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Re: recent troubles with float vectors & bitwise ops


On Thu, 23 Aug 2007, Ian Lance Taylor wrote:

> I think we should revert the patch, and continue permitting the
> bitwise operations on vector float.
> 
> There seem to be solid reasons to permit this, and no very strong ones
> to prohibit it.  We can consider it to be a GNU extension for vectors.
> Vectors are of course themselves an extension already.

We decided long ago that the extension would be based on what's permitted 
by C++ valarray rather than by a particular CPU's vector intrinsics.  So 
unless C++ valarray allows this operation, I think we should leave it 
prohibited and ensure that the compiler can generate appropriate code for 
these bitwise operations in the presence of casts (the particular integer 
element type used should of course not affect the code for these 
operations either.)

-- 
Joseph S. Myers
joseph@codesourcery.com


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