[patch] enabling vectorization by default at -O3

Jan Hubicka hubicka@ucw.cz
Thu Sep 6 12:20:00 GMT 2007


Hi,
> 
> Hi,
> 
> It has recently been proposed/requested that the vectorizer be turned on by
> default with -O3.  I think it's a good idea in principle, though I don't
> know how bad the impact on the compiler's stability would be in the
> immediate term. We could give it a try, and decide to turn it off again if
> things don't stabilize quickly enough. This will probably require a joint
> effort, so it makes sense to go into this adventure only if people are
> interested in giving this a try (i.e. help!). In terms of stability I can
> currently report that:

I definitly like the idea of enabling more loop optimization stuff at
-O3 in general.  If the vectorizer is able to trottle down itself on
cold loops or loops not iterating much at average, I would suggest
enabling it also with -fprofile-use.

Honza



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