Fixed or forbidden register was spilled

[Hans-Peter Nilsson]

> Date: Thu, 26 Nov 1998 17:49:29 -0700
> From: Jeffrey A Law <law@hurl.cygnus.com>

>   In message < 199811262241.XAA08179@ignucius.axis.se >you write:
>   > 
>   > > From: Bill Currie <bcurrie@tssc.co.nz>
>   > > Date: Thu Nov 26 22:18:45 CET 1998
>   > 
>   > [Removed example of correct FD_ZERO asm using '&' constraint
>   > modifier on output]
>   > 
>   > > I'm curious: what about the `+' modifier?  Is it more, or less,
>   > > appropriate than `=&', or is it only a matter of asthetics? 
>   > 
>   > It was not valid for gcc-2.7.2, which might be an issue for
>   > packages like glibc.
> "+" is not valid in an asm for any version of egcs or gcc.  The manuals
> explicitly say not to use it for asms.

Sorry to disagree, but please look again.

 It used to say that it was invalid to use in asms in gcc-2.7.2,
but the manual now (egcs and gcc-2.8.1) instead explicitly lists
is as valid.  So it's a back-compatibility issue and should be
avoided when possible.  The manual could of course be wrong;
I did not check with the code.  8-)

brgds, H-P