From mboxrd@z Thu Jan  1 00:00:00 1970
From: Richard Earnshaw <rearnsha@arm.com>
To: Richard Henderson <rth@cygnus.com>
Cc: rearnsha@arm.com
Subject: Re: cross from alpha to arm 
Date: Wed, 15 Oct 1997 20:16:00 -0000
Message-id: <199710152144.WAA23392@sun52.NIS.cambridge>
References: <19971015110437.49550@dot.cygnus.com>
X-SW-Source: 1997-10/msg00621.html

> On Wed, Oct 15, 1997 at 09:15:25AM +0800, Stephen Williams wrote:
> > + #if HOST_BITS_PER_WIDE_INT > 32
> > +   if (i & 0xffffffff00000000LL) return FALSE;
> > + #endif
> 
> Make this instead
> 
>   if (i & ~(unsigned HOST_WIDE_INT) 0xffffffff) return FALSE;
> 
> The LL will mess up non-gcc 64-bit hosts, and the conditional
> will be optimized away on hosts it doesn't matter for.
> 
> 
> r~

While this is better, I think you would get better code if you failed 
numbers that weren't the equivalent of a sign-extended 32 bit number.  
Indeed some of the code in output_move_double currently assumes this 
(though this probably needs fixing).

Something like:

{
  unsigned HOST_WIDE_INT mask = ~0xFF;
  HOST_WIDE_INT j = i >> 31;

  if (j != 0 && j != (HOST_WIDE_INT) -1)
    return FALSE;

  /* Fast return for 0 and powers of 2 */
  if ((i & (i - 1)) == 0)