[PATCH i386 5/8] [AVX-512] Extend vectorizer hooks.

Eric Botcazou ebotcazou@adacore.com
Thu Jan 2 21:56:00 GMT 2014


> x86-64 ABI has clause about aligning static vars to 128bit boundary at a
> given size.  This was introduced to aid compiler to generate aligned
> vector store/load even if the object may bind to other object file.
> This is set to stone and can not be changed for AVX/SSE.

Yes, but that's irrelevant in 32-bit mode.

> For other objects that are fully under local control we can bump up
> alignment more.  I remember this code was originally supposed to bump up
> to 128bits since it was written long before AVX.  I suppose it would make
> sense to do so when AVX is enabled and we anticipate to use it.

So the same unexpected side-effect (decreasing the alignment) probably happened 
when the maximum alignment was bumped from 128 to 256.

-- 
Eric Botcazou



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