[LLVMdev] Floating-Point Overflow check

Dale Johannesen dalej at apple.com
Fri Jul 23 10:41:10 PDT 2010


On Jul 23, 2010, at 7:20 AMPDT, Steffen Gei├činger wrote:

> Hi,
>
> i need to check if an overflow of an floating-point arithmetic  
> operation occured.
> Currently I'm doing something like this (for addition):
>
> (LHS > 0 && RHS > 0 && sum <= 0)  || (LHS < 0 && RHS < 0 && sum >= 0)
>
> This is checked for every addition.
> Is there a more efficient way like the intrisic for int overflow?
> How is it possible to raise a signal like SIGFPE?

If you're talking about compile-time arithmetic, you should be using  
the APFloat library, which figures this out for you.

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