[clang] [OpenMP] Fix crash when diagnosing dist_schedule (PR #139277)

[LLVM Continuous Integration via cfe-commits]

llvm-ci wrote:

LLVM Buildbot has detected a new failure on builder `fuchsia-x86_64-linux` running on `fuchsia-debian-64-us-central1-a-1` while building `clang` at step 4 "annotate".

Full details are available at: https://lab.llvm.org/buildbot/#/builders/11/builds/14789

<details>
<summary>Here is the relevant piece of the build log for the reference</summary>

```
Step 4 (annotate) failure: 'python ../llvm-zorg/zorg/buildbot/builders/annotated/fuchsia-linux.py ...' (failure)
...
[849/1366] Running the Clang regression tests
llvm-lit: /var/lib/buildbot/fuchsia-x86_64-linux/llvm-project/llvm/utils/lit/lit/llvm/config.py:520: note: using clang: /var/lib/buildbot/fuchsia-x86_64-linux/build/llvm-build-n_mai_jm/bin/clang
llvm-lit: /var/lib/buildbot/fuchsia-x86_64-linux/llvm-project/llvm/utils/lit/lit/llvm/subst.py:126: note: Did not find cir-opt in /var/lib/buildbot/fuchsia-x86_64-linux/build/llvm-build-n_mai_jm/bin:/var/lib/buildbot/fuchsia-x86_64-linux/build/llvm-build-n_mai_jm/bin
llvm-lit: /var/lib/buildbot/fuchsia-x86_64-linux/llvm-project/llvm/utils/lit/lit/llvm/subst.py:126: note: Did not find clang-repl in /var/lib/buildbot/fuchsia-x86_64-linux/build/llvm-build-n_mai_jm/bin:/var/lib/buildbot/fuchsia-x86_64-linux/build/llvm-build-n_mai_jm/bin
llvm-lit: /var/lib/buildbot/fuchsia-x86_64-linux/llvm-project/llvm/utils/lit/lit/llvm/config.py:520: note: using ld.lld: /var/lib/buildbot/fuchsia-x86_64-linux/build/llvm-build-n_mai_jm/bin/ld.lld
llvm-lit: /var/lib/buildbot/fuchsia-x86_64-linux/llvm-project/llvm/utils/lit/lit/llvm/config.py:520: note: using lld-link: /var/lib/buildbot/fuchsia-x86_64-linux/build/llvm-build-n_mai_jm/bin/lld-link
llvm-lit: /var/lib/buildbot/fuchsia-x86_64-linux/llvm-project/llvm/utils/lit/lit/llvm/config.py:520: note: using ld64.lld: /var/lib/buildbot/fuchsia-x86_64-linux/build/llvm-build-n_mai_jm/bin/ld64.lld
llvm-lit: /var/lib/buildbot/fuchsia-x86_64-linux/llvm-project/llvm/utils/lit/lit/llvm/config.py:520: note: using wasm-ld: /var/lib/buildbot/fuchsia-x86_64-linux/build/llvm-build-n_mai_jm/bin/wasm-ld
-- Testing: 21417 tests, 60 workers --
Testing:  0.. 10.. 20.. 30.. 40.. 50.. 60.. 70
FAIL: Clang :: OpenMP/teams_distribute_dist_schedule_messages.cpp (15500 of 21417)
******************** TEST 'Clang :: OpenMP/teams_distribute_dist_schedule_messages.cpp' FAILED ********************
Exit Code: 1

Command Output (stderr):
--
/var/lib/buildbot/fuchsia-x86_64-linux/build/llvm-build-n_mai_jm/bin/clang -cc1 -internal-isystem /var/lib/buildbot/fuchsia-x86_64-linux/build/llvm-build-n_mai_jm/lib/clang/21/include -nostdsysteminc -verify -fopenmp /var/lib/buildbot/fuchsia-x86_64-linux/llvm-project/clang/test/OpenMP/teams_distribute_dist_schedule_messages.cpp -Wuninitialized # RUN: at line 1
+ /var/lib/buildbot/fuchsia-x86_64-linux/build/llvm-build-n_mai_jm/bin/clang -cc1 -internal-isystem /var/lib/buildbot/fuchsia-x86_64-linux/build/llvm-build-n_mai_jm/lib/clang/21/include -nostdsysteminc -verify -fopenmp /var/lib/buildbot/fuchsia-x86_64-linux/llvm-project/clang/test/OpenMP/teams_distribute_dist_schedule_messages.cpp -Wuninitialized
error: 'expected-error' diagnostics seen but not expected: 
  File /var/lib/buildbot/fuchsia-x86_64-linux/llvm-project/clang/test/OpenMP/teams_distribute_dist_schedule_messages.cpp Line 111: cannot find start ('{{') of expected string
  File /var/lib/buildbot/fuchsia-x86_64-linux/llvm-project/clang/test/OpenMP/teams_distribute_dist_schedule_messages.cpp Line 111: argument to 'dist_schedule' clause must be a strictly positive integer value
2 errors generated.

--

********************
Testing:  0.. 10.. 20.. 30.. 40.. 50.. 60.. 70.. 80.. 90.. 
********************
Failed Tests (1):
  Clang :: OpenMP/teams_distribute_dist_schedule_messages.cpp


Testing Time: 134.87s

Total Discovered Tests: 46922
  Skipped          :     8 (0.02%)
  Unsupported      :   932 (1.99%)
  Passed           : 45954 (97.94%)
  Expectedly Failed:    27 (0.06%)
  Failed           :     1 (0.00%)
[1364/1366] Linking CXX executable unittests/Transforms/Scalar/ScalarTests
FAILED: tools/clang/test/CMakeFiles/check-clang /var/lib/buildbot/fuchsia-x86_64-linux/build/llvm-build-n_mai_jm/tools/clang/test/CMakeFiles/check-clang 
cd /var/lib/buildbot/fuchsia-x86_64-linux/build/llvm-build-n_mai_jm/tools/clang/test && /usr/bin/python3.10 /var/lib/buildbot/fuchsia-x86_64-linux/build/llvm-build-n_mai_jm/./bin/llvm-lit -sv --param USE_Z3_SOLVER=0 /var/lib/buildbot/fuchsia-x86_64-linux/build/llvm-build-n_mai_jm/tools/clang/test
ninja: build stopped: subcommand failed.
['ninja', '-C', '/var/lib/buildbot/fuchsia-x86_64-linux/build/llvm-build-n_mai_jm', 'check-llvm', 'check-clang', 'check-lld'] exited with return code 1.
@@@STEP_FAILURE@@@
Step 7 (check) failure: check (failure)
...
[849/1366] Running the Clang regression tests
llvm-lit: /var/lib/buildbot/fuchsia-x86_64-linux/llvm-project/llvm/utils/lit/lit/llvm/config.py:520: note: using clang: /var/lib/buildbot/fuchsia-x86_64-linux/build/llvm-build-n_mai_jm/bin/clang
llvm-lit: /var/lib/buildbot/fuchsia-x86_64-linux/llvm-project/llvm/utils/lit/lit/llvm/subst.py:126: note: Did not find cir-opt in /var/lib/buildbot/fuchsia-x86_64-linux/build/llvm-build-n_mai_jm/bin:/var/lib/buildbot/fuchsia-x86_64-linux/build/llvm-build-n_mai_jm/bin
llvm-lit: /var/lib/buildbot/fuchsia-x86_64-linux/llvm-project/llvm/utils/lit/lit/llvm/subst.py:126: note: Did not find clang-repl in /var/lib/buildbot/fuchsia-x86_64-linux/build/llvm-build-n_mai_jm/bin:/var/lib/buildbot/fuchsia-x86_64-linux/build/llvm-build-n_mai_jm/bin
llvm-lit: /var/lib/buildbot/fuchsia-x86_64-linux/llvm-project/llvm/utils/lit/lit/llvm/config.py:520: note: using ld.lld: /var/lib/buildbot/fuchsia-x86_64-linux/build/llvm-build-n_mai_jm/bin/ld.lld
llvm-lit: /var/lib/buildbot/fuchsia-x86_64-linux/llvm-project/llvm/utils/lit/lit/llvm/config.py:520: note: using lld-link: /var/lib/buildbot/fuchsia-x86_64-linux/build/llvm-build-n_mai_jm/bin/lld-link
llvm-lit: /var/lib/buildbot/fuchsia-x86_64-linux/llvm-project/llvm/utils/lit/lit/llvm/config.py:520: note: using ld64.lld: /var/lib/buildbot/fuchsia-x86_64-linux/build/llvm-build-n_mai_jm/bin/ld64.lld
llvm-lit: /var/lib/buildbot/fuchsia-x86_64-linux/llvm-project/llvm/utils/lit/lit/llvm/config.py:520: note: using wasm-ld: /var/lib/buildbot/fuchsia-x86_64-linux/build/llvm-build-n_mai_jm/bin/wasm-ld
-- Testing: 21417 tests, 60 workers --
Testing:  0.. 10.. 20.. 30.. 40.. 50.. 60.. 70
FAIL: Clang :: OpenMP/teams_distribute_dist_schedule_messages.cpp (15500 of 21417)
******************** TEST 'Clang :: OpenMP/teams_distribute_dist_schedule_messages.cpp' FAILED ********************
Exit Code: 1

Command Output (stderr):
--
/var/lib/buildbot/fuchsia-x86_64-linux/build/llvm-build-n_mai_jm/bin/clang -cc1 -internal-isystem /var/lib/buildbot/fuchsia-x86_64-linux/build/llvm-build-n_mai_jm/lib/clang/21/include -nostdsysteminc -verify -fopenmp /var/lib/buildbot/fuchsia-x86_64-linux/llvm-project/clang/test/OpenMP/teams_distribute_dist_schedule_messages.cpp -Wuninitialized # RUN: at line 1
+ /var/lib/buildbot/fuchsia-x86_64-linux/build/llvm-build-n_mai_jm/bin/clang -cc1 -internal-isystem /var/lib/buildbot/fuchsia-x86_64-linux/build/llvm-build-n_mai_jm/lib/clang/21/include -nostdsysteminc -verify -fopenmp /var/lib/buildbot/fuchsia-x86_64-linux/llvm-project/clang/test/OpenMP/teams_distribute_dist_schedule_messages.cpp -Wuninitialized
error: 'expected-error' diagnostics seen but not expected: 
  File /var/lib/buildbot/fuchsia-x86_64-linux/llvm-project/clang/test/OpenMP/teams_distribute_dist_schedule_messages.cpp Line 111: cannot find start ('{{') of expected string
  File /var/lib/buildbot/fuchsia-x86_64-linux/llvm-project/clang/test/OpenMP/teams_distribute_dist_schedule_messages.cpp Line 111: argument to 'dist_schedule' clause must be a strictly positive integer value
2 errors generated.

--

********************
Testing:  0.. 10.. 20.. 30.. 40.. 50.. 60.. 70.. 80.. 90.. 
********************
Failed Tests (1):
  Clang :: OpenMP/teams_distribute_dist_schedule_messages.cpp


Testing Time: 134.87s

Total Discovered Tests: 46922
  Skipped          :     8 (0.02%)
  Unsupported      :   932 (1.99%)
  Passed           : 45954 (97.94%)
  Expectedly Failed:    27 (0.06%)
  Failed           :     1 (0.00%)
[1364/1366] Linking CXX executable unittests/Transforms/Scalar/ScalarTests
FAILED: tools/clang/test/CMakeFiles/check-clang /var/lib/buildbot/fuchsia-x86_64-linux/build/llvm-build-n_mai_jm/tools/clang/test/CMakeFiles/check-clang 
cd /var/lib/buildbot/fuchsia-x86_64-linux/build/llvm-build-n_mai_jm/tools/clang/test && /usr/bin/python3.10 /var/lib/buildbot/fuchsia-x86_64-linux/build/llvm-build-n_mai_jm/./bin/llvm-lit -sv --param USE_Z3_SOLVER=0 /var/lib/buildbot/fuchsia-x86_64-linux/build/llvm-build-n_mai_jm/tools/clang/test
ninja: build stopped: subcommand failed.
['ninja', '-C', '/var/lib/buildbot/fuchsia-x86_64-linux/build/llvm-build-n_mai_jm', 'check-llvm', 'check-clang', 'check-lld'] exited with return code 1.
program finished with exit code 0
elapsedTime=1136.763526

```

</details>

https://github.com/llvm/llvm-project/pull/139277