If the decision is taken to remove -fweb, please give me a heads-up as I have a target-specific pass that shares infrastructure with it. I can factor that out to facilitate the removal; just let me know.
Thanks! -- Bill Bill Schmidt, Ph.D. GCC for LInux on Power Linux on Power Toolchain IBM Linux Technology Center wschm...@linux.vnet.ibm.com > On May 31, 2016, at 8:50 AM, Richard Biener <richard.guent...@gmail.com> > wrote: > > On Tue, May 31, 2016 at 1:42 PM, Jan Hubicka <hubi...@ucw.cz> wrote: >>>> I would say we should handle -frename-registers same way as we do >>>> -fschedule-insns. >>>> I.e. enable/disable it on target basis rather than budnle it to loop >>>> unrolling. >>>> But that is for future patch. I will commit this and propose patch making >>>> -fpeel-loops >>>> independent of rename-registers next >>> >>> Ok. Does -fweb still do what its documentation says (enable register >>> allocation to >>> work on pseudos directly)? Given its downside and strong GIMPLE >>> optimizations maybe >>> it is time to remove it? >> >> I will wait with comitting the renaming patch and we will see the effect with >> -fno-unroll-loops on ia64 tester (it probably pays back more on in-order >> target) and we can test effect with -funroll-loops by patching it tomorrow. >> >> I guess IRA does live range pslitting by itself. Register allocator is not >> the >> only pass which does not like reuse of pseudo. Web originally also made >> -fschedule-insns (not -fschedule-insns2) and CSE to work harder. >> >> In tree-SSA world most of reuse is avoided by out-of-ssa pass. Random reuse >> these days is limited to loop unrolling and RTL expansion I think. Without >> unroling webizer renames 204 pseudos on tramp3d that seems close to 0. I can >> try to dig into that. With -funroll-all-loops it renames 17309 registers. >> Of course it would be possible to write unroller specific renamer, but it >> would >> hardly be any wasier than webizer. > > And we have things like -fsplit-ivs-in-unroller that does part of it... > > Richard. > >> Honza >