Volatile memory is not general operand

["Paulo J. Matos" <pocmatos at gmail dot com>]

Hi,

I just noticed something very surprising. There's a clause in 
general_operand (recog.c):

    if (! volatile_ok && MEM_VOLATILE_P (op))
        return 0;

Oh... so, a MEM_VOLATILE_P is _not_ a general operand? Why? This is also 
not referred to in the documentation of general operand so it kind of 
caught me by surprise.

Before gimplification I have: INT_PRIORITIESD.10391[iD.10456] ={v} 0;

This is converted to a couple of insn that combine tries to combine into:
(set (mem/s/v:QImode ...) (const_int 0))

I have a
(set (match_operand:QImode "nonimmediate_operand" "")
     (match_operand:QImode "general_operand" ""))

However, the insn doesn't match cause nonimmediate_operand returns false 
for (mem/s/v ...).

Why is this? And what can I do to match this set? I guess I can only 
create another pattern. I am just amazed that a volatile memory is not a 
general_operand.

Cheers,

PMatos