On Fri, May 30, 2025 at 3:53 AM Andrew Pinski <quic_apin...@quicinc.com> wrote:
>
> Only have cleanup cfg happen if scc copy did some proping.
> This should be a small compile time improvement by not doing cleanup
> cfg if scc copy does nothing.
>
> Also removes TODO_update_ssa since it should not be needed.
OK.
Richard.
> gcc/ChangeLog:
>
> * gimple-ssa-sccopy.cc (scc_copy_prop::replace_scc_by_value): Return
> true
> if something was done.
> (scc_copy_prop::propagate): Return true if something was changed.
> (pass_sccopy::execute): Return TODO_cleanup_cfg if a prop happened.
>
> Signed-off-by: Andrew Pinski <quic_apin...@quicinc.com>
> ---
> gcc/gimple-ssa-sccopy.cc | 20 ++++++++++++--------
> 1 file changed, 12 insertions(+), 8 deletions(-)
>
> diff --git a/gcc/gimple-ssa-sccopy.cc b/gcc/gimple-ssa-sccopy.cc
> index ee2a7fa8a72..c93374572a9 100644
> --- a/gcc/gimple-ssa-sccopy.cc
> +++ b/gcc/gimple-ssa-sccopy.cc
> @@ -464,7 +464,7 @@ class scc_copy_prop
> public:
> scc_copy_prop ();
> ~scc_copy_prop ();
> - void propagate ();
> + bool propagate ();
>
> private:
> /* Bitmap tracking statements which were propagated so that they can be
> @@ -474,15 +474,16 @@ private:
> void visit_op (tree op, hash_set<tree> &outer_ops,
> hash_set<gimple *> &scc_set, bool &is_inner,
> tree &last_outer_op);
> - void replace_scc_by_value (vec<gimple *> scc, tree val);
> + bool replace_scc_by_value (vec<gimple *> scc, tree val);
> };
>
> /* For each statement from given SCC, replace its usages by value
> VAL. */
>
> -void
> +bool
> scc_copy_prop::replace_scc_by_value (vec<gimple *> scc, tree val)
> {
> + bool didsomething = false;
> for (gimple *stmt : scc)
> {
> tree name = gimple_get_lhs (stmt);
> @@ -497,10 +498,12 @@ scc_copy_prop::replace_scc_by_value (vec<gimple *> scc,
> tree val)
> }
> replace_uses_by (name, val);
> bitmap_set_bit (dead_stmts, SSA_NAME_VERSION (name));
> + didsomething = true;
> }
>
> if (dump_file)
> fprintf (dump_file, "Replacing SCC of size %d\n", scc.length ());
> + return didsomething;
> }
>
> /* Part of 'scc_copy_prop::propagate ()'. */
> @@ -566,9 +569,10 @@ scc_copy_prop::visit_op (tree op, hash_set<tree>
> &outer_ops,
> Braun, Buchwald, Hack, Leissa, Mallon, Zwinkau, 2013, LNCS vol. 7791,
> Section 3.2. */
>
> -void
> +bool
> scc_copy_prop::propagate ()
> {
> + bool didsomething = false;
> auto_vec<gimple *> useful_stmts = get_all_stmt_may_generate_copy ();
> scc_discovery discovery;
>
> @@ -636,7 +640,7 @@ scc_copy_prop::propagate ()
> {
> /* The only operand in outer_ops. */
> tree outer_op = last_outer_op;
> - replace_scc_by_value (scc, outer_op);
> + didsomething |= replace_scc_by_value (scc, outer_op);
> }
> else if (outer_ops.elements () > 1)
> {
> @@ -651,6 +655,7 @@ scc_copy_prop::propagate ()
>
> scc.release ();
> }
> + return didsomething;
> }
>
> scc_copy_prop::scc_copy_prop ()
> @@ -683,7 +688,7 @@ const pass_data pass_data_sccopy =
> 0, /* properties_provided */
> 0, /* properties_destroyed */
> 0, /* todo_flags_start */
> - TODO_update_ssa | TODO_cleanup_cfg, /* todo_flags_finish */
> + 0, /* todo_flags_finish */
> };
>
> class pass_sccopy : public gimple_opt_pass
> @@ -703,8 +708,7 @@ unsigned
> pass_sccopy::execute (function *)
> {
> scc_copy_prop sccopy;
> - sccopy.propagate ();
> - return 0;
> + return sccopy.propagate () ? TODO_cleanup_cfg : 0;
> }
>
> } // anon namespace
> --
> 2.43.0
>
