Re: i386 setcc pattern tweek

[Richard Henderson <rth at redhat dot com>]

On Wed, Oct 17, 2001 at 08:11:48PM +0200, Jan Hubicka wrote:
> 	* i386.c (ix86_expand_setcc):  Always expect target to be QImode.

You didn't get all of it.  In particular

  /* Three modes of generation:
     0 -- destination does not overlap compare sources:
          clear dest first, emit strict_low_part setcc.
     1 -- destination does overlap compare sources:
          emit subreg setcc, zero extend.
     2 -- destination is in QImode:
          emit setcc only.

     We don't use mode 0 early in compilation because it confuses CSE.
     There are peepholes to turn mode 1 into mode 0 if things work out
     nicely after reload.  */

  type = cse_not_expected ? 0 : 1;

  if (GET_MODE (dest) == QImode)
    type = 2;
  else if (reg_overlap_mentioned_p (dest, ix86_compare_op0)
           || reg_overlap_mentioned_p (dest, ix86_compare_op1))
    type = 1;

  if (type == 0)
    emit_move_insn (dest, const0_rtx);


but otherwise ok.


r~