On 18 June 2014 05:49, Jeff Law <l...@redhat.com> wrote: > On 06/11/14 04:05, Zhenqiang Chen wrote: >> >> On 10 June 2014 19:06, Steven Bosscher <stevenb....@gmail.com> wrote: >>> >>> On Tue, Jun 10, 2014 at 11:22 AM, Zhenqiang Chen wrote: >>>> >>>> Hi, >>>> >>>> For loop2-invariant pass, when flag_ira_loop_pressure is enabled, >>>> function gain_for_invariant checks the pressures of all register >>>> classes. This does not make sense since one invariant might impact >>>> only one register class. >>>> >>>> The patch enhances functions get_inv_cost and gain_for_invariant to >>>> check only the register pressure of the invariant if possible. >>> >>> >>> This patch may work for targets with more-or-less orthogonal reg >>> classes, but not if there is a lot of overlap between reg classes. >> >> >> Yes. I need check the overlap between reg classes. >> >> Patch is updated to check all overlap reg classes by >> reg_classes_intersect_p: > > Just so I'm sure I know what you're trying to do. > > You want to map the pseudo back to its likely class(es) then look at how > those classes (and only those classes) would be impacted from a register > pressure standpoint if the pseudo was hoisted as an invariant?
Yes. > This is primarily achieved by returning the class of the invariant, then > filtering out any non-intersecting classes in gain_for_invariant, right? Yes. This is what I want to do since I found some invariant which register class is NO_REGS (memory write) or SSE_REGS is blocked by GENERAL_REGS' register pressure. Thanks! -Zhenqiang
