fix(tensilelite): Accept .dat.zlib in --use-cache existence check (#8892)

## Motivation

PR #8294 changed `writeMsgPack()` to compress library catalogs with
zlib, producing `.dat.zlib` files instead of `.dat`. The C++ runtime's
`fileToMsgObject()` was updated to probe for `.zlib` automatically, but
the Python `--use-cache` existence check in `BenchmarkProblems.py` was
missed — it still checks only for `.dat`, causing all `--use-cache`
benchmark tests to FATAL when `LibraryFormat=msgpack`.

## Technical Details

Widen the `os.path.isfile()` existence check to accept both `.dat` and
`.dat.zlib` on disk. The path passed to the C++ client stays as `.dat`,
matching the C++ probe convention from PR #8294 where
`fileToMsgObject()` tries `filename + ".zlib"` before the base file.

## Test Plan

- [x] Emulation CI: common tests pass with `LibraryFormat=msgpack`
- [x] No change to `tensileLibraryFile()` or `writeClientConfigIni` —
C++ client probe convention preserved
- [x] Jenkins `tox -e py3` (yaml format, unaffected path)

## Submission Checklist

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

JIRA ID: AIHPBLAS-3508

Co-authored-by: Claude Opus 4.6 <noreply@anthropic.com>

Author: archana-ramalingam

projects/hipblaslt/tensilelite/Tensile/BenchmarkProblems.py

@@ -758,7 +758,9 @@ def _benchmarkProblemType(problemTypeConfig, problemSizeGroupConfig, problemSize
             outFile = os.path.join(sourcePath, "ClientParameters.ini")
 
             cachedLibraryFile = tensileLibraryFile(sourcePath, gfxName, globalParameters["LibraryFormat"])
-            if not os.path.isfile(cachedLibraryFile):
+            # writeMsgPack produces .dat.zlib; accept both on disk.
+            if not os.path.isfile(cachedLibraryFile) \
+                    and not os.path.isfile(str(cachedLibraryFile) + ".zlib"):
                 printExit(
                     f"cache.yaml refers to a library file that no longer "
                     f"exists on disk: {cachedLibraryFile}. The cache directory may "

projects/hipblaslt/tensilelite/Tensile/Tests/unit/test_benchmarkProblems_cache_library_file.py

@@ -83,6 +83,23 @@ class StubBenchmarkStep:
     )
 
 
+def test_cached_path_accepts_zlib_compressed_library_file():
+    """The existence check must accept .dat.zlib when .dat is absent.
+
+    writeMsgPack produces .dat.zlib (PR #8294). The C++ client probes for
+    .zlib automatically, so cachedLibraryFile stays as .dat — but the
+    Python guard must not FATAL when only .dat.zlib exists on disk.
+    """
+    src = inspect.getsource(bp._benchmarkProblemType)
+    cached_branch = src.split("Using cached solution data", 1)[1]
+    cached_branch = cached_branch.split("writeSolutions", 1)[0]
+    assert '".zlib"' in cached_branch, (
+        "Cached path must check for .dat.zlib fallback alongside .dat. "
+        "writeMsgPack produces .dat.zlib; without this check, --use-cache "
+        "FATALs with 'library file no longer exists' for msgpack format."
+    )
+
+
 def test_cached_path_uses_loaded_LibraryFile_not_recompute():
     """The cached branch of _benchmarkProblemType must use the LibraryFile
     that flowed back from _loadCacheIfMatches, NOT recompute via libraryDir()."""