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

Hi there,

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!

This appears to be part of compiler-rt which as far as I can see should be built / linked automatically when installed correctly? Am I missing something obvious?



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.



It is indeed for a custom frontend, and given that I’m compiling with the very generic “arm-apple-darwin” at the moment, that makes a lot of sense. I’ll try some more specific targets and see what difference it makes