[Bug target/94420] [8/9/10 Regression] ICE error: insn does not satisfy its constraints

[segher at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=94420

--- Comment #2 from Segher Boessenkool <segher at gcc dot gnu.org> ---
Reserving a register that already *is* reserved (by the ABI) is undefined,
of course.

But we shouldn't ICE.