This is the mail archive of the
mailing list for the GCC project.
- From: Richard Biener <richard dot guenther at gmail dot com>
- To: Jakub Jelinek <jakub at redhat dot com>
- Cc: Hendrik Greving <hendrik dot greving dot intel at gmail dot com>, GCC Development <gcc at gcc dot gnu dot org>
- Date: Mon, 11 Nov 2013 14:13:24 +0100
- Subject: Re: Vectorizer/alignment
- Authentication-results: sourceware.org; auth=none
- References: <CANc4vhqiMCbkHHbKjY-tPmvi7iU4wXP4Jf_4S83jGTBJTCCi3Q at mail dot gmail dot com> <3a0cd1a6-76c9-4539-9830-8ddbf5405db3 at email dot android dot com> <CANc4vhobNfNQkm1HdFjL5c1tUnxOiNyumFG5XUCb71LRxBdU5g at mail dot gmail dot com> <CAFiYyc0G5vCtQp9Zy-xUyfeK6475FrVn++yacW1kB_v5H+nTjQ at mail dot gmail dot com> <20131111113922 dot GW27813 at tucnak dot zalov dot cz>
On Mon, Nov 11, 2013 at 12:39 PM, Jakub Jelinek <email@example.com> wrote:
> On Mon, Nov 11, 2013 at 12:29:29PM +0100, Richard Biener wrote:
>> On Fri, Nov 8, 2013 at 6:51 PM, Hendrik Greving
>> <firstname.lastname@example.org> wrote:
>> > That didn't do it. What was the rationale w.r.t. to the relation
>> > between the vectorized sequenced and/or the alignment (I think these
>> > things are actually 2 separate things..) and the common block?!
>> We cannot adjust the alignment of a common block as we don't know
>> which common block the linker will pick in the end. We can (and do)
>> adjust the alignment of global variables though. And C++ defaults
>> to -fno-common.
>> In general when asking optimization questions it helps to provide
>> a testcase that can be compiled - otherwise you just provoke
>> random guesses (like mine) ;)
> Well, we had the discussion about turning -fno-common by default for C as
> well, I think it wouldn't hurt and let people use -fcommon if they need it.
Yeah, so ... shall we just do it? Maybe just for a selected set of
targets (based on OS?)?