Maybe related to PR19362 and PR20244, but these are not marked as a regression. The following code ICEs with -O3, adding the fordward decl for function avoids the ICE.
Matthias int main() { struct {int i;} x; function(x); return 0; } function (int k){} -- Summary: [4.0 4.1 regression] ICE in fold_convert, at fold- const.c:1922 Product: gcc Version: 4.0.2 Status: UNCONFIRMED Severity: normal Priority: P2 Component: other AssignedTo: unassigned at gcc dot gnu dot org ReportedBy: debian-gcc at lists dot debian dot org http://gcc.gnu.org/bugzilla/show_bug.cgi?id=24210