Abdul Wahid Memon <engrwahidmemon@xxxxxxxxx> writes: > Thanks for the response but I still didnt got the answer regarding > whether it is possible to do loop unrolling without using -O1, -O2 or > -O3. What exactly are those flags (along with funroll-all-loops) which > makes loops unroll? The -O options enable some compiler infrastructure, such as the conversion to SSA form, that are required by the loop optimization passes. If the -O options are not used, the infrastructure is not built, and the loop optimization passes, which depend on that infrastructure, can not be run. Ian