[x265] GCC 4.8.2 warning in slicetype.cpp (aggr. loop opt.) 64b HBD only

[Steve Borho]

On 02/25, Mario *LigH* Rohkr??mer wrote:
> Only while compiling for x86-64 with HIGH_BIT_DEPTH:
> 
> +----
> h:/MSYS/home/Entwicklung/x265/source/encoder/slicetype.cpp: In
> member function 'void
> x265::LookaheadTLD::lowresIntraEstimate(x265::Lowres&)':
> h:/MSYS/home/Entwicklung/x265/source/encoder/slicetype.cpp:262:135:
> warning: iteration 17u invokes undefined behavior
> [-Waggressive-loop-optimizations]
>                    neighbours[1][i]           = (neighbours[0][i -
> 1]           + (neighbours[0][i] << 1)           + neighbours[0][i +
> 1]      + 2) >> 2;
>                                                                                                                                          ^
> cc1plus.exe: note: containing loop

This looks like a valid warning, reviewing the intra sample code for
lookahead now.

-- 
Steve Borho