On Mon, 26 Jun 2023, Jan Hubicka wrote:
> Hi,
> compiling the testcase from PR109849 (which uses std:vector based stack to
> drive a loop) with profile feedbakc leads to profile mismatches introduced by
> tree-ssa-dce. This is the new code to produce unified forwarder blocks for
> PHIs.
>
> I am not including the testcase itself since
> checking it for Invalid sum is probably going to be too fragile and this
> should
> show in our LNT testers. The patch however fixes the mismatch.
>
> Bootstrapped/regtested x86_64-linux and plan to commit it shortly.
Thanks - can you also fix affected branches?
Richard.
> gcc/ChangeLog:
>
> PR tree-optimization/109849
> * tree-ssa-dce.cc (make_forwarders_with_degenerate_phis): Fix profile
> count of newly constructed forwarder block.
>
> diff --git a/gcc/tree-ssa-dce.cc b/gcc/tree-ssa-dce.cc
> index 2949957f883..f0b02456132 100644
> --- a/gcc/tree-ssa-dce.cc
> +++ b/gcc/tree-ssa-dce.cc
> @@ -1865,12 +1865,15 @@ make_forwarders_with_degenerate_phis (function *fn)
> }
> free_dominance_info (fn, CDI_DOMINATORS);
> basic_block forwarder = split_edge (args[start].first);
> + profile_count count = profile_count::zero ();
> for (unsigned j = start + 1; j < i; ++j)
> {
> edge e = args[j].first;
> redirect_edge_and_branch_force (e, forwarder);
> redirect_edge_var_map_clear (e);
> + count += e->count ();
> }
> + forwarder->count = count;
> if (vphi)
> {
> tree def = copy_ssa_name (vphi_args[0]);
>
--
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)
