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...isely as we can (acknowledging that this is not very precise; it will always be a judgement call). I think it would help these discussions stay on track. -------------- next part -------------- An HTML attachment was scrubbed... URL: <http://lists.llvm.org/pipermail/llvm-dev/attachments/20130606/a5c6538e/attachment.html>

Hi, Thanks for the feedback. I think that we agree that vectorization on -Os can benefit many programs. Regarding -O2 vs -O3, maybe we should set a higher cost threshold for O2 to increase the likelihood of improving the performance ? We have very few regressions on -O3 as is and with better cost models I believe that we can bring them close to zero, so I am not sure if it can help that much.

Hi, I would like to start a discussion about enabling the loop vectorizer by default for -Os. The loop vectorizer can accelerate many workloads and enabling it for -Os and -O2 has obvious performance benefits. At the same time the loop vectorizer can increase the code size because of two reasons. First, to vectorize some loops we have to keep the original loop around in order to handle the last