[oleksandr-pavlyk]

Description

Add overloads to catch2_test_numeric_helpers.cuh and add tests in a new catch2_test_numeric_helpers.cu test file.

closes #12585

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.

Summary

Summary by CodeRabbit

• Tests
  • Expanded numeric iterator coverage for standard integers and supported half-precision types.
  • Added checks that pointer unwrapping preserves pointer type, address, constness, and null values.
  • Added checks that constant-iterator unwrapping preserves values and offset types.

The change adds const-pointer unwrap_it overloads for half and bfloat16 wrappers. Tests check pointer conversions, null pointers, and constant-iterator values and offset types.

Changes: unwrap_it const-pointer support

Layer / File(s)	Summary
Half and bfloat16 const-pointer overloads cub/test/catch2_test_numeric_helpers.cuh	Added overloads that convert const half_t* to const __half* and const bfloat16_t* to const __nv_bfloat16*. The constant-iterator overloads now bind the wrapped and converted values as const.
Pointer and constant-iterator tests cub/test/catch2_test_numeric_helpers.cu	Added tests for pointer type, address, constness, and null preservation. Constant-iterator tests check unwrapped values and offset types across configured types.

Assessment against linked issues

Objective	Addressed	Explanation
Add unwrap_it const-pointer overloads for half-precision wrapper types [#12585]	✅

Possibly related PRs

• NVIDIA/cccl#11374: Adds the original unwrap_it conversions for half and bfloat16 pointers and constant iterators.
• NVIDIA/cccl#12260: Extracts the numeric helper header that contains the unwrap_it overloads.

Change: Feature · Severity of issue fixed: Medium

Merge Risk: Minimal · up to ddeeb

The pointer conversions and their tests have no identified merge-blocking issue.

Architecture risk: Low · up to ddeeb

The change affects 1 system.

Changed systems: cub

Architecture concerns
No architecture-level concerns identified.

Review details

Systems and components

• observed — cub (service) was modified; 2 changed files map to changed impact.

Before / after behavior

• observed — Modified behavior in cub/test/catch2_test_numeric_helpers.cu: Adds wrapped/unwrapped type pairs for int32_t and, when enabled by the test macros, half and bfloat16 types.
• observed — Modified behavior in cub/test/catch2_test_numeric_helpers.cu: Adds pointer tests asserting that unwrap_it returns the corresponding unwrapped pointer type, preserves addresses and constness, and returns null for null pointers.
• observed — Modified behavior in cub/test/catch2_test_numeric_helpers.cu: Adds constant-iterator tests across the configured wrapped types and int32_t/int64_t offsets, asserting the unwrapped iterator type retains its offset type and yields the original value at its base and offset positions.
• observed — Modified behavior in cub/test/catch2_test_numeric_helpers.cuh: Added const-pointer unwrap_it overloads for half_t and bfloat16_t, returning pointers to the corresponding const CUDA types.

- [ ] Autofix · Keep fixing CodeRabbit findings and required CI, and resolving merge conflicts

Recent review info

Run configuration

• Source mode: Auto
• Repository: NVIDIA/cccl
• Branch: main
• File: .coderabbit.yaml
• Commit: 878f124
• Layers: Repository YAML
• Review profile: CHILL
• Plan: Enterprise
• Run ID: 97fbf363-2aa0-4c35-9ffa-98dc57705fb7

Commits

Reviewing files that changed from the base of the PR and between 93ab9ca and ddeeb0c.

Files selected for processing: 1

• cub/test/catch2_test_numeric_helpers.cuh

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