The polynomial approximation for asin is only good between [-9/16,
9/16]. Values beyond that range must be remapped to achieve good numeric
results. This is done by the equation below:
`arcsin(x) = PI/2 - arcsin(sqrt(1.0 - x*x))`
This simply updates the rewrites to propagate the scalable flags (which
as they do not alter the vector shape, is pretty simple).
The added tests are simply scalable versions of the existing vector
tests.
These patterns can already be used via
populateMathPolynomialApproximationPatterns, but that includes a number
of other patterns that may not be needed.
There are already similar functions for expansion.
For now only adding tanh and erf since I have a concrete use case for
these two.
Used the cephes numerical approximation for `math.atan`. This is a
significant accuracy improvement over the previous taylor series
approximation.
Reviewed By: jpienaar
Differential Revision: https://reviews.llvm.org/D153656
The existing lowering has lower precision for certain use cases, e.g.
tanh. Improved version should demonstrate an overall higher level of precision.
Reviewed By: cota, jpienaar
Differential Revision: https://reviews.llvm.org/D153592
The MLIR classes Type/Attribute/Operation/Op/Value support
cast/dyn_cast/isa/dyn_cast_or_null functionality through llvm's doCast
functionality in addition to defining methods with the same name.
This change begins the migration of uses of the method to the
corresponding function call as has been decided as more consistent.
Note that there still exist classes that only define methods directly,
such as AffineExpr, and this does not include work currently to support
a functional cast/isa call.
Caveats include:
- This clang-tidy script probably has more problems.
- This only touches C++ code, so nothing that is being generated.
Context:
- https://mlir.llvm.org/deprecation/ at "Use the free function variants
for dyn_cast/cast/isa/…"
- Original discussion at https://discourse.llvm.org/t/preferred-casting-style-going-forward/68443
Implementation:
This first patch was created with the following steps. The intention is
to only do automated changes at first, so I waste less time if it's
reverted, and so the first mass change is more clear as an example to
other teams that will need to follow similar steps.
Steps are described per line, as comments are removed by git:
0. Retrieve the change from the following to build clang-tidy with an
additional check:
https://github.com/llvm/llvm-project/compare/main...tpopp:llvm-project:tidy-cast-check
1. Build clang-tidy
2. Run clang-tidy over your entire codebase while disabling all checks
and enabling the one relevant one. Run on all header files also.
3. Delete .inc files that were also modified, so the next build rebuilds
them to a pure state.
4. Some changes have been deleted for the following reasons:
- Some files had a variable also named cast
- Some files had not included a header file that defines the cast
functions
- Some files are definitions of the classes that have the casting
methods, so the code still refers to the method instead of the
function without adding a prefix or removing the method declaration
at the same time.
```
ninja -C $BUILD_DIR clang-tidy
run-clang-tidy -clang-tidy-binary=$BUILD_DIR/bin/clang-tidy -checks='-*,misc-cast-functions'\
-header-filter=mlir/ mlir/* -fix
rm -rf $BUILD_DIR/tools/mlir/**/*.inc
git restore mlir/lib/IR mlir/lib/Dialect/DLTI/DLTI.cpp\
mlir/lib/Dialect/Complex/IR/ComplexDialect.cpp\
mlir/lib/**/IR/\
mlir/lib/Dialect/SparseTensor/Transforms/SparseVectorization.cpp\
mlir/lib/Dialect/Vector/Transforms/LowerVectorMultiReduction.cpp\
mlir/test/lib/Dialect/Test/TestTypes.cpp\
mlir/test/lib/Dialect/Transform/TestTransformDialectExtension.cpp\
mlir/test/lib/Dialect/Test/TestAttributes.cpp\
mlir/unittests/TableGen/EnumsGenTest.cpp\
mlir/test/python/lib/PythonTestCAPI.cpp\
mlir/include/mlir/IR/
```
Differential Revision: https://reviews.llvm.org/D150123
Currently conversions to interfaces may happen implicitly (e.g.
`Attribute -> TypedAttr`), failing a runtime assert if the interface
isn't actually implemented. This change marks the `Interface(ValueT)`
constructor as explicit so that a cast is required.
Where it was straightforward to I adjusted code to not require casts,
otherwise I just made them explicit.
Depends on D148491, D148492
Reviewed By: rriddle
Differential Revision: https://reviews.llvm.org/D148493
Polynomial approximations assume F32 values. We can convert all non-f32
cases to operate on f32s with intermediate casts.
Reviewed By: jpienaar
Differential Revision: https://reviews.llvm.org/D146677
Cbrt can be approximated with some relatively simple polynomial
operators. This includes a lit test validating the implementation
and some run tests that validate numerical correct.
Reviewed By: jpienaar
Differential Revision: https://reviews.llvm.org/D145019
This revision refactors and cleans up a bunch of infra related to vector, shapes and indexing into more reusable APIs.
Differential Revision: https://reviews.llvm.org/D138501
This patch fixes:
mlir/lib/Dialect/Math/Transforms/PolynomialApproximation.cpp:171:30:
warning: suggest parentheses around ‘&&’ within ‘||’ [-Wparentheses]
mlir/lib/Dialect/Math/Transforms/PolynomialApproximation.cpp:283:30:
warning: suggest parentheses around ‘&&’ within ‘||’ [-Wparentheses]
Previously, NaNs would be dropped in favor of bounded values which was
strictly incorrect. Now the min/max operation propagate this
information. Not all uses of min/max need this, but the given change
will help protect future additions, and this prevents the need for an
additional cmpf and select operation to handle NaNs.
Differential Revision: https://reviews.llvm.org/D120020
Reuse the higher precision F32 approximation for the F16 one (by expanding and
truncating). This is partly RFC as I'm not sure what the expectations are here
(e.g., these are only for F32 and should not be expanded, that reusing
higher-precision ones for lower precision is undesirable due to increased
compute cost and only approximations per exact type is preferred, or this is
appropriate [at least as fallback] but we need to see how to make it more
generic across all the patterns here).
Differential Revision: https://reviews.llvm.org/D118968
This is completely unused upstream, and does not really have well defined semantics
on what this is supposed to do/how this fits into the ecosystem. Given that, as part of
splitting up the standard dialect it's best to just remove this behavior, instead of try
to awkwardly fit it somewhere upstream. Downstream users are encouraged to
define their own operations that clearly can define the semantics of this.
This also uncovered several lingering uses of ConstantOp that weren't
updated to use arith::ConstantOp, and worked during conversions because
the constant was removed/converted into something else before
verification.
See https://llvm.discourse.group/t/standard-dialect-the-final-chapter/ for more discussion.
Differential Revision: https://reviews.llvm.org/D118654
This reduces the dependencies of the MLIRVector target and makes the dialect consistent with other dialects.
Differential Revision: https://reviews.llvm.org/D118533
Implement a taylor series approximation for atan and add an atan2 lowering
that uses atan's appromation. This includes tests for edge cases and tests
for each quadrant.
Reviewed By: NatashaKnk
Differential Revision: https://reviews.llvm.org/D115682
Using [1] for representing shape of a scalar is incorrect, and will break with vectors of size 1.
- remove redundant helper functions
- fix couple of style warnings
Reviewed By: cota
Differential Revision: https://reviews.llvm.org/D112764
Polynomial approximation can be extented to support N-d vectors.
N-dimensional vectors are useful when vectorizing operations on N-dimensional
tiles. Before lowering to LLVM these vectors are usually unrolled or flattened
to 1-dimensional vectors.
Differential Revision: https://reviews.llvm.org/D112566
This patch adds a polynomial approximation that matches the
approximation in Eigen.
Note that the approximation only applies to vectorized inputs;
the scalar rsqrt is left unmodified.
The approximation is protected with a flag since it emits an AVX2
intrinsic (generated via the X86Vector). This is the only reasonably
clean way that I could find to generate the exact approximation that
I wanted (i.e. an identical one to Eigen's).
I considered two alternatives:
1. Introduce a Rsqrt intrinsic in LLVM, which doesn't exist yet.
I believe this is because there is no definition of Rsqrt that
all backends could agree on, since hardware instructions that
implement it have widely varying degrees of precision.
This is something that the standard could mandate, but Rsqrt is
not part of IEEE754, so I don't think this option is feasible.
2. Emit fdiv(1.0, sqrt) with fast math flags to allow reciprocal
transformations. Although portable, this doesn't allow us
to generate exactly the code we want; it is the LLVM backend,
and not MLIR, who controls what code is generated based on the
target CPU.
Reviewed By: ezhulenev
Differential Revision: https://reviews.llvm.org/D112192
Use wider range for approximating Tanh to match results computed in Eigen with AVX.
Reviewed By: cota
Differential Revision: https://reviews.llvm.org/D112011
Precursor: https://reviews.llvm.org/D110200
Removed redundant ops from the standard dialect that were moved to the
`arith` or `math` dialects.
Renamed all instances of operations in the codebase and in tests.
Reviewed By: rriddle, jpienaar
Differential Revision: https://reviews.llvm.org/D110797
This is a bit cleaner and removes issues with 2d vectors. It also has a
big impact on constant folding, hence the test changes.
Differential Revision: https://reviews.llvm.org/D107896
The approximation relays on range reduced version y \in [0, pi/2]. An input x will have
the property that sin(x) = sin(y), -sin(y), cos(y), -cos(y) depends on which quadrable x
is in, where sin(y) and cos(y) are approximated with 5th degree polynomial (of x^2).
As a result a single pattern can be used to compute approximation for both sine and cosine.
Reviewed By: ezhulenev
Differential Revision: https://reviews.llvm.org/D104582
