[C++-sig] Exposing 128-bytes aligned datatype

Niall Douglas s_sourceforge at nedprod.com
Wed Feb 22 00:49:24 CET 2012

On 21 Feb 2012 at 16:46, VáclavSmilauer wrote:

> > 128 *byte* alignment? Wow. No, no compiler will support that legally 
> > as it would crap all over your stack frame. I vaguely remember that 
> > GCC caps alignment to 40 bytes due to some supported architecture's 
> > stack frame being incapable of going higher.
> > If you're aligning to 128 bytes then you almost certainly need to 
> > revisit how your code is designed and what algorithms are being used. 
> I did not design the OpenCL standard (see
> http://www.khronos.org/registry/cl/api/1.2/cl_platform.h at the end, there is
> cl_double16). Just to assure you, those types are never ever passed on stack.
> That header works just fine with gcc.

I agree that GCC/MSVC needs two alignment specifiers, one for static 
data alignment and another for everything else.

This would be a good candidate for inclusion into the C programming 
language actually. I may propose it to WG14.


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