On Wed, Nov 21, 2018 at 10:48 AM Uros Bizjak <ubiz...@gmail.com> wrote: > > On Wed, Nov 21, 2018 at 12:46 AM Jeff Law <l...@redhat.com> wrote: > > > > On 11/19/18 12:58 PM, Uros Bizjak wrote: > > > Hello! > > > > > > The assert in create_pre_exit at mode-switching.c expects return copy > > > pair with nothing in between. However, the compiler starts mode > > > switching pass with the following sequence: > > > > > > (insn 19 18 16 2 (set (reg:V2SF 21 xmm0) > > > (mem/c:V2SF (plus:DI (reg/f:DI 7 sp) > > > (const_int -72 [0xffffffffffffffb8])) [0 S8 A64])) > > > "pr88070.c":8 1157 {*movv2sf_internal} > > > (nil)) > > > (insn 16 19 20 2 (set (reg:V2SF 0 ax [orig:91 <retval> ] [91]) > > > (reg:V2SF 0 ax [89])) "pr88070.c":8 1157 {*movv2sf_internal} > > > (nil)) > > > (insn 20 16 21 2 (unspec_volatile [ > > > (const_int 0 [0]) > > > ] UNSPECV_BLOCKAGE) "pr88070.c":8 710 {blockage} > > > (nil)) > > > (insn 21 20 23 2 (use (reg:V2SF 21 xmm0)) "pr88070.c":8 -1 > > > (nil)) > > So I know there's an updated patch. But I thought it might be worth > > mentioning that insn 16 here appears to be a nop-move. Removing it > > might address this instance of the problem, but I doubt it's general > > enough to address any larger issues. > > > > You still might want to investigate why it's still in the IL. > > Oh yes, I remember this. > > These nop-moves were removed in Vlad's patch [1],[2]: > > 2013-10-25 Vladimir Makarov <vmaka...@redhat.com> > > ... > * lra-spills.c (lra_final_code_change): Remove useless move insns. > > Which regressed vzeroupper insertion pass [3] that was reported in [4]. > > The functionality was later reverted in [5]: > > 2013-10-26 Vladimir Makarov <vmaka...@redhat.com> > > Revert: > 2013-10-25 Vladimir Makarov <vmaka...@redhat.com> > * lra-spills.c (lra_final_code_change): Remove useless move insns. > > Which IMO can be reintroduced back, now that vzeroupper pass works in > a different way. We actually have a couple of tests in place for > PR58679 [6].
The revert of the revert works OK for PR58679 tests with the latest compiler. Uros.