fixes merge conflict for policy pruning

[elstehle]

Description

#2154 still was using the _LIBCUDACXX_UNREACHABLE that, since the PR's last CI run, was updated to _CCCL_UNREACHABLE after #2399 was merged. _LIBCUDACXX_UNREACHABLE should be replaced with _CCCL_UNREACHABLE. This PR fixes that.

Checklist

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

[github-actions]

🟩 CI finished in 1h 27m: Pass: 100%/208 | Total: 5d 12h | Avg: 38m 19s | Max: 1h 06m | Hits: 65%/14058

• 🟩 cub: Pass: 100%/104 | Total: 3d 09h | Avg: 46m 48s | Max: 1h 06m | Hits: 41%/2908

  🟩 cpu
    🟩 amd64              Pass: 100%/96  | Total:  3d 02h | Avg: 46m 19s | Max:  1h 06m | Hits:  41%/2908  
    🟩 arm64              Pass: 100%/8   | Total:  7h 00m | Avg: 52m 35s | Max: 54m 02s
  🟩 ctk
    🟩 11.1               Pass: 100%/15  | Total: 11h 11m | Avg: 44m 46s | Max: 54m 52s | Hits:  41%/727   
    🟩 11.8               Pass: 100%/3   | Total:  3h 15m | Avg:  1h 05m | Max:  1h 06m
    🟩 12.6               Pass: 100%/86  | Total:  2d 18h | Avg: 46m 31s | Max:  1h 02m | Hits:  41%/2181  
  🟩 cudacxx
    🟩 ClangCUDA18        Pass: 100%/2   | Total:  1h 47m | Avg: 53m 49s | Max: 53m 56s
    🟩 nvcc11.1           Pass: 100%/15  | Total: 11h 11m | Avg: 44m 46s | Max: 54m 52s | Hits:  41%/727   
    🟩 nvcc11.8           Pass: 100%/3   | Total:  3h 15m | Avg:  1h 05m | Max:  1h 06m
    🟩 nvcc12.6           Pass: 100%/84  | Total:  2d 16h | Avg: 46m 20s | Max:  1h 02m | Hits:  41%/2181  
  🟩 cudacxx_family
    🟩 ClangCUDA          Pass: 100%/2   | Total:  1h 47m | Avg: 53m 49s | Max: 53m 56s
    🟩 nvcc               Pass: 100%/102 | Total:  3d 07h | Avg: 46m 40s | Max:  1h 06m | Hits:  41%/2908  
  🟩 cxx
    🟩 Clang9             Pass: 100%/6   | Total:  4h 49m | Avg: 48m 19s | Max: 56m 01s
    🟩 Clang10            Pass: 100%/3   | Total:  2h 29m | Avg: 49m 55s | Max: 51m 05s
    🟩 Clang11            Pass: 100%/4   | Total:  3h 15m | Avg: 48m 52s | Max: 49m 15s
    🟩 Clang12            Pass: 100%/4   | Total:  3h 16m | Avg: 49m 08s | Max: 49m 25s
    🟩 Clang13            Pass: 100%/4   | Total:  3h 15m | Avg: 48m 51s | Max: 49m 00s
    🟩 Clang14            Pass: 100%/4   | Total:  3h 14m | Avg: 48m 39s | Max: 48m 59s
    🟩 Clang15            Pass: 100%/4   | Total:  3h 14m | Avg: 48m 44s | Max: 48m 52s
    🟩 Clang16            Pass: 100%/4   | Total:  3h 17m | Avg: 49m 17s | Max: 49m 24s
    🟩 Clang17            Pass: 100%/4   | Total:  3h 21m | Avg: 50m 23s | Max: 55m 46s
    🟩 Clang18            Pass: 100%/9   | Total:  6h 44m | Avg: 44m 57s | Max: 53m 56s
    🟩 GCC6               Pass: 100%/2   | Total:  1h 25m | Avg: 42m 32s | Max: 42m 55s
    🟩 GCC7               Pass: 100%/6   | Total:  4h 42m | Avg: 47m 05s | Max: 54m 29s
    🟩 GCC8               Pass: 100%/6   | Total:  4h 44m | Avg: 47m 29s | Max: 49m 10s
    🟩 GCC9               Pass: 100%/6   | Total:  4h 45m | Avg: 47m 38s | Max: 56m 29s
    🟩 GCC10              Pass: 100%/4   | Total:  3h 18m | Avg: 49m 43s | Max: 50m 11s
    🟩 GCC11              Pass: 100%/7   | Total:  6h 37m | Avg: 56m 44s | Max:  1h 06m
    🟩 GCC12              Pass: 100%/4   | Total:  3h 22m | Avg: 50m 36s | Max: 53m 21s
    🟩 GCC13              Pass: 100%/16  | Total:  8h 36m | Avg: 32m 17s | Max: 56m 42s
    🟩 Intel2023.2.0      Pass: 100%/3   | Total:  2h 37m | Avg: 52m 29s | Max: 53m 19s
    🟩 MSVC14.16          Pass: 100%/1   | Total: 54m 52s | Avg: 54m 52s | Max: 54m 52s | Hits:  41%/727   
    🟩 MSVC14.29          Pass: 100%/2   | Total:  1h 59m | Avg: 59m 50s | Max: 59m 53s | Hits:  41%/1454  
    🟩 MSVC14.39          Pass: 100%/1   | Total:  1h 02m | Avg:  1h 02m | Max:  1h 02m | Hits:  41%/727   
  🟩 cxx_family
    🟩 Clang              Pass: 100%/46  | Total:  1d 13h | Avg: 48m 15s | Max: 56m 01s
    🟩 GCC                Pass: 100%/51  | Total:  1d 13h | Avg: 44m 11s | Max:  1h 06m
    🟩 Intel              Pass: 100%/3   | Total:  2h 37m | Avg: 52m 29s | Max: 53m 19s
    🟩 MSVC               Pass: 100%/4   | Total:  3h 56m | Avg: 59m 11s | Max:  1h 02m | Hits:  41%/2908  
  🟩 gpu
    🟩 v100               Pass: 100%/104 | Total:  3d 09h | Avg: 46m 48s | Max:  1h 06m | Hits:  41%/2908  
  🟩 jobs
    🟩 Build              Pass: 100%/96  | Total:  3d 06h | Avg: 49m 08s | Max:  1h 06m | Hits:  41%/2908  
    🟩 DeviceLaunch       Pass: 100%/1   | Total: 16m 04s | Avg: 16m 04s | Max: 16m 04s
    🟩 GraphCapture       Pass: 100%/1   | Total: 14m 53s | Avg: 14m 53s | Max: 14m 53s
    🟩 HostLaunch         Pass: 100%/3   | Total: 48m 49s | Avg: 16m 16s | Max: 17m 45s
    🟩 TestGPU            Pass: 100%/3   | Total:  1h 10m | Avg: 23m 38s | Max: 25m 35s
  🟩 sm
    🟩 60;70;80;90        Pass: 100%/3   | Total:  3h 15m | Avg:  1h 05m | Max:  1h 06m
    🟩 90a                Pass: 100%/4   | Total:  1h 24m | Avg: 21m 13s | Max: 22m 12s
  🟩 std
    🟩 11                 Pass: 100%/28  | Total: 21h 29m | Avg: 46m 02s | Max:  1h 04m
    🟩 14                 Pass: 100%/27  | Total: 22h 24m | Avg: 49m 48s | Max:  1h 04m | Hits:  41%/1454  
    🟩 17                 Pass: 100%/26  | Total: 21h 19m | Avg: 49m 12s | Max:  1h 06m | Hits:  41%/727   
    🟩 20                 Pass: 100%/23  | Total: 15h 54m | Avg: 41m 30s | Max:  1h 02m | Hits:  41%/727   
  

• 🟩 thrust: Pass: 100%/103 | Total: 2d 03h | Avg: 29m 58s | Max: 59m 47s | Hits: 71%/11150

  🟩 cpu
    🟩 amd64              Pass: 100%/95  | Total:  1d 23h | Avg: 30m 01s | Max: 59m 47s | Hits:  71%/11150 
    🟩 arm64              Pass: 100%/8   | Total:  3h 54m | Avg: 29m 18s | Max: 33m 11s
  🟩 ctk
    🟩 11.1               Pass: 100%/15  | Total:  7h 16m | Avg: 29m 07s | Max: 55m 21s | Hits:  65%/2230  
    🟩 11.8               Pass: 100%/3   | Total:  2h 02m | Avg: 40m 59s | Max: 46m 21s
    🟩 12.6               Pass: 100%/85  | Total:  1d 18h | Avg: 29m 44s | Max: 59m 47s | Hits:  73%/8920  
  🟩 cudacxx
    🟩 ClangCUDA18        Pass: 100%/2   | Total: 53m 36s | Avg: 26m 48s | Max: 28m 40s
    🟩 nvcc11.1           Pass: 100%/15  | Total:  7h 16m | Avg: 29m 07s | Max: 55m 21s | Hits:  65%/2230  
    🟩 nvcc11.8           Pass: 100%/3   | Total:  2h 02m | Avg: 40m 59s | Max: 46m 21s
    🟩 nvcc12.6           Pass: 100%/83  | Total:  1d 17h | Avg: 29m 48s | Max: 59m 47s | Hits:  73%/8920  
  🟩 cudacxx_family
    🟩 ClangCUDA          Pass: 100%/2   | Total: 53m 36s | Avg: 26m 48s | Max: 28m 40s
    🟩 nvcc               Pass: 100%/101 | Total:  2d 02h | Avg: 30m 02s | Max: 59m 47s | Hits:  71%/11150 
  🟩 cxx
    🟩 Clang9             Pass: 100%/6   | Total:  2h 49m | Avg: 28m 15s | Max: 32m 48s
    🟩 Clang10            Pass: 100%/3   | Total:  1h 30m | Avg: 30m 14s | Max: 32m 59s
    🟩 Clang11            Pass: 100%/4   | Total:  1h 56m | Avg: 29m 09s | Max: 31m 08s
    🟩 Clang12            Pass: 100%/4   | Total:  1h 59m | Avg: 29m 48s | Max: 31m 38s
    🟩 Clang13            Pass: 100%/4   | Total:  1h 56m | Avg: 29m 13s | Max: 31m 12s
    🟩 Clang14            Pass: 100%/4   | Total:  1h 59m | Avg: 29m 48s | Max: 31m 40s
    🟩 Clang15            Pass: 100%/4   | Total:  1h 58m | Avg: 29m 35s | Max: 32m 13s
    🟩 Clang16            Pass: 100%/4   | Total:  1h 58m | Avg: 29m 35s | Max: 32m 19s
    🟩 Clang17            Pass: 100%/4   | Total:  1h 58m | Avg: 29m 42s | Max: 32m 37s
    🟩 Clang18            Pass: 100%/9   | Total:  4h 01m | Avg: 26m 50s | Max: 35m 28s
    🟩 GCC6               Pass: 100%/2   | Total: 53m 20s | Avg: 26m 40s | Max: 28m 47s
    🟩 GCC7               Pass: 100%/6   | Total:  2h 54m | Avg: 29m 06s | Max: 35m 46s
    🟩 GCC8               Pass: 100%/6   | Total:  2h 51m | Avg: 28m 31s | Max: 31m 58s
    🟩 GCC9               Pass: 100%/6   | Total:  2h 56m | Avg: 29m 25s | Max: 33m 37s
    🟩 GCC10              Pass: 100%/4   | Total:  2h 08m | Avg: 32m 12s | Max: 38m 55s
    🟩 GCC11              Pass: 100%/7   | Total:  4h 16m | Avg: 36m 36s | Max: 46m 21s
    🟩 GCC12              Pass: 100%/4   | Total:  2h 07m | Avg: 31m 48s | Max: 34m 37s
    🟩 GCC13              Pass: 100%/14  | Total:  5h 10m | Avg: 22m 12s | Max: 34m 28s
    🟩 Intel2023.2.0      Pass: 100%/3   | Total:  1h 50m | Avg: 36m 53s | Max: 40m 54s
    🟩 MSVC14.16          Pass: 100%/1   | Total: 55m 21s | Avg: 55m 21s | Max: 55m 21s | Hits:  65%/2230  
    🟩 MSVC14.29          Pass: 100%/2   | Total:  1h 50m | Avg: 55m 16s | Max: 55m 59s | Hits:  65%/4460  
    🟩 MSVC14.39          Pass: 100%/2   | Total:  1h 22m | Avg: 41m 23s | Max: 59m 47s | Hits:  82%/4460  
  🟩 cxx_family
    🟩 Clang              Pass: 100%/46  | Total: 22h 09m | Avg: 28m 53s | Max: 35m 28s
    🟩 GCC                Pass: 100%/49  | Total: 23h 18m | Avg: 28m 32s | Max: 46m 21s
    🟩 Intel              Pass: 100%/3   | Total:  1h 50m | Avg: 36m 53s | Max: 40m 54s
    🟩 MSVC               Pass: 100%/5   | Total:  4h 08m | Avg: 49m 44s | Max: 59m 47s | Hits:  71%/11150 
  🟩 gpu
    🟩 v100               Pass: 100%/103 | Total:  2d 03h | Avg: 29m 58s | Max: 59m 47s | Hits:  71%/11150 
  🟩 jobs
    🟩 Build              Pass: 100%/96  | Total:  2d 01h | Avg: 30m 54s | Max: 59m 47s | Hits:  65%/8920  
    🟩 TestCPU            Pass: 100%/4   | Total: 44m 29s | Avg: 11m 07s | Max: 23m 00s | Hits:  99%/2230  
    🟩 TestGPU            Pass: 100%/3   | Total:  1h 16m | Avg: 25m 32s | Max: 35m 28s
  🟩 sm
    🟩 60;70;80;90        Pass: 100%/3   | Total:  2h 02m | Avg: 40m 59s | Max: 46m 21s
    🟩 90a                Pass: 100%/4   | Total:  1h 09m | Avg: 17m 25s | Max: 19m 06s
  🟩 std
    🟩 11                 Pass: 100%/28  | Total: 11h 26m | Avg: 24m 30s | Max: 32m 19s
    🟩 14                 Pass: 100%/27  | Total: 14h 36m | Avg: 32m 26s | Max: 55m 21s | Hits:  65%/4460  
    🟩 17                 Pass: 100%/26  | Total: 14h 20m | Avg: 33m 06s | Max: 55m 59s | Hits:  65%/2230  
    🟩 20                 Pass: 100%/22  | Total: 11h 04m | Avg: 30m 12s | Max: 59m 47s | Hits:  82%/4460  
  

• 🟩 pycuda: Pass: 100%/1 | Total: 14m 47s | Avg: 14m 47s | Max: 14m 47s

  🟩 cpu
    🟩 amd64              Pass: 100%/1   | Total: 14m 47s | Avg: 14m 47s | Max: 14m 47s
  🟩 ctk
    🟩 12.5               Pass: 100%/1   | Total: 14m 47s | Avg: 14m 47s | Max: 14m 47s
  🟩 cudacxx
    🟩 nvcc12.5           Pass: 100%/1   | Total: 14m 47s | Avg: 14m 47s | Max: 14m 47s
  🟩 cudacxx_family
    🟩 nvcc               Pass: 100%/1   | Total: 14m 47s | Avg: 14m 47s | Max: 14m 47s
  🟩 cxx
    🟩 GCC13              Pass: 100%/1   | Total: 14m 47s | Avg: 14m 47s | Max: 14m 47s
  🟩 cxx_family
    🟩 GCC                Pass: 100%/1   | Total: 14m 47s | Avg: 14m 47s | Max: 14m 47s
  🟩 gpu
    🟩 v100               Pass: 100%/1   | Total: 14m 47s | Avg: 14m 47s | Max: 14m 47s
  🟩 jobs
    🟩 Test               Pass: 100%/1   | Total: 14m 47s | Avg: 14m 47s | Max: 14m 47s
  

👃 Inspect Changes

Modifications in project?

	Project
	CCCL Infrastructure
	libcu++
+/-	CUB
	Thrust
	CUDA Experimental
	pycuda
	CUDA C Core Library

Modifications in project or dependencies?

	Project
	CCCL Infrastructure
	libcu++
+/-	CUB
+/-	Thrust
	CUDA Experimental
+/-	pycuda
+/-	CUDA C Core Library

🏃‍ Runner counts (total jobs: 208)

#	Runner
171	linux-amd64-cpu16
16	linux-arm64-cpu16
12	linux-amd64-gpu-v100-latest-1
9	windows-amd64-cpu16