[RISCV] redundant return-only BB not eliminated

[Robert Guthrie]

On Sun, Aug 30, 2026 at 10:43:22PM -0600, Jeff Law wrote:
>I'd be looking at cfgcleanup.cc, cfgrtl.cc and bb_is_just_return for 
>inspiration.

Thank you, I think I am on the right track then: my solution was making use of bb_is_just_return,
though it failed to bootstrap and I haven't figured out why yet.

>Note this change will save code size, but not likely directly improve 
>performance.  It's still worth doing, but just want to make sure 
>expectations are sane.
>
>I would recommend you get an account on gcc.gnu.org/bugzilla so that 
>you can file this as a bug report ensuring it doesn't get lost.
>
>jeff

Yes, I realize this is a very minor code-size improvement at best,
but it has been quite good for digging in to GCC for the first time,
learning how to inspect/manipulate the CFG, RTL, etc.
I've requested a bugzilla account and I will file one once that is thru.

It might be a good "simple hack of the week" candidate: I am only looking at it
a little each night after the kids are down, so someone can probably beat me to it :)

Thanks for your reply
Robert