Many machine-learning applications (and most software written at AMD)
expect the operation that truncates floats to 8-bit floats to be
saturatinng. That is, they expect `truncf 256.0 : f32 to f8E4M3FNUZ` to
yield `240.0`, not `NaN`, and similarly for negative numbers. However,
the underlying hardware instruction that can be used for this truncation
implements overflow-to-NaN semantics.
To enable handling this usecase, we add the saturate-fp8-truncf option
to ArithToAMDGPU (off by default), which causes the requisite clamping
code to be emitted. Said clamping code ensures that Inf and NaN are
passed through exactly (and thus trancate to NaN).
Per review feedback, this commit efactors
createScalarOrSplatConstant() to the Arith dialect utilities and uses
it in this code. It also fixes naming of existing patterns and
switches from vector.extractelement/insertelement to
vector.extract/insert.
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
Add a new helper function for the type converter that takes care of
casting to the target type.
This is to avoid bugs where an incorrect cast function is used after
type conversion, e.g., `dyn_cast` or `cast`. These are not guaranteed to
work when type conversion fails, or when type conversion succeeds but
the provided type converted returned a type that a conversion pattern
did not expect.
I saw this being an issue in some SPIR-V passes and in mlir-hlo.
Exercise the new function in a couple of passes. As a side-effect, this
also made the code more concise.
Reviewed By: rriddle, mehdi_amini
Differential Revision: https://reviews.llvm.org/D148725
This includes standard LIT tests and integration tests with the LLVM CPU
runner.
I plan to use this to implement `sitofp` in D146597.
Reviewed By: antiagainst
Differential Revision: https://reviews.llvm.org/D146606
Using `arith.mului_extended` makes it much simpler to emulate wide
integer multiplication.
Reviewed By: antiagainst
Differential Revision: https://reviews.llvm.org/D139776
The goal is to make the naming of the future `_extended` ops more
consistent. With unsigned addition, the carry value/flag and overflow
bit are the same, but this is not true when it comes to signed addition.
Also rename the second result from `carry` to `overflow`.
Reviewed By: antiagainst
Differential Revision: https://reviews.llvm.org/D139569
This patch mechanically replaces None with std::nullopt where the
compiler would warn if None were deprecated. The intent is to reduce
the amount of manual work required in migrating from Optional to
std::optional.
This is part of an effort to migrate from llvm::Optional to
std::optional:
https://discourse.llvm.org/t/deprecating-llvm-optional-x-hasvalue-getvalue-getvalueor/63716
Add a new pass and conversions to emulate wide integer operations over memrefs.
The emulation is implemented on top of the existing pass to emulate wide integer arith ops.
Improve naming in the arith pass to avoid potential name clashes.
Reviewed By: antiagainst
Differential Revision: https://reviews.llvm.org/D135722
Print unsupported types on match failures.
Suggested by @Mogball and @jpienaar in D135204.
Reviewed By: Mogball
Differential Revision: https://reviews.llvm.org/D135673
