On 6/12/24 13:56, Patrick Palka wrote:
Bootstrapped and regtested on x86_64-pc-linux-gnu, does this look OK for trunk/14?-- >8 -- Here during overload resolution we have two strictly viable ambiguous candidates #1 and #2, and two non-strictly viable candidates #3 and #4 which we hold on to ever since r14-6522. These latter candidates have an empty third arg conversion since the second arg conversion was deemed bad. This ends up causing an ICE during joust for #3 and #4 due to this empty arg conversion. We can fix this by making joust robust to empty arg conversions, but in this situation we shouldn't need to compare #3 and #4 at all given that we have a strictly viable candidate. To that end, this patch makes tourney shortcut considering non-strictly viable candidates upon encountering ambiguity between two strictly viable candidates, taking advantage of the fact that the candidates list is sorted according to viability via splice_viable. PR c++/115239 gcc/cp/ChangeLog: * call.cc (tourney): Don't consider a non-strictly viable candidate as the champ if there was ambiguity between two strictly viable candidates. gcc/testsuite/ChangeLog: * g++.dg/overload/error7.C: New test. --- gcc/cp/call.cc | 4 +++- gcc/testsuite/g++.dg/overload/error7.C | 10 ++++++++++ 2 files changed, 13 insertions(+), 1 deletion(-) create mode 100644 gcc/testsuite/g++.dg/overload/error7.C diff --git a/gcc/cp/call.cc b/gcc/cp/call.cc index ed68eb3c568..82c70f5c39f 100644 --- a/gcc/cp/call.cc +++ b/gcc/cp/call.cc @@ -13484,9 +13484,11 @@ tourney (struct z_candidate *candidates, tsubst_flags_t complain) } else { + z_candidate *prev_champ = *champ; previous_worse_champ = nullptr; champ = &(*challenger)->next; - if (!*champ || !(*champ)->viable) + if (!*champ || !(*champ)->viable + || (prev_champ->viable == 1 && (*champ)->viable == -1))
Maybe (!*champ || (*champ)->viable < prev_champ->viable) ? OK with that change. Jason
