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Re: [PATCH, ARM] Avoid pulling in unwinder for 64-bit division

Julian Brown <> writes:

> On Wed, 28 Oct 2009 07:49:18 -0700
> Ian Lance Taylor <> wrote:
>> Julian Brown <> writes:
>> > This patch sets compilation flags for the relevant parts of libgcc
>> > on ARM such that the unwinder is not unnecessarily pulled in to the
>> > linked executable when 64-bit division is used. This can be quite a
>> > significant space saving on bare-metal systems.
>> I think the question here is what should happen when a division by
>> zero occurs.  I believe that is why we currently pass
>> -fnon-call-exceptions.  What happens on ARM if you divide by zero?  In
>> particular, what happens if you divide by zero in a program which is
>> itself compiled with -fnon-call-exceptions, and which expects to catch
>> a division by zero exception?  Do 32-bit divisions and 64-bit
>> divisions behave in the same way?
> A follow-up patch to address division-by-zero problems (the handling
> not being ARM EABI-compliant) is here:
> (These patches both date from some time ago: I believe throwing an
> exception from a divide-by-zero handler should work correctly after
> the latter patch is applied, but I've not tested that recently.)

Well, I'll let the ARM maintainers decide about that patch.

Looking again at
I don't understand why you want to change or

I'll approve the change to libgcc/ if the ARM maintainers
approve the rest of the patch.


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