[Bug target/83905] ix86_expand_epilogue modifies the copy of cfun->machine->frame

[rguenth at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=83905

--- Comment #1 from Richard Biener <rguenth at gcc dot gnu.org> ---
To catch such issues when changing by-value to reference _always_ use a const
reference.