[Bug target/58623] lack of ldp/stp optimization

[amker at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=58623

--- Comment #7 from amker at gcc dot gnu.org ---
Hi Evandro,
There is specific PR for this issue.  But as we know, fwprop often corrupts
optimizations on address expression, for below example:

   add rb, r1, r2
   ldr rx, [rb]
   add rb, rb, #4

It's transformed into below by fwprop:

   add rb, r1, r2
   ldr rx, [r1, r2]
   add rb, rb, #4

This corrupts post-increment opportunity.  Though in different form, it's
actually same issue as in ldp/stp.

I think https://gcc.gnu.org/bugzilla/show_bug.cgi?id=44883 describes the
problem in some manner, and there might be other PR about it too.