Re: [patch] MIPS: add mips32r2 patterns to generate ext andins insns.

[David Ung <davidu at mips dot com>]

On Thu, 2005-05-26 at 16:40 +0100, Richard Sandiford wrote:
> Nigel Stephens <nigel@mips.com> writes:
> 
> > David Ung wrote:
> >
> >>+ bool
> >>+ mips_use_ins_ext_p (rtx op, rtx size, rtx position)
> >>+ {
> >>+   HOST_WIDE_INT len, pos;
> >> + +   if (!ISA_HAS_EXT_INS
> >>+       || !register_operand (op, VOIDmode))
> >>+     return false;
> >> + +   len = INTVAL (size);
> >>+   pos = INTVAL (position);
> >> +   +   if (len <= 0 || len >= BITS_PER_WORD || pos < 0
> >>+       || pos + len > BITS_PER_WORD)
> >>+     return false;
> >> +
> >>
> >
> > Looking at this go past, I wonder should that test be using
> > GET_MODE_BITSIZE (GET_MODE (op)) rather than BITS_PER_WORD?
> 
> Good catch.  Yes it should.  And after that change, there should
> also be a check that GET_MODE_BITSIZE (GET_MODE (op)) <= BITS_PER_WORD.
> 
> As it stands, I suppose this is just future-proofing.  TARGET_64BIT is
> never true for mips32r2 anyway.

FYI, this is what its going to look like.  re-running regressions.

David.

/* Return true if (zero_extract OP SIZE POSITION) can be used as the
   source of an "ext" instruction or the destination of an "ins"
   instruction.  OP must be a register operand and the following
   conditions must hold:

     0 <= POSITION < GET_MODE_BITSIZE (GET_MODE (op))
     0 < SIZE <= GET_MODE_BITSIZE (GET_MODE (op))
     0 < POSITION + SIZE <= GET_MODE_BITSIZE (GET_MODE (op))

   Also reject lengths equal to a word as they are better handled
   by the move patterns.  */

bool
mips_use_ins_ext_p (rtx op, rtx size, rtx position)
{
  HOST_WIDE_INT len, pos;

  if (!ISA_HAS_EXT_INS
      || !register_operand (op, VOIDmode)
      || GET_MODE_BITSIZE (GET_MODE (op)) > BITS_PER_WORD)
    return false;

  len = INTVAL (size);
  pos = INTVAL (position);
  
  if (len <= 0 || len >= GET_MODE_BITSIZE (GET_MODE (op)) 
      || pos < 0 || pos + len > GET_MODE_BITSIZE (GET_MODE (op)))
    return false;

  return true;
}