On Thu, 11 Aug 2022, Jakub Jelinek wrote:
> Hi!
>
> Those 2 checks were just me trying to be extra careful, the
> (phires & 1) == phires and variants it is folded to of course make only sense
> for the -1/0/1/2 result spaceship, for -1/0/1 one can just use comparisons of
> phires. We only floating point spaceship if nans aren't honored, so the
> 2 case is ignored, and if it is, with Aldy's changes we can simplify the
> 2 case away from the phi but the (phires & 1) == phires stayed. It is safe
> to treat the phires comparison as phires >= 0 even then.
>
> Bootstrapped/regtested on x86_64-linux and i686-linux, ok for trunk?
OK.
Thanks,
Richard.
> 2022-08-11 Jakub Jelinek <ja...@redhat.com>
>
> PR tree-optimization/106506
> * tree-ssa-phiopt.cc (spaceship_replacement): Don't punt for
> is_cast or orig_use_lhs cases if phi_bb has 3 predecessors.
>
> * g++.dg/opt/pr94589-2.C: New test.
>
> --- gcc/tree-ssa-phiopt.cc.jj 2022-08-10 09:06:53.000000000 +0200
> +++ gcc/tree-ssa-phiopt.cc 2022-08-10 15:33:32.414641593 +0200
> @@ -2448,8 +2448,6 @@ spaceship_replacement (basic_block cond_
> return false;
> if (SSA_NAME_OCCURS_IN_ABNORMAL_PHI (orig_use_lhs))
> return false;
> - if (EDGE_COUNT (phi_bb->preds) != 4)
> - return false;
> if (!single_imm_use (orig_use_lhs, &use_p, &use_stmt))
> return false;
>
> @@ -2467,8 +2465,6 @@ spaceship_replacement (basic_block cond_
> orig_use_lhs = gimple_assign_lhs (use_stmt);
> if (SSA_NAME_OCCURS_IN_ABNORMAL_PHI (orig_use_lhs))
> return false;
> - if (EDGE_COUNT (phi_bb->preds) != 4)
> - return false;
> if (!single_imm_use (orig_use_lhs, &use_p, &use_stmt))
> return false;
> }
> --- gcc/testsuite/g++.dg/opt/pr94589-2.C.jj 2022-08-10 09:06:52.921213966
> +0200
> +++ gcc/testsuite/g++.dg/opt/pr94589-2.C 2022-08-10 15:45:24.599319922
> +0200
> @@ -1,7 +1,7 @@
> // PR tree-optimization/94589
> // { dg-do compile { target c++20 } }
> // { dg-options "-O2 -g0 -ffast-math -fdump-tree-optimized" }
> -// { dg-final { scan-tree-dump-times "\[ij]_\[0-9]+\\(D\\)
> (?:<|<=|==|!=|>|>=) \[ij]_\[0-9]+\\(D\\)" 12 "optimized" { xfail *-*-* } } }
> +// { dg-final { scan-tree-dump-times "\[ij]_\[0-9]+\\(D\\)
> (?:<|<=|==|!=|>|>=) \[ij]_\[0-9]+\\(D\\)" 12 "optimized" } }
> // { dg-final { scan-tree-dump-times "i_\[0-9]+\\(D\\) (?:<|<=|==|!=|>|>=)
> 5\\.0" 12 "optimized" } }
>
> #include <compare>
>
> Jakub
>
>
--
Richard Biener <rguent...@suse.de>
SUSE Software Solutions Germany GmbH, Frankenstrasse 146, 90461 Nuernberg,
Germany; GF: Ivo Totev, Andrew Myers, Andrew McDonald, Boudien Moerman;
HRB 36809 (AG Nuernberg)
