See https://github.com/llvm/llvm-project/pull/147168 for more info.

These are identified by misc-include-cleaner.  I've filtered out those
that break builds.  Also, I'm staying away from llvm-config.h,
config.h, and Compiler.h, which likely cause platform- or
compiler-specific build failures.

See https://github.com/llvm/llvm-project/pull/147168 for more info.

Also fix some typos in comments

---------

Co-authored-by: Mehdi Amini <joker.eph@gmail.com>

This PR fixes a bug in `MathToFuncs` where it incorrectly converts index
type for `math.ctlz` and `math.ipowi`, leading to a crash. Fixes
#108150.

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

This fixes issues caused by D146261.
Differential Revision: https://reviews.llvm.org/D148477

This change adds a software implementation of the `math.ctlz` operation
and includes it in `--convert-math-to-funcs`.

This is my first change to MLIR, so please bear with me as I'm still learning
the idioms of the codebase.

The context for this change is that I have some larger scale project in which
I'd like to lower from a mix of MLIR dialects to CIRCT, but many of the CIRCT
passes don't support the `math` dialect.

I noticed the content of `convert-math-to-funcs` was limited entirely to
the `pow` functions, but otherwise provided the needed structure to implement
this feature with minimal changes.

Highlight of the changes:

- Add a dependence on the SCF dialect for this lower. I could have lowered
  directly to cf, following the pow lowerings in the same pass, but I felt it
  was not necessary given the existing support for lowering scf to cf.
- Generalize the DenseMap storing op implementations: modify the callback
  function hashmap to be keyed by both OperationType (for me this effectively
  means the name of the op being implemented in software) and the type
  signature of the resulting function.
- Implement the ctlz function as a loop. I had researched a variety of
  implementations that claimed to be more efficient (such as those based on a
  de Bruijn sequence), but it seems to me that the simplest approach would make
  it easier for later compiler optimizations to do a better (platform-aware)
  job optimizing this than I could do by hand.

Questions I had for the reviewer:

- [edit: found mlir-cpu-runner and added two tests] What would I add to the filecheck invocation to actually run the resulting MLIR on a value and assert the output is correct? I have done this manually with the C implementation but I'm not confident my port to MLIR is correct.
- Should I add a test for a vectorized version of this lowering? I followed suit with the ` VecOpToScalarOp` but I admit I don't fully understand what it's doing.

Reviewed By: vzakhari

Differential Revision: https://reviews.llvm.org/D146261

Differential Revision: https://reviews.llvm.org/D145784