[cfe-dev] __builtin_nan support

[Nate Begeman]

On May 19, 2008, at 12:06 PM, Eli Friedman wrote:

> On Mon, May 19, 2008 at 11:02 AM, Nate Begeman <natebegeman at mac.com>  
> wrote:
>> Attached patch implements __builtin_nan, __builtin_nanf, and  
>> __builtin_nanl.
>
> @@ -58,6 +57,10 @@
>     if (SemaBuiltinUnorderedCompare(TheCall.get()))
>       return true;
>     return TheCall.take();
> +  case Builtin::BI__builtin_nan:
> +  case Builtin::BI__builtin_nanf:
> +  case Builtin::BI__builtin_nanl:
> +    return SemaBuiltinNaN(FnInfo->getBuiltinID(), TheCall.get());
>   case Builtin::BI__builtin_shufflevector:
>     return SemaBuiltinShuffleVector(TheCall.get());
>   }
>
> This is unsafe; in the case where SemaBuiltinNaN doesn't find a string
> literal, you end up with a dangling pointer.

Sure enough, need a take vs. get

>
>
> +      llvm::APInt Val(64, 0x7ff8000000000000ULL, false);
> +
> +      char *endp = 0;
> +      uint64_t Significand = strtoull(data, &endp, 0);
>
> Windows doesn't have strtoull.

What's the suggested replacement?

Nate