[Bug target/90256] Optimizer with interrupt routines

[nulano at nulano dot eu]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=90256

--- Comment #1 from nulano at nulano dot eu ---
Created attachment 46249
  --> https://gcc.gnu.org/bugzilla/attachment.cgi?id=46249&action=edit
code to reproduce