objdump riscv: Stop disassembling addi rd, rs, 0 with a relocation as mv rd, rs?

[Maciej W. Rozycki]

On Tue, 7 Feb 2023, Jan Beulich wrote:

> >  However it may be quite hard to implement given how the GNU disassembler 
> > has been structured; most easily probably by setting the `no_aliases' flag 
> > temporarily for any instruction seen with a relocation attached.  This 
> > could have undesired consequences elsewhere though and would most likely 
> > make Jan unhappy who wants to see aliases in disassembly rather than 
> > machine instruction mnemonics with the immediate forms.
> > 
> >  So instead we may need another flag for the opcode table, such as 
> > INSN_NORELOC, which would exclude the given entry for instructions with 
> > any relocation attached; I think this would be the cleanest approach, 
> > though maybe a little bit more involving implementation-wise.
> 
> Could we get away with simply skipping aliases in general when there's a
> relocation for an insn?

 I think it would be unreasonably inconsistent though.  Also I think we do 
want to keep the `*z' branch forms in disassembly.

  Maciej