equivalent of __declspec(align(32)) double aligned_array[size] ?

[Azua_Garcia__Giovann]

Hello,

What's the equivalent using the Intel compiler of the MSVC __declspec(align(32)) double aligned_array[size] ?

Or just using the -align compiler option and declaring as shown below is enough to ensure AVX alignment?

double aligned_array[size];

btw I would like to find the official Intel Compiler release 13 beta user guide and extensive documentation in PDF is there any?

TIA,
Best regards,
Giovanni

[Georg_Z_Intel · Accepted solution]

Hello Giovanni,

it's the same (both for Windows* & Linux*/Mac OS* X). The following links to our documentation might be useful for you:

Function Annotations and the SIMD Directive for Vectorization:
http://redfort-software.intel.com/sites/products/documentation/hpc/composerxe/en-us/2011Update/cpp/lin/optaps/common/optaps_vec_support.htm

Alignment Support:
http://redfort-software.intel.com/sites/products/documentation/hpc/composerxe/en-us/2011Update/cpp/lin/intref_cls/common/intref_alignment_support.htm

Details of Intel® Advanced Vector Extensions Intrinsics:
http://redfort-software.intel.com/sites/products/documentation/hpc/composerxe/en-us/2011Update/cpp/lin/intref_cls/common/intref_avx_details.htm

BETA phase is already over and there's no access to it anymore. However, in one month there will be the new version out.

Best regards,

Georg Zitzlsberger

[TimP]

declspec usage is the same in ICL as in MSVC.  Setting AVX option by itself doesn't increase data alignments.
I see nothing in the docs to indicate that -Qsfalign may have been extended beyond 16-byte alignment, so you will need the declspec or equivalent if you want 32-byte alignment.  You would only require 32-byte alignment if you specify syntax which requires it, such as #pragma vector aligned,  __assume_aligned__, or aligned move intrinsics.  Other AVX intrinsics support unaligned data (but 32-byte alignment may show performance advantage).
You have a contradiction in terms between "official" release and beta.  If you have the beta compiler, you have what documentation there was.  It looks somewhat preliminary to me.  Don't expect a .pdf.
As Georg implied, the 2011 documentation should still be useful (and more "official") until we have a 2013 release.