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Re: [PATCH][4.3] Deprecate -ftrapv



Well presumably one would want to use target dependent stuff for
detecting overflow where it exists (sticky overflow bits on
power, O flag on PC, trapping add on MIPS etc).

On the whole I think you'd want to benefit from tree-ssa optimizing overflow checks where possible (including optimizing them away with VRP), if you hope for a -ftrapv that could be turned on by default for Ada with performance impact as small as possible. That would suggest back ends matching overflow-check patterns and converting them into such
instructions.

Yes, fully fully agreed.


Paolo


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