On Wed, 14 Oct 2015, Kirill Yukhin wrote: > Is it ok for trunk?
This patch has no documentation. Documentation for new attributes must be added to extend.texi. > Enables creation of one or more versions that can process multiple > arguments using SIMD instructions from a single invocation from a SIMD > loop. It is ultimately an alias to `omp declare simd’ pragma, available > w/o additional compiler switches. It is prohibited to use the attribute > along with Cilk Plus’s `vector’ attribute. If the attribute is specified > and `pragma omp declare simd’ presents on a decl, then the attribute is > ignored. This is missing the key information that it's not just about *creation* of the versions, it's about (in the case of an external declaration) *assuming* such versions were created in another translation unit. And you should have a link to the external ABI documents specifying for each architecture for which this involves such an assumption exactly what versions may be assumed to be present - this is what's required to be able to use the attribute in headers for a library and know that future GCC versions won't reinterpret the attribute as implying some versions for future ISA extensions are also present. I wonder whether the syntax for this attribute should allow optional arguments to describe what versions are present, but maybe that can be deferred until e.g. you want a way in future for a library to specify it has an AVX1024 version of a function as well as the baseline ABI set of versions. -- Joseph S. Myers jos...@codesourcery.com
