http://gcc.gnu.org/bugzilla/show_bug.cgi?id=44382
--- Comment #9 from William J. Schmidt <wschmidt at gcc dot gnu.org> 2011-10-13 17:30:14 UTC --- Just adding some status information well after the fact... We experimented with adding powerpc64 hooks to use the parallel reassociation support from comment #8. We elected not to enable this support because the results for SPEC were negative (quite negative in some cases), due to increased register pressure in loops where spill was already an issue. Our plans at this point are to live with the left-linear association, at least until the spill costs can be mitigated in some fashion. If parallel reassociation had some heuristics that predicted for register pressure (difficult in tree-ssa, I know), it might become practical for us.
