unaligned memory access for vectorization

Ajit Kumar Agarwal ajit.kumar.agarwal@xilinx.com
Thu Feb 12 14:01:00 GMT 2015


Hello All:

The unaligned array access are the blocking factor in the vectorization. This is due to unaligned load and stores with respect to
SIMD instructions are costly operations. 

To enable the vectorizations for unaligned array access the loop peeling is done to make the multiversioning of the loop with 
a loop for the iterations for unaligned array access where the code is non vectorized and also the loop where the loop can be 
vectorized for aligned access. This is possible with loop multiversioning to not to generate the unaligned moves.


Can I know the scope of the above optimization and pointer to the code in GCC where this optimizations is implemented.
If not implemented , it's good to have this optimization.

Thoughts Please?

Thanks & Regards
Ajit 




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