Re: [LAD] vectorization

The quest for auto-vectorization continues. Introducing the Intel icc/icpc combo (scroll down ...) On Wed, 2008-04-16 at 17:37 +0200, torbenh(a)gmx.de wrote: If you want to upgrade for speed, consider icc as well. This test is again the "pure CPP" loop only as per above: [root@localhost mixdown]# make icpc -O3 -msse -c mixdown.cpp mixdown.cpp(159): (col. 9) remark: PERMUTED LOOP WAS VECTORIZED. mixdown.cpp(58): (col. 5) remark: LOOP WAS VECTORIZED. mixdown.cpp(54): (col. 5) remark: LOOP WAS VECTORIZED. icpc -O3 -msse -o mixdown *.o [root@localhost mixdown]# ./mixdown Benchmarking mixdown (WITH coeff): : 80 ms <-- shaved off yet another 30% I spend about 20 - 30 minutes on checking pre-conditions, post-conditions and reordering/doubling the ASM in the loop for these two lines of C code, to match the results from g++. I dunno how long time it would (hypothetically) take to match the output from icpc? More interresting would be some "real" code. I just did a preliminary test on a 4-pole filter written in C that I have here. It compiles and something appeared to happen in the vector department, but I am not sure how much or what, yet .. For Altivec: Isn't it so that IBM has some nifty auto-vectorizing compilers as well? --