From mboxrd@z Thu Jan  1 00:00:00 1970
From: Richard Henderson <rth@redhat.com>
To: Aldy Hernandez <aldyh@redhat.com>
Cc: "Joseph S. Myers" <jsm28@cam.ac.uk>, gcc@gcc.gnu.org
Subject: Re: front end changes for altivec
Date: Tue, 27 Nov 2001 17:02:00 -0000
Message-ID: <20011127170133.A30341@redhat.com>
References: <Pine.LNX.4.33.0111270053270.4999-100000@kern.srcf.societies.cam.ac.uk> <1006874643.5176.8.camel@litecycle.cc.andrews.edu> <20011127132756.A30114@redhat.com> <1006898082.5178.41.camel@litecycle.cc.andrews.edu> <20011127140031.E30114@redhat.com> <1006908775.5178.45.camel@litecycle.cc.andrews.edu>
X-SW-Source: 2001-11/msg01434.html
Message-ID: <20011127170200.5AV9pqFMOsxgpjt-DbOO2TBm7fkDxoNjHoFKDXvAqP4@z>

On Tue, Nov 27, 2001 at 06:52:55PM -0600, Aldy Hernandez wrote:
> > How about __vector_size__(16) then?
> 
> can anyone think of any way to get:
> 
> 	vector int foo;		/* v4si */
> 	vector short bar;	/* v2hi */
> 	vector char hot;	/* v16qi */
> 	etc
> 
> working for altivec in a target independent manner?

Modulo the varying size of "short",

  #define __vector  __attribute__((__vector_size__(16)))

works.  And char/short/int doesn't actually vary *that* widely.
The targets for which these are not 1, 2 and 4 octets wide are
fairly rare, so I'm willing to gloss over that.  Especially
since you can also work around this like so:

	#if SHRT_MAX == 32767
	typedef unsigned short u16;
	#elif INT_MAX == 32767
	typedef unsigned int u16;
	#else
	#error you're strange
	#endif

	__vector u16 foo;

I think for stuff written for gcc itself we should encourage the use
of mode(V4SI), or some other explicit element size + vector width
syntax yet to be determined.


r~