[oleksandr-pavlyk]

Move numeric utilities and CPU scan reference functions into dedicated headers for reuse by segmented-scan tests. Update the existing scan and reduce test headers to include them without changing test behavior.

This is preparatory PR with no behavior changes for subsequent change to segmented-scan tests to use cuda buffers

This PR provides a focused subset of changes from #11374

Checklist

• New or existing tests cover these changes.
• The documentation is up to date with these changes.

[coderabbitai]

No actionable comments were generated in the recent review.

Recent review info

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• Source mode: Auto
• Repository: NVIDIA/cccl
• Branch: main
• File: .coderabbit.yaml
• Commit: c6ebc09
• Layers: Repository YAML
• Review profile: CHILL
• Plan: Enterprise
• Run ID: bec4d6ca-d041-4e95-bde4-2c1f57c2fab2

Commits

Reviewing files that changed from the base of the PR and between c6ebc09 and ed4c4f4.

Files selected for processing: 4

• cub/test/catch2_test_device_reduce.cuh
• cub/test/catch2_test_device_scan.cuh
• cub/test/catch2_test_numeric_helpers.cuh
• cub/test/catch2_test_scan_reference.cuh

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📝 Summary

Summary by CodeRabbit

• Tests
  • Updated internal test utilities for numeric operations and scan reference calculations.
  • Test helpers for extended floating-point values, iterator handling, and default-value initialization are now consolidated for reuse.
  • Existing scan and reduction tests continue to use reference calculations; no end-user behavior changes are included in this update.

The change adds dedicated headers for numeric test helpers and scan reference calculations. The reduction and scan test headers include the new headers and remove corresponding local definitions.

Changes: Reusable CUB test helpers

Layer / File(s)	Summary
Numeric helpers and reduction test header cub/test/catch2_test_numeric_helpers.cuh, cub/test/catch2_test_device_reduce.cuh	The new header defines extended-float operations, iterator and operator unwrapping, and default-value initialization. The reduction test header includes it and removes local helper functions, reference calculations, and type declarations.
Scan reference functions cub/test/catch2_test_scan_reference.cuh, cub/test/catch2_test_device_scan.cuh	The new header defines exclusive and inclusive scan reference calculations. The scan test header includes it and removes its local definitions. By-key reference helpers remain in the scan test header.

Possibly related PRs

• NVIDIA/cccl#11374: Its segmented-scan tests use shared type and reference-helper patterns related to the reusable helpers added here.

Suggested reviewers: gonidelis

Priority: Low

Change: Refactor

Merge Risk: Minimal · up to ed4c4

The helper extraction has no substantiated behavior or build regression; it is ready for normal merge checks.

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Finishing Touches: 💡 1

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🥳 CI Workflow Results

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[pauleonix]

Q: Is it correct to keep the old date here? Not sure since the code was only moved and not touched.

[miscco]

I am fine with keeping the old date