[Regression Tests][hipCUB] Implementation of regression subtest for emulation

CHANGELOG.md

@@ -5,14 +5,15 @@ Full documentation for hipCUB is available at [https://rocm.docs.amd.com/project
 ## (Unreleased) hipCUB-x.x.x for ROCm 6.4.0
 
 ### Added
+* Added regression tests to `rtest.py`. These tests recreate scenarios that have caused hardware problems in past emulation environments. Use `python rtest.py [--emulation|-e|--test|-t]=regression` to run these tests.
 * Added `ForEach`, `ForEachN`, `ForEachCopy`, `ForEachCopyN` and `Bulk` functions to have parity with CUB.
 * Added the `hipcub::CubVector` type for CUB parity.
-* Added `--emulation` option added for `rtest.py`
+* Added `--emulation` option for `rtest.py`
+  * Unit tests can be run with `[--emulation|-e|--test|-t]=<test_name>`
 
 ### Changed
-* Edited smoke test options, which runs a subset of the unit tests and ensuring that less than 2gb of VRAM will be used
-  * Smoke tests can be ran with `[--emulation|-e|--test|-t]=smoke`
-* `--test|-t` no longer a required flag for `rtest.py`, instead user can use either `--emulation|-e` or `--test|-t` but not both
+* Changed the subset of tests that are run for smoke tests such that the smoke test will complete with faster run-time and to never exceed 2GB of vram usage. Use `python rtest.py [--emulation|-e|--test|-t]=smoke` to run these tests.
+* The `rtest.py` options have changed. `rtest.py` is now run with at least either `--test|-t` or `--emulation|-e`, but not both options.
 
 ## hipCUB-3.3.0 for ROCm 6.3.0