[OPENMP] Codegen for 'lastprivate' clause in 'sections' directive.
#pragma omp sections lastprivate(<var>)
<BODY>;
This construct is translated into something like:
<last_iter> = alloca i32
<init for lastprivates>;
<last_iter> = 0
; No initializer for simple variables or a default constructor is called for objects.
; For arrays perform element by element initialization by the call of the default constructor.
...
OMP_FOR_START(...,<last_iter>, ..); sets <last_iter> to 1 if this is the last iteration.
<BODY>
...
OMP_FOR_END
if (<last_iter> != 0) {
<final copy for lastprivate>; Update original variable with the lastprivate value.
}
call __kmpc_cancel_barrier() ; an implicit barrier to avoid possible data race.
If there is only one section, there is no special code generation, original shared variables are used + barrier is emitted at the end of the directive.
Differential Revision: http://reviews.llvm.org/D9240
git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@235834 91177308-0d34-0410-b5e6-96231b3b80d8
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