Gentoo Archives: gentoo-dev

From: Ryan Hill <×××××.com>
To: gentoo-dev@l.g.o
Subject: [gentoo-dev] Re: [RFC] CFLAGS paragraph for the GWN
Date: Sun, 01 Oct 2006 18:06:20
Message-Id: efovnn$sm8$
In Reply to: [gentoo-dev] Re: [RFC] CFLAGS paragraph for the GWN by Duncan <>
Duncan wrote:

> 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. They've fixed quite a few of the ICE's since last I looked, though there's more than a couple that went in after 4.1.1. 4.2 is a little better, but I'm having enough trouble getting it to build things properly _without_ using any fancy flags right now. ;p See for some real-world examples.
> 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.
I'd say that there's more ICE's on i686-pc-linux-gnu than x86_64-*-linux-gnu, but there's still enough. Luckily Halcy0n was really good for reducing testcases and pushing them upstream, so a lot of these issues got fixed at the source. --de.


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Subject Author
[gentoo-dev] Re: [RFC] CFLAGS paragraph for the GWN Duncan <1i5t5.duncan@×××.net>