Re: [RFC] CFLAGS paragraph for the GWN
Duncan <1i5t5.duncan <at> cox.net>
2006-10-01 11:23:37 GMT
Ryan Hill <dirtyepic.sk <at> gmail.com> posted efmrae$jff$1 <at> sea.gmane.org,
excerpted below, on Sat, 30 Sep 2006 16:37:05 -0600:
> If you want flags that just break
> stuff with 4.1 you can include -ftree-vectorize.
Could you point me at some info on this one (-ftree-vectorize)? It came
up on the amd64 list a week or so ago, when someone asked what I thought
of it and why I didn't have it in my cflags (which I had just explained).
I said I didn't know enough about it to make a case either way, and as
such, didn't choose to use it. However, after a bit of discussion, I
decided to add it to my cflags on a very experimental basis. I haven't
experienced any issues with it, but then I haven't done any major
compiling since then either, only the routine updates.
If I had rather more info on it, therefore, particularly on why it might
break stuff, I'd be able to pass it on, telling the list and in particular
the guy that asked, why it's NOT a good thing to use. Thus, point me at
it, if you got it. Even something as simple as a list of bugs traced to
it would be useful as something I could point at, if that's what you are
basing your remark on.
Or does the problem not necessarily apply to amd64? Even knowing that
would be useful. I simply don't know anything much at all about it, beyond
a generally vague idea that it means using mmx/sse/whatever vector
instructions to parallelize loops.