[patch 0/4] RFC: current prefetch patches

[Christian Borntraeger]

This set 4 of four patches is the current state of my work to improve
the prefetch code of gcc.

patch1 does some initial settings for s390x.
patch2 adds some more debugging if prefetches are omitted.
patch3 tries to improve the prefetching for large prefetch_before values
patch4 tries to implement prefetching for loops with non-constant but
  loop invariant step

patch2 should be ok to mainline, all other patches probably need some
more testing and tuning. I just wanted to ask for initial feedback,
especially for patch 4.

Christian