-qunroll

In IBM® XL C/C++ for AIX® 16.1.0 or earlier releases, automatic unrolling is enabled by the -qunroll=auto option at -O2 or higher.

In IBM Open XL C/C++ for AIX 17.1.2, automatic unrolling is enabled by default at -O2 or higher. You can also enable automatic unrolling at -O1 by specifying the -funroll-loops option. In addition, -fno-unroll-loops can be used to disable unrolling of all loops to achieve the same effect as-qnounroll.

In IBM Open XL C/C++ for AIX 17.1.2, there is not an option that is functionally equivalent to -qunroll=n; however, you can use #pragma unroll(n) or #pragma clang loop unroll_count(n) to control unrolling at the source level.