docs/remarks/OMP140.rst

.. _omp140:

Could not internalize function. Some optimizations may not be possible. [OMP140]
====================================================================================================================

This analysis remark indicates that function internalization failed for the
given function. Internalization occurs when a call to a function that ordinarily
has external visibility is replaced with a call to a copy of that function with
only internal visibility. This allows the compiler to make strong static
assertions about the context a function is called in. Without internalization
this analysis would always be invalidated by the possibility of someone calling
the function in a different context outside of the current translation unit.
This is necessary for optimizations like :ref:`OMP111 <omp111>` and :ref:`OMP120
<omp120>`. If a function failed to be internalized it most likely has linkage
that cannot be copied. Internalization is currently only enabled by default for
OpenMP target offloading.

Examples
--------

This will occur for any function declaration that has incompatible linkage.

.. code-block:: c++

   __attribute__((weak)) void setup();

   void foo() {
   #pragma omp target
   {
     setup();
     #pragma omp parallel
     {
       work();
     }
   }
   }

.. code-block:: console

   $ clang++ -fopenmp -fopenmp-targets=nvptx64 -O1 -Rpass-analysis=openmp-opt omp140.cpp
   omp140.cpp:1:1: remark: Could not internalize function. Some optimizations may not
   be possible. [OMP140]
   __attribute__((weak)) void setup() {
   ^

Diagnostic Scope
----------------

OpenMP analysis remark.