[clang] [openmp] [OpenMP 6.0 ]Codegen for Reduction over private variables with reduction clause (PR #134709)

[LLVM Continuous Integration via cfe-commits]

llvm-ci wrote:

LLVM Buildbot has detected a new failure on builder `openmp-s390x-linux` running on `systemz-1` while building `clang,openmp` at step 6 "test-openmp".

Full details are available at: https://lab.llvm.org/buildbot/#/builders/88/builds/12678

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

```
Step 6 (test-openmp) failure: test (failure)
******************** TEST 'libomp :: worksharing/for/omp_for_private_reduction.cpp' FAILED ********************
Exit Code: 1

Command Output (stdout):
--
# RUN: at line 1
/home/uweigand/sandbox/buildbot/openmp-s390x-linux/llvm.build/./bin/clang++ -fopenmp   -I /home/uweigand/sandbox/buildbot/openmp-s390x-linux/llvm.build/runtimes/runtimes-bins/openmp/runtime/src -I /home/uweigand/sandbox/buildbot/openmp-s390x-linux/llvm.src/openmp/runtime/test -L /home/uweigand/sandbox/buildbot/openmp-s390x-linux/llvm.build/runtimes/runtimes-bins/openmp/runtime/src  -fno-omit-frame-pointer -mbackchain -I /home/uweigand/sandbox/buildbot/openmp-s390x-linux/llvm.src/openmp/runtime/test/ompt -std=c++17 /home/uweigand/sandbox/buildbot/openmp-s390x-linux/llvm.src/openmp/runtime/test/worksharing/for/omp_for_private_reduction.cpp -o /home/uweigand/sandbox/buildbot/openmp-s390x-linux/llvm.build/runtimes/runtimes-bins/openmp/runtime/test/worksharing/for/Output/omp_for_private_reduction.cpp.tmp -lm -latomic -fopenmp-version=60  && /home/uweigand/sandbox/buildbot/openmp-s390x-linux/llvm.build/runtimes/runtimes-bins/openmp/runtime/test/worksharing/for/Output/omp_for_private_reduction.cpp.tmp
# executed command: /home/uweigand/sandbox/buildbot/openmp-s390x-linux/llvm.build/./bin/clang++ -fopenmp -I /home/uweigand/sandbox/buildbot/openmp-s390x-linux/llvm.build/runtimes/runtimes-bins/openmp/runtime/src -I /home/uweigand/sandbox/buildbot/openmp-s390x-linux/llvm.src/openmp/runtime/test -L /home/uweigand/sandbox/buildbot/openmp-s390x-linux/llvm.build/runtimes/runtimes-bins/openmp/runtime/src -fno-omit-frame-pointer -mbackchain -I /home/uweigand/sandbox/buildbot/openmp-s390x-linux/llvm.src/openmp/runtime/test/ompt -std=c++17 /home/uweigand/sandbox/buildbot/openmp-s390x-linux/llvm.src/openmp/runtime/test/worksharing/for/omp_for_private_reduction.cpp -o /home/uweigand/sandbox/buildbot/openmp-s390x-linux/llvm.build/runtimes/runtimes-bins/openmp/runtime/test/worksharing/for/Output/omp_for_private_reduction.cpp.tmp -lm -latomic -fopenmp-version=60
# .---command stderr------------
# | /home/uweigand/sandbox/buildbot/openmp-s390x-linux/llvm.src/openmp/runtime/test/worksharing/for/omp_for_private_reduction.cpp:78:42: error: use of undeclared identifier 'I'
# |    78 |   double _Complex expected = 0.0 + 0.0 * I;
# |       |                                          ^
# | /home/uweigand/sandbox/buildbot/openmp-s390x-linux/llvm.src/openmp/runtime/test/worksharing/for/omp_for_private_reduction.cpp:79:40: error: use of undeclared identifier 'I'
# |    79 |   double _Complex result = 0.0 + 0.0 * I;
# |       |                                        ^
# | /home/uweigand/sandbox/buildbot/openmp-s390x-linux/llvm.src/openmp/runtime/test/worksharing/for/omp_for_private_reduction.cpp:84:22: error: use of undeclared identifier 'I'
# |    84 |     arr[i] = i - i * I;
# |       |                      ^
# | /home/uweigand/sandbox/buildbot/openmp-s390x-linux/llvm.src/openmp/runtime/test/worksharing/for/omp_for_private_reduction.cpp:92:19: error: use of undeclared identifier 'creal'
# |    92 |       real_sum += creal(arr[i]);
# |       |                   ^~~~~
# | /home/uweigand/sandbox/buildbot/openmp-s390x-linux/llvm.src/openmp/runtime/test/worksharing/for/omp_for_private_reduction.cpp:93:19: error: use of undeclared identifier 'cimag'
# |    93 |       imag_sum += cimag(arr[i]);
# |       |                   ^~~~~
# | /home/uweigand/sandbox/buildbot/openmp-s390x-linux/llvm.src/openmp/runtime/test/worksharing/for/omp_for_private_reduction.cpp:96:36: error: use of undeclared identifier 'I'
# |    96 |     result = real_sum + imag_sum * I;
# |       |                                    ^
# | /home/uweigand/sandbox/buildbot/openmp-s390x-linux/llvm.src/openmp/runtime/test/worksharing/for/omp_for_private_reduction.cpp:97:9: error: use of undeclared identifier 'cabs'
# |    97 |     if (cabs(result - expected) > 1e-6) {
# |       |         ^~~~
# | 7 errors generated.
# `-----------------------------
# error: command failed with exit status: 1

--

********************


```

</details>

https://github.com/llvm/llvm-project/pull/134709