[clang] [OpenMP] Introduce -fopenmp-force-usm flag (PR #75468)

[Joseph Huber via cfe-commits]

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@@ -3381,6 +3381,8 @@ def fopenmp_cuda_blocks_per_sm_EQ : Joined<["-"], "fopenmp-cuda-blocks-per-sm=">
   Flags<[NoArgumentUnused, HelpHidden]>, Visibility<[ClangOption, CC1Option]>;
 def fopenmp_cuda_teams_reduction_recs_num_EQ : Joined<["-"], "fopenmp-cuda-teams-reduction-recs-num=">, Group<f_Group>,
   Flags<[NoArgumentUnused, HelpHidden]>, Visibility<[ClangOption, CC1Option]>;
+def fopenmp_force_usm : Flag<["-"], "fopenmp-force-usm">, Group<f_Group>,
+  Flags<[NoArgumentUnused, HelpHidden]>, Visibility<[CC1Option]>;
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jhuber6 wrote:

No, it would just override the flag before it. E.g. `-fopenmp-force-usm -fno-openmp-force-usm` would return to not having it on.

https://github.com/llvm/llvm-project/pull/75468