Possible bug in cse.c affecting pre/post-modify mem access

[A. Skrobov]

>>> If we look in sel-sched-ir.c we see that it calls into hash_rtx_cb
>>> (sigh, bad modularity).   I'm not at all familiar with how the hashing
>>> is used within the selective scheduler, so I can't really say what the
>>> selective scheduler *should* be doing here.
>>
>> OK, I see. Now what do you think would be the best course of action?
>> Leave everything as it is? The selective scheduler may or may not want
>> these memory accesses ignored.
>
> I don't think we can assert even for cse, since AIUI these codes can
> still be used for stack pushes and pops.

But then cse would generate incorrect code when these are used?