[OpenMP] Fix mapping of artificial variables (PR94874)

[OpenMP] Fix mapping of artificial variables (PR94874)

gcc/c-family/ChangeLog:

	* c-common.h (c_omp_predetermined_mapping): Declare.
	* c-omp.c (c_omp_predetermined_mapping): New.

gcc/c/ChangeLog:

	* c-objc-common.h (LANG_HOOKS_OMP_PREDETERMINED_MAPPING): Redefine.

gcc/cp/ChangeLog:

	* cp-gimplify.c (cxx_omp_predetermined_mapping): New.
	* cp-objcp-common.h (LANG_HOOKS_OMP_PREDETERMINED_MAPPING): Redfine.
	* cp-tree.h (cxx_omp_predetermined_mapping): Declare.

gcc/fortran/ChangeLog:

	* f95-lang.c (LANG_HOOKS_OMP_PREDETERMINED_MAPPING): Redefine.
	* trans-openmp.c (gfc_omp_predetermined_mapping): New.
	* trans.h (gfc_omp_predetermined_mapping): Declare.

gcc/ChangeLog:

	* gimplify.c (omp_notice_variable): Use new hook.
	* langhooks-def.h (lhd_omp_predetermined_mapping): Declare.
	(LANG_HOOKS_OMP_PREDETERMINED_MAPPING): Define
	(LANG_HOOKS_DECLS): Add it.
	* langhooks.c (lhd_omp_predetermined_sharing): Remove bogus unused attr.
	(lhd_omp_predetermined_mapping): New.
	* langhooks.h (struct lang_hooks_for_decls): Add new hook.

gcc/testsuite/ChangeLog
2020-06-03  Thomas Schwinge  <thomas@codesourcery.com>
	    Tobias Burnus  <tobias@codesourcery.com>

	PR middle-end/94874
	* c-c++-common/gomp/pr94874.c: New.