Re: kernel + gcc 4.1 = several problems

From: Horst H. von Brand
Date: Tue Jan 02 2007 - 21:07:38 EST


D. Hazelton <dhazelton@xxxxxxxxx> wrote:

[...]

> None. I didn't file a report on this because I didn't find the big, just
> noted a problem that appears to occur. In this case the call's generated
> seem to wrap loops - something I've never heard of anyone doing.

Example code showing this weirdness?

> These
> *might* be causing the off-by-one that is causing the function to
> re-enter in the middle of an instruction.

If something like this happened, programs would be crashing left and right.

> Seeing this I'd guess that this follows for all system-level code
> generated by 4.1.1

Define "system-level code". What makes it different from, say,
bog-of-the-mill compiler code (yes, gcc compiles itself as part of its
sanity checking)?

> and this is exactly what I was reporting. If you'd
> like I'll go dig up the dumps he posted and post the two related segments
> side-by-side to give you a better example what I'm referring to.

If the related segments show code that is somehow wrong, by all means
report it /with your detailed analysis/ to the compiler people. Just a
warning, gcc is pretty smart in what it does, its code is often surprising
to the unwashed. Also, the C standard is subtle, the error might be in a
unwarranted assumption in the source code.
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