V čet., 15. jul. 2021 10:49 je oseba Kewen.Lin <li...@linux.ibm.com> napisala:
> on 2021/7/15 下午4:23, Uros Bizjak wrote: > > On Thu, Jul 15, 2021 at 10:04 AM Kewen.Lin <li...@linux.ibm.com> wrote: > >> > >> Hi Uros, > >> > >> on 2021/7/15 下午3:17, Uros Bizjak wrote: > >>> On Thu, Jul 15, 2021 at 9:07 AM Kewen.Lin <li...@linux.ibm.com> wrote: > >>>> > >>>> on 2021/7/14 下午3:45, Kewen.Lin via Gcc-patches wrote: > >>>>> on 2021/7/14 下午2:38, Richard Biener wrote: > >>>>>> On Tue, Jul 13, 2021 at 4:59 PM Kewen.Lin <li...@linux.ibm.com> > wrote: > >>>>>>> > >>>>>>> on 2021/7/13 下午8:42, Richard Biener wrote: > >>>>>>>> On Tue, Jul 13, 2021 at 12:25 PM Kewen.Lin <li...@linux.ibm.com> > wrote: > >>>>>> > >>>>>>> I guess the proposed IFN would be directly mapped for > [us]mul_highpart? > >>>>>> > >>>>>> Yes. > >>>>>> > >>>>> > >>>>> Thanks for confirming! The related patch v2 is attached and the > testing > >>>>> is ongoing. > >>>>> > >>>> > >>>> It's bootstrapped & regtested on powerpc64le-linux-gnu P9 and > >>>> aarch64-linux-gnu. But on x86_64-redhat-linux there are XPASSes as > below: > >>>> > >>>> XFAIL->XPASS: gcc.target/i386/pr100637-3w.c scan-assembler pmulhuw > >>>> XFAIL->XPASS: gcc.target/i386/pr100637-3w.c scan-assembler pmulhuw > >>>> XFAIL->XPASS: gcc.target/i386/pr100637-3w.c scan-assembler pmulhw > >>>> XFAIL->XPASS: gcc.target/i386/pr100637-3w.c scan-assembler pmulhw > >>> > >>> These XFAILs should be removed after your patch. > >>> > >> I'm curious whether it's intentional not to specify -fno-vect-cost-model > >> for this test case. As noted above, this case is sensitive on how we > >> cost mult_highpart. Without cost modeling, the XFAILs can be removed > >> only with this mul_highpart pattern support, no matter how we model it > >> (x86 part of this patch exists or not). > >> > >>> This is PR100696 [1], we want PMULH.W here, so x86 part of the patch > >>> is actually not needed. > >>> > >> > >> Thanks for the information! The justification for the x86 part is that: > >> the IFN_MULH essentially covers MULT_HIGHPART_EXPR with mul_highpart > >> optab support, i386 port has already customized costing for > >> MULT_HIGHPART_EXPR (should mean/involve the case with mul_highpart optab > >> support), if we don't follow the same way for IFN_MULH, I'm worried that > >> we may cost the IFN_MULH wrongly. If taking IFN_MULH as normal stmt is > >> a right thing (we shouldn't cost it specially), it at least means we > >> have to adjust ix86_multiplication_cost for MULT_HIGHPART_EXPR when it > >> has direct mul_highpart optab support, I think they should be costed > >> consistently. Does it sound reasonable? > > > > Ah, I was under impression that i386 part was introduced to avoid > > generation of PMULHW instructions in the testcases above (to keep > > XFAILs). Based on your explanation - yes, the costing function should > > be the same. So, the x86 part is OK. > > > > Thanks! It does have the effect to keep XFAILs. ;) I guess the case > doesn't care about the costing much just like most vectorization cases? > If so, do you want me to remove the xfails with one extra option > "-fno-vect-cost-model" along with this patch. > Yes, please do so. The testcase cares only about PMULHW generation. Thanks, Uros. > BR, > Kewen >
