reduce memory usage of functor compilation by O(10%)

Reduce the memory footprint of compiling functors.
For example the required ram to compile the hlt2_pp_thor functor cache is reduced by ~ O(10-15%).

Improving the memory footprint of the functors more is going to be hard though because it seems to be just a consequence of the super heavy template usage :/

added Functors enhancement labels

changed the description

added RTA label

/ci-test lhcb-datapkg/PRConfig!224 (merged)

added ci-test-triggered label

• [2022-04-06 14:52] Validation started with lhcb-master-mr#4182

changed title from reduce memory usage of functor compilation by O(10%) in opt+g to reduce memory usage of functor compilation by O(10%)

resolved all threads

merged

mentioned in commit 162aa805

mentioned in issue Moore#421 (closed)