Re: [PATCH 09/12] [i386] Add patterns and predicates foutline-msabi-xlouges

[Daniel Santos <daniel.santos@pobox.com>]

On 05/03/2017 01:10 AM, Uros Bizjak wrote:
> The order of subexpressions of parallel in general does not matter.

Thanks, this makes things much clearer.

>> Also, I'm wondering if there's anything wrong with calling ix86_gen_leave ()
>> and plucking the insns out of the generated parallel insn and moving that
>> into my own parallel rather than generating them in my own function.  I
>> guess all the matters is what is cleanest.
> Hm... I'd rather see subexpressions generated "by hand".

OK.  While we're on the topic, are you OK with my changes to 
ix86_emit_leave to generate the notes or would you prefer those by hand 
as well?

Also, are these predicates what you had in mind?  (I haven't actually 
tested them just yet.)

(define_predicate "save_multiple"
   (match_code "parallel")
{
   const unsigned len = XVECLEN (op, 0);
   unsigned i;

   /* Starting from end of vector, count register saves.  */
   for (i = 0; i < len; ++i)
     {
       rtx src, dest, addr;
       rtx e = XVECEXP (op, 0, len - 1 - i);

       if (GET_CODE (e) != SET)
         break;

       src  = SET_SRC (e);
       dest = SET_DEST (e);

       if (!REG_P (src) || !MEM_P (dest))
         break;

       addr = XEXP (dest, 0);

       /* Good if dest address is in RAX.  */
       if (REG_P (addr) && REGNO (addr) == AX_REG)
         continue;

       /* Good if dest address is offset of RAX.  */
       if (GET_CODE (addr) == PLUS
           && REG_P (XEXP (addr, 0))
           && REGNO (XEXP (addr, 0)) == AX_REG)
         continue;

       break;
     }
   return (i >= 12 && i <= 18);
})


(define_predicate "restore_multiple"
   (match_code "parallel")
{
   const unsigned len = XVECLEN (op, 0);
   unsigned i;

   /* Starting from end of vector, count register restores.  */
   for (i = 0; i < len; ++i)
     {
       rtx src, dest, addr;
       rtx e = XVECEXP (op, 0, len - 1 - i);

       if (GET_CODE (e) != SET)
         break;

       src  = SET_SRC (e);
       dest = SET_DEST (e);

       if (!MEM_P (src) || !REG_P (dest))
         break;

       addr = XEXP (src, 0);

       /* Good if src address is in RSI.  */
       if (REG_P (addr) && REGNO (addr) == SI_REG)
         continue;

       /* Good if src address is offset of RSI.  */
       if (GET_CODE (addr) == PLUS
           && REG_P (XEXP (addr, 0))
           && REGNO (XEXP (addr, 0)) == SI_REG)
         continue;

       break;
     }
   return (i >= 12 && i <= 18);
})


Thanks,
Daniel