit is important in division and
affects the results. LLVM IR made a similar choice. Define the operations in
the tablegen file and add simple constant folding hooks in the C++
implementation. Handle signed division overflow and division by zero errors in
constant folding. Canonicalization is left for future work.
These operations are necessary to lower affine_apply's down to LLVM IR.
PiperOrigin-RevId: 228077549
The entire compiler now looks at structural properties of the function (e.g.
does it have one block, does it contain an if/for stmt, etc) so the only thing
holding up this difference is round tripping through the parser/printer syntax.
Removing this shrinks the compile by ~140LOC.
This is step 31/n towards merging instructions and statements. The last step
is updating the docs, which I will do as a separate patch in order to split it
from this mostly mechanical patch.
PiperOrigin-RevId: 227540453
printing the entry block in a CFG function's argument line. Since I'm touching
all of the testcases anyway, change the argument list from printing as
"%arg : type" to "%arg: type" which is more consistent with bb arguments.
In addition to being more consistent, this is a much nicer look for cfg functions.
PiperOrigin-RevId: 227240069
1) affineint (as it is named) is not a type suitable for general computation (e.g. the multiply/adds in an integer matmul). It has undefined width and is undefined on overflow. They are used as the indices for forstmt because they are intended to be used as indexes inside the loop.
2) It can be used in both cfg and ml functions, and in cfg functions. As you mention, “symbols” are not affine, and we use affineint values for symbols.
3) Integers aren’t affine, the algorithms applied to them can be. :)
4) The only suitable use for affineint in MLIR is for indexes and dimension sizes (i.e. the bounds of those indexes).
PiperOrigin-RevId: 216057974
- Fold the lower/upper bound of a loop to a constant whenever the result of the
application of the bound's affine map on the operand list yields a constant.
- Update/complete 'for' stmt's API to set lower/upper bounds with operands.
Resolve TODOs for ForStmt::set{Lower,Upper}Bound.
- Moved AffineExprConstantFolder into AffineMap.cpp and added
AffineMap::constantFold to be used by both AffineApplyOp and
ForStmt::constantFoldBound.
PiperOrigin-RevId: 215997346
optimization pass:
- Give the ability for operations to implement a constantFold hook (a simple
one for single-result ops as well as general support for multi-result ops).
- Implement folding support for constant and addf.
- Implement support in AbstractOperation and Operation to make this usable by
clients.
- Implement a very simple constant folding pass that does top down folding on
CFG and ML functions, with a testcase that exercises all the above stuff.
Random cleanups:
- Improve the build APIs for ConstantOp.
- Stop passing "-o -" to mlir-opt in the testsuite, since that is the default.
PiperOrigin-RevId: 213749809
Uday Bondhugula