[lkml]   [2003]   [Feb]   [26]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
Messages in this thread
    SubjectRe: Invalid compilation without -fno-strict-aliasing
    In article <>,
    Jean Tourrilhes <> wrote:
    > It looks like a compiler bug to me...

    Why do you think the kernel uses "-fno-strict-aliasing"?

    The gcc people are more interested in trying to find out what can be
    allowed by the c99 specs than about making things actually _work_. The
    aliasing code in particular is not even worth enabling, it's just not
    possible to sanely tell gcc when some things can alias.

    > Some users have complained that when the following code is
    >compiled without the -fno-strict-aliasing, the order of the write and
    >memcpy is inverted (which mean a bogus len is mem-copied into the

    The "problem" is that we inline the memcpy(), at which point gcc won't
    care about the fact that it can alias, so they'll just re-order
    everything and claim it's out own fault. Even though there is no sane
    way for us to even tell gcc about it.

    I tried to get a sane way a few years ago, and the gcc developers really
    didn't care about the real world in this area. I'd be surprised if that
    had changed, judging by the replies I have already seen.

    I'm not going to bother to fight it.

    To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
    the body of a message to
    More majordomo info at
    Please read the FAQ at

     \ /
      Last update: 2005-03-22 13:33    [W:0.020 / U:169.904 seconds]
    ©2003-2016 Jasper Spaans. hosted at Digital OceanAdvertise on this site