Re: [PATCH 0/3] VAX backend preparatory updates for switching to LRA

[Koning, Paul via Gcc-patches]

> On Apr 21, 2021, at 5:32 PM, Maciej W. Rozycki <ma...@orcam.me.uk> wrote:
> 
> ...
> OTOH switching to LRA regresses code generation seriously, by making the 
> indexed and indirect VAX address modes severely underutilised, so while 
> with these changes in place the backend can be switched to LRA with just a 
> trivial to remove the redefinition of TARGET_LRA_P, I think it is not yet 
> the right time to do it.

I noticed similar issues with pdp11, which at the moment allows LRA via a -mlra 
switch but doesn't make it the default.  Another mode that isn't handled well 
(or at all) by LRA is autoincrement/autodecrement.  It would be great if all 
these things could be done better, that would help several targets.  (I wonder 
if m68k would be another; doesn't it have similar addressing modes at least on 
the 68040?)

        paul