[AIROCMLIR-390] clang-format: break .td DAG operands onto separate lines

[bogdan-petkovic]

Motivation

Resolves #1936.
Recent versions of git-clang-format include .td (TableGen) files in their default extension list. The repo's .clang-format only sets BasedOnStyle: LLVM, which uses TableGen defaults that pack multiple DAG operands onto a single line.
The result is hard to read; e.g. before this PR, commonConvArgs in mlir/include/mlir/Dialect/Rock/IR/RockOps.td looked like:

dag commonConvArgs = (ins TensorOrMemRefOf:$filter, TensorOrMemRefOf:$input, TensorOrMemRefOf:$output, OptionalAttr<Rock_GemmFeaturesAttr>:$features, OptionalAttr:$derivedBlockSize, OptionalAttr:$gridSize, IndexArrayLength<4>:$padding, IndexArrayLength<2>:$strides, ...

The goal of this PR is to make git clang-format origin/develop produce one operand per line for (ins ...) / (outs ...) DAGs.

Technical Details

Configuration changes:

• .clang-format and mlir/.clang-format: add two clang-format options introduced in clang-format 19:
  • TableGenBreakInsideDAGArg: BreakElements — break after each DAG element, aligned to the first element.
  • TableGenBreakingDAGArgOperators: [ins, outs] — restrict the breaking behavior to DAGs starting with ins or outs, so unrelated DAG expressions are not reflowed.
• .githooks/pre-commit: extend the staged-file regex to include .td, so staged TableGen changes get formatted at commit time alongside C/C++.
• CONTRIBUTING.md: note that clang-format >= 19 is now required for this repo (CI is already on LLVM 20 via mlir/utils/jenkins/Dockerfile). Mention that .td files are covered by git clang-format origin/develop.

NFC follow-up commit:

• Bulk reformat of all 13 .td files under mlir/ that contain (ins ...) / (outs ...) DAGs, using clang-format-20 -i. Pure formatting, no semantic changes. The commit SHA is added to .git-blame-ignore-revs so git blame skips it, in line with the existing entries in that file.

Test Plan

Verified locally with clang-format-20 / git-clang-format-20:

1. Both updated .clang-format files parse with clang-format 20.
2. Idempotency: re-running clang-format-20 -i on every reformatted .td file produces no further changes.
3. CI-equivalent gate: git-clang-format-20 --binary clang-format-20 --diff origin/develop returns "clang-format did not modify any files".
4. commonConvArgs in RockOps.td now matches the layout requested in the issue exactly (one operand per line, aligned after (ins ).

Test Result

• PR CI
• Nightly CI
• Weekly CI

Submission Checklist

• Look over the contributing guidelines at https://github.com/ROCm/ROCm/blob/develop/CONTRIBUTING.md#pull-requests.

[codecov]

Codecov Report

✅ All modified and coverable lines are covered by tests.

Additional details and impacted files

@@             Coverage Diff             @@
##           develop    #2377      +/-   ##
===========================================
+ Coverage    79.50%   81.53%   +2.03%     
===========================================
  Files          100      125      +25     
  Lines        31016    42344   +11328     
  Branches      4819     6985    +2166     
===========================================
+ Hits         24659    34524    +9865     
- Misses        4245     5194     +949     
- Partials      2112     2626     +514     

Flag	Coverage Δ
mfma	81.34% <ø> (+1.84%)	⬆️
navi4x	81.48% <ø> (?)

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see 111 files with indirect coverage changes

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[Copilot]

Pull request overview

Enables clang-format's TableGen DAG-breaking options so (ins …)/(outs …) operands lay out one-per-line, wires .td files into the pre-commit hook, documents the new clang-format >= 19 requirement, and bulk-reformats 13 .td files under mlir/ (with the reformat SHA added to .git-blame-ignore-revs).

Changes:

• Add TableGenBreakInsideDAGArg: BreakElements and TableGenBreakingDAGArgOperators: [ins, outs] to both .clang-format files; extend pre-commit hook to .td; update CONTRIBUTING.md.
• Append the bulk-reformat commit to .git-blame-ignore-revs.
• Apply clang-format-20 -i to 13 .td files (NFC).

Reviewed changes

Copilot reviewed 18 out of 18 changed files in this pull request and generated 5 comments.

Show a summary per file

File	Description
.clang-format	Adds TableGen DAG-break options
mlir/.clang-format	Same TableGen DAG-break options
.githooks/pre-commit	Includes .td in staged file regex
CONTRIBUTING.md	Documents clang-format >= 19 requirement and .td coverage
.git-blame-ignore-revs	Adds NFC reformat commit
mlir/include/mlir/Conversion/RocMLIRPasses.td	Reformatted dependentDialects/options
mlir/include/mlir/Dialect/MIGraphX/Passes.td	Reformatted; file header banner split across lines
mlir/include/mlir/Dialect/MIGraphX/IR/MIGraphX.td	Reformatted op defs; header banner split
mlir/include/mlir/Dialect/MIGraphX/IR/MIGraphXBase.td	License comment reflow
mlir/include/mlir/Dialect/MIGraphX/IR/MIGraphXTypes.td	Reformatted; header banner split
mlir/include/mlir/Dialect/Rock/Passes.td	Reformatted pass defs
mlir/include/mlir/Dialect/Rock/IR/RockOps.td	Bulk DAG-arg reflow
mlir/include/mlir/Dialect/Rock/IR/RockAttrDefs.td	Reformatted; header banner split
mlir/include/mlir/Dialect/Rock/IR/RockAcceptingViewOpInterface.td	Header banner split
mlir/include/mlir/Dialect/Rock/IR/RockAccelTuningParamAttrInterface.td	Class decl reflow
mlir/include/mlir/Dialect/Rock/IR/RockGemmWrapperInterface.td	License comment reflow
mlir/include/mlir/Dialect/Rock/IR/RockTuningParamAttrInterface.td	Reflow + blank-line cleanups
mlir/include/mlir/Dialect/Rock/IR/RockWriterOpInterface.td	License comment reflow

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