https://gcc.gnu.org/bugzilla/show_bug.cgi?id=106153
--- Comment #6 from Andy Ross <andy at plausible dot org> --- No, I just had a thinko (hur dur stack grows down, sigh) and jumped too quickly once I thought I had it. All the circumstantial evidence is pointing at a compiler bug here, but this smoking gun isn't. I'll keep looking. Feel free to close this if you need to, I can always reopen if I find something.