OpenMP task

[peihunglin]

I was able to use the Archer in tr4 branch with clang 4.0.1 to find race in this benchmark:
https://github.com/LLNL/dataracebench/blob/master/micro-benchmarks/taskdependmissing-orig-yes.c
But a later version of Archer with clang 3.9.1 (installed on LLNL LC system) does not find race in this same benchmark. Is that caused by different clang version or some other issue?

[jprotze]

This benchmark has a high chance to schedule both tasks on the same thread. In that case the tool currently will not detect a race. Only in the rare case where the task is actually scheduled on different threads, the tool can identify the race.