Commit 38e89533 authored Apr 16, 2015 by Alexey Bataev

[OPENMP] Codegen for 'lastprivate' clause in 'for' directive.

#pragma omp for lastprivate(<var>)
for (i = a; i < b; ++b)
  <BODY>;

This construct is translated into something like:

  <last_iter> = alloca i32
  <lastprivate_var> = alloca <type>
  <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) {
    <var> = <lastprivate_var> ; Update original variable with the lastprivate value.
  }
  call __kmpc_cancel_barrier() ; an implicit barrier to avoid possible data race.

Differential Revision: http://reviews.llvm.org/D8658

llvm-svn: 235074

parent 4421ac6b

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