Will -heap-arrays flag be ignored if -openmp is used for compilation?
BTW, will -heap-array cause any issue with thread-safety?
No it won't be ignored. It should not cause thread safety issues. The pointer to the storage is per-thread and threads don't share the same heap-allocated temporary. (If there is a conflict, that's a bug we want to know about.)
Thanks for your reply. But here is what I found from this doc.
-openmp Interaction with –heap-arrays
• -openmp will cause the compiler use slightly different behavior for –heap-arrays
• Procedure local data with –heap-arrays and –openmp are STACK allocated (therefore, thread-safe) – must explicitly override with SAVE attribute to get on heap • Automatic arrays: descriptor allocated on stack, data allocated in heap (thus, also thread-safe).
• OpenMP puts a heavy load on stack, threadprivate variables need stack allocation
• Use stack-increasing methods – you will need much more stack than an non-OpenMP application
So for automatic and temporary data, what is the actual behavior for Intel comipler "intel/compiler-14.0.1/bin/ifort"
Is it possible to have a test program to validate where the automatic and temporary data is allocated?
I'd like to test for -heap-array with and without -openmp?
I don't know what the 14.0 compiler's behavior is and don't recommend using that unsupported version. Ideally you'd want to avoid anything that creates temporary array copies.
That presentation you found is a decade old.