> Hi,
>
> PR 107661 shows that function push_agg_values_for_index_from_edge
> should not attempt to optimize self-recursive call graph edges when
> called from cgraph_edge_brings_all_agg_vals_for_node. Unlike when
> being called from find_aggregate_values_for_callers_subset, we cannot
> expect that any cloning for constants would lead to the edge leading
> from a new clone to the same new clone, in this case it would only be
> redirected to a new callee.
>
> Fixed by adding a parameter to push_agg_values_from_edge whether being
> optimistic about self-recursive edges is possible.
>
> Bootstrapped, LTO-bootstrapped and tested on x86_64-linux. OK for
> trunk?
OK,
thanks!
Honya
>
> Thanks,
>
> Martin
>
>
> gcc/ChangeLog:
>
> 2022-11-22 Martin Jambor <mjam...@suse.cz>
>
> PR ipa/107661
> * ipa-cp.cc (push_agg_values_from_edge): New parameter
> optimize_self_recursion, use it to decide whether to pass interim to
> the helper function.
> (find_aggregate_values_for_callers_subset): Pass true in the new
> parameter of push_agg_values_from_edge.
> (cgraph_edge_brings_all_agg_vals_for_node): Pass false in the new
> parameter of push_agg_values_from_edge.
>
> gcc/testsuite/ChangeLog:
>
> 2022-11-22 Martin Jambor <mjam...@suse.cz>
>
> PR ipa/107661
> * g++.dg/ipa/pr107661.C: New test.
> ---
> gcc/ipa-cp.cc | 18 +++++++-----
> gcc/testsuite/g++.dg/ipa/pr107661.C | 45 +++++++++++++++++++++++++++++
> 2 files changed, 56 insertions(+), 7 deletions(-)
> create mode 100644 gcc/testsuite/g++.dg/ipa/pr107661.C
>
> diff --git a/gcc/ipa-cp.cc b/gcc/ipa-cp.cc
> index d2bcd5e5e69..f0feb4beb8f 100644
> --- a/gcc/ipa-cp.cc
> +++ b/gcc/ipa-cp.cc
> @@ -5752,14 +5752,16 @@ push_agg_values_for_index_from_edge (struct
> cgraph_edge *cs, int index,
> description of ultimate callee of CS or the one it was cloned from (the
> summary where lattices are). If INTERIM is non-NULL, it contains the
> current interim state of collected aggregate values which can be used to
> - compute values passed over self-recursive edges and to skip values which
> - clearly will not be part of intersection with INTERIM. */
> + compute values passed over self-recursive edges (if
> OPTIMIZE_SELF_RECURSION
> + is true) and to skip values which clearly will not be part of intersection
> + with INTERIM. */
>
> static void
> push_agg_values_from_edge (struct cgraph_edge *cs,
> ipa_node_params *dest_info,
> vec<ipa_argagg_value> *res,
> - const ipa_argagg_value_list *interim)
> + const ipa_argagg_value_list *interim,
> + bool optimize_self_recursion)
> {
> ipa_edge_args *args = ipa_edge_args_sum->get (cs);
> if (!args)
> @@ -5785,7 +5787,9 @@ push_agg_values_from_edge (struct cgraph_edge *cs,
> ipcp_param_lattices *plats = ipa_get_parm_lattices (dest_info, index);
> if (plats->aggs_bottom)
> continue;
> - push_agg_values_for_index_from_edge (cs, index, res, interim);
> + push_agg_values_for_index_from_edge (cs, index, res,
> + optimize_self_recursion ? interim
> + : NULL);
> }
> }
>
> @@ -5804,7 +5808,7 @@ find_aggregate_values_for_callers_subset (struct
> cgraph_node *node,
> /* gather_edges_for_value puts a non-recursive call into the first element
> of
> callers if it can. */
> auto_vec<ipa_argagg_value, 32> interim;
> - push_agg_values_from_edge (callers[0], dest_info, &interim, NULL);
> + push_agg_values_from_edge (callers[0], dest_info, &interim, NULL, true);
>
> unsigned valid_entries = interim.length ();
> if (!valid_entries)
> @@ -5815,7 +5819,7 @@ find_aggregate_values_for_callers_subset (struct
> cgraph_node *node,
> {
> auto_vec<ipa_argagg_value, 32> last;
> ipa_argagg_value_list avs (&interim);
> - push_agg_values_from_edge (callers[i], dest_info, &last, &avs);
> + push_agg_values_from_edge (callers[i], dest_info, &last, &avs, true);
>
> valid_entries = intersect_argaggs_with (interim, last);
> if (!valid_entries)
> @@ -5882,7 +5886,7 @@ cgraph_edge_brings_all_agg_vals_for_node (struct
> cgraph_edge *cs,
> ipa_node_params *dest_info = ipa_node_params_sum->get (node);
> gcc_checking_assert (dest_info->ipcp_orig_node);
> dest_info = ipa_node_params_sum->get (dest_info->ipcp_orig_node);
> - push_agg_values_from_edge (cs, dest_info, &edge_values, &existing);
> + push_agg_values_from_edge (cs, dest_info, &edge_values, &existing, false);
> const ipa_argagg_value_list avl (&edge_values);
> return avl.superset_of_p (existing);
> }
> diff --git a/gcc/testsuite/g++.dg/ipa/pr107661.C
> b/gcc/testsuite/g++.dg/ipa/pr107661.C
> new file mode 100644
> index 00000000000..cc6f8538dbf
> --- /dev/null
> +++ b/gcc/testsuite/g++.dg/ipa/pr107661.C
> @@ -0,0 +1,45 @@
> +/* { dg-do run { target c++11 } } */
> +/* { dg-options "-O1 -fipa-cp -fipa-cp-clone" } */
> +
> +struct R {} RGood;
> +struct L {} LBad;
> +
> +volatile int vi;
> +static void __attribute__((noipa)) L_run(void) { vi = 0; __builtin_abort ();
> }
> +static void callback_fn_L(void) { vi = 1; L_run(); }
> +static void callback_fn_R(void) { vi = 2; }
> +
> +struct function_ref {
> + void (*callback)(void) = nullptr;
> +
> + function_ref(L * pl) { callback = callback_fn_L; }
> + function_ref(R * pr) { callback = callback_fn_R; }
> +};
> +
> +// allow one level of recursion to call callback twice
> +static int is_recur(void) {
> + static int n = 0;
> + switch (n++) {
> + case 0: return 1;
> + default: return 0;
> + }
> +}
> +
> +static void do3(volatile int * punused, function_ref Expired) {
> + Expired.callback();
> +
> + if (is_recur())
> + do3(punused, Expired);
> +}
> +
> +static void do1(function_ref Expired) {
> + volatile int unused = 42;
> +
> + do3(&unused, Expired);
> +}
> +
> +int main(int, const char **) { do1(&RGood); return 0; }
> +
> +void seemingly_unused_foo(void) { do1(&LBad); }
> +
> +void (*fnptr)(void) = seemingly_unused_foo;
> --
> 2.38.1
>
