Live range shrinkage in pre-reload scheduling

[Kyrill Tkachov]

Hi all,

In haifa-sched.c (in rank_for_schedule) I notice that live range shrinkage is 
not performed when SCHED_PRESSURE_MODEL is used and the comment mentions that it 
results in much worse code.

Could anyone elaborate on this? Was it just empirically noticed on x86_64?

Thanks,
Kyrill