<table border="1" cellspacing="0" cellpadding="8">
    <tr>
        <th>Issue</th>
        <td>
            <a href=https://github.com/llvm/llvm-project/issues/61476>61476</a>
        </td>
    </tr>

    <tr>
        <th>Summary</th>
        <td>
            [flang] [OpenMP] MG Benchmark in NPB3.4-OMP fails (UNSUCCESSFUL)
        </td>
    </tr>

    <tr>
      <th>Labels</th>
      <td>
            new issue
      </td>
    </tr>

    <tr>
      <th>Assignees</th>
      <td>
      </td>
    </tr>

    <tr>
      <th>Reporter</th>
      <td>
          k-arrows
      </td>
    </tr>
</table>

<pre>
    NAS Parallel Benchmarks:
https://www.nas.nasa.gov/software/npb.html

I used the following shell script.
```console
#!/bin/bash

class=C
num_threads=4

#download
wget https://www.nas.nasa.gov/assets/npb/NPB3.4.2.tar.gz
tar zxf NPB3.4.2.tar.gz

#set clang and flang
cd NPB3.4.2/NPB3.4-OMP/config
cp -p make.def.template make.def
sed -e 's/gcc/clang/g' -e 's/gfortran/flang-new/g' make.def.template > make.def

#compile
cd ../MG
make MG CLASS=${class}

#execute
cd ../bin
export OMP_NUM_THREADS=${num_threads}
./mg.${class}.x

```

Benchmark result:
```console
 NAS Parallel Benchmarks (NPB3.4-OMP) - MG Benchmark

 No input file. Using compiled defaults
 Size:  512x 512x 512  (class C)
 Iterations:                     20
 Number of available threads:     4

 Initialization time:           4.893 seconds

 iter   1
  iter   5
  iter  10
  iter  15
  iter  20

 Benchmark completed
 VERIFICATION FAILED
 L2 Norm is 0.6061219369640E-06
 The correct L2 Norm is 0.5706732285740E-06


 MG Benchmark Completed.
 Class           = C
 Size            =            512x 512x 512
 Iterations      =                       20
 Time in seconds = 24.43
 Total threads   =                        4
 Avail threads =                        4
 Mop/s total     = 6374.28
 Mop/s/thread    =                  1593.57
 Operation type  = floating point
 Verification    =             UNSUCCESSFUL
 Version         =                    3.4.2
 Compile date    = 17 Mar 2023

 Compile options:
    FC           = flang-new
 FLINK        = $(FC)
    F_LIB        = (none)
    F_INC        = (none)
    FFLAGS       = -O3 -fopenmp
    FLINKFLAGS   = $(FFLAGS)
 RAND         = randi8

```

I have not identified the root cause yet.
</pre>
<img width="1px" height="1px" alt="" src="http://email.email.llvm.org/o/eJyMVsty4rwSfhqx6cJlyzdYsCAQz6FOIKkhOduUsNugM7LkkkTI5On_ki_EZjIzvytxIun7-t5tMWP4USIuSHxH4vWEne1J6cWPKdNaXczkoIqfi91yD09MMyFQwB3K_FQx_cOQcEn8NfGXJ2vrZkUzQrPL5eJJZtwv847qjdDMqNJemEZCM1kfvJOtRMts3xs4GyzAnhBKJYS6cHkEc0IhwOSa19br0Inf_uRKGiWw26UhoQGh2YFL92bmNBSeC2YMCderdinP1as9aWSF24yGSELDQl2kUKxoNy5HtPBX55gxaE3rGqHZ7uku9CKPepZp7_jRSrJMw8d7CV8eXrUbtJALJo_AZAGl-6_zobgyrxqmj9snQrNcyZL3sBqmNVTsB3oFlp7FqhbM4nWnRblQTxEITZ3Rxzx3UhpdNDsSmg4PS6WtZi6sjTVTiZce9asaEt7fqLp6lquq5n3C8gI8j9Bs-61dOw5sv8HqYbnfk3BNaETSuzZv6fpGEr5jfrY3klzmmw18r5W28Lh9et29bF-f__P9frn-lDlMfi_Z8aujN1bqvY_U9nU33Lz2AWg0Z2Gv3fB1lcJvmggInQ0TOoepi8UVMFQJOwVc1mcLJRfowYtxjdLFtoACS3YW1nTgPf9AEi4B4oC-X1_gFDZuworQeYfdWNTMciVNw_jioX5vw7k6oAZVAntjXLCDQLg2VMsddRVsJLecCf7RKADLKxwribzZPASDuZKFGVG5RQ0AQbfs1_F4Hfg365tzOsrbZ2ibyAm02LU7_O_--ybbrJbPm8cdZMvNw31XI_BAYad0BdyA7yV-EtBgHibzJPLvp37SgZ5PCLnSGnM7JsSpn6QhpbM4HRJGVg1zDqvesG7wwapJ2OdDwjWsBnmGm7PBM8r-L-n-kvJV2p95hcBln6aGQiMvCvtzZZnoC-GPIvvygKWrnyvlXxC2qnYfE7CNrt7wJEwjj87GGEKzVvBv3QvieejFaUd7rLuIgP1ZY0sphWLWdVituLR9jaDmJc9b7BeyX3b7l9Xqfr_PXh4-KaZD_yna7Xjv8t32NBRurnaUIIUt00B9Go4qp8equm_gvvwBstVAQetTP8ZbTPaw2f13CHBzkM6ywWxwYl4fNndj1EwqiTegzW71V1D2sPy2H4CmjyFMS1WjrOoBzJnVQwdmNVufAr8vd-uRe5rJgs_-Ors3cGJvCFJZ4AVKy0ve3T-0UhZydjYIP9F6k2IRFvNwzia4CJJ07idxHPmT0yLPZ7MiKaIgCNisDCN_dshZGMzytMQyPMwnfOES5YdBGsR-HPleRA95WcYlLbAIMaEk8rFiXHhCvFWe0scJN-aMiySI0mQi2AGFaW5llEq8QHNIKHWXNL1wnOnhfDQk8gU31nxKsdyK5jrX3h_iNZD47rFGuX1yi9Gc4RI-vz1QMi6a79Gohul8ctZiMb4GHbk9nQ9eripCM6e6-zOttfo_5pbQrDHY9WHj0D8BAAD__8lS2iA">