-fopenmp turns on OpenMP support and links libiomp5 as OpenMP library. Also there is -fopenmp={libiomp5|libgomp} option that allows to override effect of -fopenmp and link libgomp library (if -fopenmp=libgomp is specified).
Differential Revision: http://reviews.llvm.org/D9736
llvm-svn: 237769
If condition evaluates to true, the code executes task by calling @__kmpc_omp_task() runtime function.
If condition evaluates to false, the code executes serial version of the code by executing the following code:
call void @__kmpc_omp_task_begin_if0(<loc>, <threadid>, <task_t_ptr, returned by @__kmpc_omp_task_alloc()>);
proxy_task_entry(<gtid>, <task_t_ptr, returned by @__kmpc_omp_task_alloc()>);
call void @__kmpc_omp_task_complete_if0(<loc>, <threadid>, <task_t_ptr, returned by @__kmpc_omp_task_alloc()>);
Also it checks if the condition is constant and if it is constant it evaluates its value and then generates either parallel version of the code (if the condition evaluates to true), or the serial version of the code (if the condition evaluates to false).
Differential Revision: http://reviews.llvm.org/D9143
llvm-svn: 235507
Alexey Bataev