[Bug ada/81361] [8 regression] broken exception handling at -O2

[ebotcazou at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=81361

--- Comment #7 from Eric Botcazou <ebotcazou at gcc dot gnu.org> ---
Created attachment 42177
  --> https://gcc.gnu.org/bugzilla/attachment.cgi?id=42177&action=edit
Tentative fix

Lightly tested on Darwin and Linux so far.