The method is extracting the minimum number of [1] non-zero free
registers/entries across all register classes. This means that if we
have saturated all register storage for a particular class, renaming
will stop as a whole.
I believe it does make sense to keep renaming and only block renaming in
case an instruction requiring the particular register type is
encountered. This would happen with the Rename::renameInsts method
[1]: https://github.com/gem5/gem5/blob/stable/src/cpu/o3/rename_map.hh#L269
[2]: https://github.com/gem5/gem5/blob/stable/src/cpu/o3/rename.cc#L662
Change-Id: I932826a77a5c0b2e05d8fdcab0e6ca13cf0e3d23
Signed-off-by: Giacomo Travaglini <giacomo.travaglini@arm.com>