[LLVMdev] Integer divide by zero

[Cameron McInally]

On Sun, Apr 7, 2013 at 1:23 PM, Duncan Sands <baldrick at free.fr> wrote:
...

> If you want a trap you are going to have to (IMO) output IR
> instructions rather than a constant expression.  For example you can
> output the
> equivalent of
>   if (x == 0)
>      llvm.trap() // or maybe some special trap routine
>   y = whatever/x
>   ... use y ...
> rather than the constant expression "whatever/x".  If the optimizers can
> prove
> that x is never zero then this will be sunk back into a constant
> expression (if
> "whatever" is a constant expression).
>

Ah, that's super interesting. I'll have to give it some more thought.
Thanks for this, Duncan.

My knee-jerk reaction is that emulating hardware behaviour in software
should be avoided. At least in this specific case.

Thanks again,
Cameron
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