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Re: [PATCH][4.3] Deprecate -ftrapv


Paolo Bonzini wrote:
Seems a pity, this feature is really needed for Ada, which requires
efficient overflow checking for signed arithmetic, and it seems
useful for C, where signed overflow is undefined, and it would be
nice to enable trapping.

Right now, Ada uses really horrible double length arithmetic to
do trapping.

It's not the only way to do it though, and it's best to reimplement -ftrapv in terms of GIMPLE.

Right ... from Ada's point of view, it is of course only of limited value to have an implementation of -ftrapv that is equally horrible :-)

I'm for deprecating -ftrapv and reimplementing it. I could mentor a GSOC project for reimplementation of -ftrapv.

Perhaps if the current implementation is too broken, that might be the most constructive approach ...

Paolo


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