[PATCH 2/2] arm: lib: xor-neon: disable clang vectorization

Arvind Sankar nivedita at alum.mit.edu
Thu Nov 12 16:50:33 EST 2020


On Wed, Nov 11, 2020 at 04:15:59PM +0200, Adrian Ratiu wrote:
> On Tue, 10 Nov 2020, Nick Desaulniers <ndesaulniers at google.com> 
> wrote:
> > 
> > Yes, though additionally Arvind points out that this code is 
> > kind of curious if there was overlap; maybe the parameters 
> > should just be restrict-qualified. 
> >
> 
> For now I think I'll just re-send the GCC changes and leave the 
> Clang optimization as is, until we better understand what's 
> happening and what's the best way to enable it.
> 

Note that the __restrict__ keywords also help GCC -- it saves it from
having to emit the non-vectorized version and switch between the two at
runtime. If we can verify it's safe, it's a good thing to add all
around.



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