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Date: Wed, 06 Nov 2002 14:55:00 -0000
From: Richard Henderson <rth@redhat.com>
To: Jan Hubicka <jh@suse.cz>
Cc: gcc-patches@gcc.gnu.org, aj@suse.de
Subject: Re: Simplify floating point conversions III
Message-ID: <20021106225454.GL22215@redhat.com>
Mail-Followup-To: Richard Henderson <rth@redhat.com>,
	Jan Hubicka <jh@suse.cz>, gcc-patches@gcc.gnu.org, aj@suse.de
References: <20021105171400.GX14655@kam.mff.cuni.cz> <20021105173800.GD20534@redhat.com> <20021106092310.GE22059@kam.mff.cuni.cz> <20021106175441.GZ22059@kam.mff.cuni.cz> <20021106180930.GA22066@redhat.com> <20021106214803.GD22059@kam.mff.cuni.cz>
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On Wed, Nov 06, 2002 at 10:48:03PM +0100, Jan Hubicka wrote:
> +       /* Wind away possible cast.  */
> +       if (TREE_CODE (arg0) == NOP_EXPR
> + 	  && (TYPE_PRECISION (TREE_TYPE (arg0))
> + 	      > TYPE_PRECISION (TREE_TYPE (TREE_OPERAND (arg0, 0)))))
> + 	arg0 = TREE_OPERAND (arg0, 0);
[...]
> +       /* Be curefull about integer to fp conversions.
> + 	 These may overflow still.  */
> +       if (FLOAT_TYPE_P (TREE_TYPE (arg0))

I'd rather something like

static tree
strip_float_extensions (exp)
     tree exp;
{
  tree sub, expt, subt;

  if (TREE_CODE (exp) != NOP_EXPR)
    return exp;

  sub = TREE_OPERAND (exp, 0);
  subt = TREE_TYPE (sub);
  expt = TREE_TYPE (exp);

  if (!FLOAT_TYPE_P (subt))
    return exp;

  if (TYPE_PRECISION (subt) > TYPE_PRECISION (expt))
    return exp;

  return strip_float_extensions (sub);
}

> + 	case RDIV_EXPR:
> + 	   {
> + 	     tree arg0 = TREE_OPERAND (expr, 0);
> + 	     tree arg1 = TREE_OPERAND (expr, 1);
> + 
> + 	     /* Unwind possible casts.  */

Useful here as well.


r~