[LLVMdev] '___ltsf2' could not be resolved - iOS/ARM cross compile

Tim Northover
Fri, 05 Sep 2014 12:11:35 -0000

On 5 September 2014 12:32, mondi <mondi at dyskinetic.com>
wrote:
> I’m building llvm for my iOS devices, and all seems to work well, until I
try to execute the results:
>
> LLVM ERROR: Program used external function '___ltsf2' which could
not be resolved!

That's the software floating-point less-than operator. It shouldn't be
used if you're compiling for iOS since there are real instructions to
do the job.

If this is for a custom front-end, you're going to have to set the
triple and CPU features manually. You might get away with just setting
the triple to something like "thumbv7s-apple-ios7.0", at least for
initial experiments. But longer term, there are quite a few subtleties
you're likely to have to contend with.

Cheers.

Tim.