[LLVMdev] libiomp, not libgomp as default library linked with -fopenmp

Ed Maste
2015-04-30T15:59:47Z

On 30 April 2015 at 10:06, Hal Finkel <hfinkel at anl.gov>
wrote:
>>
>> I'd like to resurrect the discussion on replacing libgomp with
>> libiomp as the default OpenMP runtime library linked with -fopenmp.
>>
>>
>> For reference, the previous discussion is accessible there:
>>
http://lists.cs.uiuc.edu/pipermail/cfe-commits/Week-of-Mon-20140217/thread.html#99461
>>
>>
>> We are very close to getting *full* OpenMP 3.1 specification
>> supported in clang (only one (!) clause is not implemented yet, and
>> the patch is already sent for review today:
>> http://reviews.llvm.org/D9370 ). This implementation generates Intel
>> API library calls; thus, it can't be used with libgomp and it is
>> simply logical to link a compatible runtime (libiomp) instead.
>
> To be clear, this is now LLVM's OpenMP runtime (not just Intel's),
and has been ported to several platforms in addition to x86 (PowerPC, ARM).

It looks like openmp/runtime/README.txt could use an update to clarify
this status. The title is "README for the Intel(R) OpenMP* Runtime
Library" and there's a of supported Intel architectures -- this gives
a somewhat different impression than what's described in this thread.

That said, I would also be happy to see the default switched to libiomp.