Revital Eres <revital.e...@linaro.org> writes: > Another issue is related to the regression I saw with SMS in libav's > dsputil-ssd_int8_vs_int16_c. > Consulting with Ayal regarding this it seemed that the > regression was due to dependence between accumulations that can be > avoided, more specifically we had the following case in vector code: > > vec1 = vec1 + ... > ... > vec1 = vec1+ ... > ... > vec1 = vec1+ ... > ... > vec1 = vec1+... > > to resolve this, I implemented a hack similar to MVE optimiation in > the loop-unroller as follows: > > vec1 = vec1 + ... > ... > vec2 = vec2+ ... > ... > vec3 = vec3+ ... > ... > vec4 = vec4+...
While I agree that's a useful transformation, do you have a few more details about the SMS regression? I assume both the non-SMS and SMS loops use the: vec1 = vec1 + ... ... vec1 = vec1+ ... ... vec1 = vec1+ ... ... vec1 = vec1+... chain, so what makes the SMS version of it worse than the non-SMS version? Richard _______________________________________________ linaro-toolchain mailing list linaro-toolchain@lists.linaro.org http://lists.linaro.org/mailman/listinfo/linaro-toolchain
