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    SubjectRe: Linux 2.6.7-rc2
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    On Mon, 2004-05-31 at 12:53, Linus Torvalds wrote:
    > On Mon, 31 May 2004, Albert Cahalan wrote:
    > >
    > > This would be required because of the -Wno-strict-aliasing
    > > option. For the 2.7.xx kernels, how about we start off by
    > > replacing -Wno-strict-aliasing with -std=gnu99 ? It's been
    > > 5 years since 1999. The "restrict" keyword is useful too.
    >
    > No can do.
    >
    > Aliasing in gcc is so broken (_purely_ type-based and no way to avoid it
    > sanely in older versions) that it's not going to happen.
    >
    > When we can depend on everybody having gcc-3.3+ something, and that one
    > properly supports the "may_alias" attribute, we may change that.

    By the time Linux 2.8.0 is out, gcc-3.3+ should be
    a perfectly reasonable requirement.

    In the mean time, adding may_alias as needed would be
    a good idea.

    If all this were behind CONFIG_BROKEN, it sure wouldn't
    hurt even today. People might as well get started.
    The compiler will keep being pessimistic and dumb until
    the -Wno-strict-aliasing option is dropped.

    > "restrict" is pretty much useless. It just weakens the already too-weak
    > alias rules of standard gcc.

    It's easiest to use on function parameters. This helps
    the optimizer without being a mind-warping excercise.


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