[cfe-dev] Traps for signed arithmetic overflow

[Vincent Lefevre via cfe-dev]

On 2018-11-24 08:26:39 -0600, Segher Boessenkool wrote:
> -fsanitize=undefined instruments undefined behaviour.  This isn't undefined
> behaviour.  Also, both -fsanitize=signed-integer-overflow and -ftrapv are
> documented to only do things for addition, subtraction, and multiplication
> (not conversion).
> 
> If you want a warning for implementation-defined behaviour, sure, not many
> people will oppose that (it will warn all of the time, making it not very
> useful, but hey).  Still, it should be a separate option.  Implementation-
> defined behaviour is not undefined, after all.

It is a design flaw in GCC, which should have chosen the
"implementation-defined signal" solution, as allowed by the
C standard. This would be much more secure.

-- 
Vincent Lefèvre <vincent at vinc17.net> - Web: <https://www.vinc17.net/>
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