[Bug target/74563] [6/7 regression] Classic MIPS16 (non-MIPS16e) function return broken

[law at redhat dot com]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=74563

--- Comment #4 from Jeffrey A. Law <law at redhat dot com> ---
I haven't looked at this the dumps for this failure, but I've just narrowed
down a very similar looking issue.

I've got a case where hard register propagation replaces the use of $2 with $sp
in a load in mips16 mode.  And (thankfully) the assembler flags it as an error.

Not sure if the propagator is failing to verify validity or if the MIPS backend
is returning that it's a valid change incorrectly, but I wouldn't at all be
surprised if the BZ is another instance of the same problem.