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From: "burnus at gcc dot gnu.org" <gcc-bugzilla@gcc.gnu.org>
To: gcc-bugs@gcc.gnu.org
Subject: [Bug tree-optimization/90591] Avoid unnecessary data transfer out of
 OMP construct
Date: Tue, 05 May 2020 14:16:28 +0000
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X-Bugzilla-Component: tree-optimization
X-Bugzilla-Version: 10.0
X-Bugzilla-Keywords: openacc, openmp
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https://gcc.gnu.org/bugzilla/show_bug.cgi?id=3D90591

--- Comment #5 from Tobias Burnus <burnus at gcc dot gnu.org> ---
Somewhat related: In terms of OpenMP (to be refined in the spec), the follo=
wing
applies (in order to work both with shared + nonshared memory):

  int x =3D 5;
  #pragma omp target map(from:x)
    x =3D 7;
  printf("%f\n", x);

This code is invalid =E2=80=93 which means that the compiler could use this=
 for
optimization and it probably should warn that "x" is used uninitialized.=