Prevent copy propagation from a non-frame related insn to a frame related insn

[Segher Boessenkool]

On Mon, Nov 03, 2025 at 09:45:50AM +0100, Eric Botcazou wrote:
> > I would deeply appreciate if the community can provide feedback as to
> > whether preventing hardreg copy propagation based on the frame-relatedness
> > of the instructions is fine.
> 
> This looks like the most straightforward approach, so I'd give it a try and 
> post a patch along these lines on the gcc-patches@ list (you can CC me on it).
> If other people come up with a better idea, we can further discuss from there.

Thank you!

As a follow-up, we'll post a patch to make the insns generated by
__builtin_get_return_address (and its parent
__builtin_get_frame_address) marked RTX_FRAME_RELATED (which really
means: has its CFI automatically generated).  This will then allow the
insns in the motivating testcase to be CSE'd again (but without causing
problems, this time :-) )


Segher