It seems there’s a problem when the loop index exceeds the int32 limit. I ran a test here: GitHub - gha3mi/nvfortran-dc-bug
fpm @nv-multicore --verbose
Here are the outputs:
n = 1073741824
chunk = 2147483647
huge(int32) = 2147483647
huge(int64) = 9223372036854775807
Initialize : 1.064724000 [s]
Elapsed time: 0.947305000 [s]
Finalize : 1.265888000 [s]
n = 2147483648
chunk = 2147483647
huge(int32) = 2147483647
huge(int64) = 9223372036854775807
Initialize : 2.124329000 [s]
Elapsed time: 2.014653000 [s]
Finalize : 2.347173000 [s]
n = 3221225472
chunk = 2147483647
huge(int32) = 2147483647
huge(int64) = 9223372036854775807
Initialize : 3.274863000 [s]
Elapsed time: 2.804645000 [s]
Finalize : 3.312508000 [s]
n = 4294967296
chunk = 2147483647
huge(int32) = 2147483647
huge(int64) = 9223372036854775807
Initialize : 7.620918000 [s]
Elapsed time: 25.498055000 [s]
Finalize : 6.859171000 [s]