Hello,

This reduces peak memory usage for the small test case of PR54146 by
2GB. 24hrs ago peak memory was 9.4 GB in top, but with Richi's patches
from yesterday and with this one, peak memory is now "only" 5.2GB.
About 40% of that is in IRA and reload so there is still room for
improvement, but cutting peak mem almost in half in one day is not a
bad result :-)

Bootstrapped&tested on x86_64-unknown-linux-gnu. OK for trunk?

Ciao!
Steven