Adopt upstream OpenMP flag improvements (approved in llvm#178914)#1332
Adopt upstream OpenMP flag improvements (approved in llvm#178914)#1332nicebert wants to merge 4 commits intoamd-stagingfrom
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Add -fno-openmp-assume-no-thread-state and -fno-openmp-assume-no-nested-parallelism flags to allow explicit disabling of these assumptions. Currently these flags only exist as MarshallingInfoNegativeFlag which doesn't generate separate OPT_* constants needed for driver code. Making them standalone flags enables proper last-wins behavior and allows them to be used in implication logic.
Add a new flag to indicate that the OpenMP runtime can ignore environment variables during code generation for GPU offload. This allows the compiler to generate more efficient GPU code by assuming environment variables won't affect runtime behavior, enabling optimizations like skipping runtime checks and eliminating conditional branches. The flag includes both positive and negative variants and will be used by the -fopenmp-target-fast meta-flag.
Add meta-flag that implies multiple GPU optimization flags: - -fopenmp-target-ignore-env-vars - -fopenmp-assume-no-thread-state - -fopenmp-assume-no-nested-parallelism The flag is automatically enabled by -Ofast and can be explicitly disabled with -fno-openmp-target-fast. Individual implied flags can be selectively overridden while keeping others enabled.
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…adopt-upstream-openmp # Conflicts: # clang/include/clang/Options/Options.td # clang/lib/Driver/ToolChains/Clang.cpp # clang/test/Driver/openmp-target-fast-flag.c
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This PR adopts OpenMP flag improvements that have been approved for upstream LLVM (PR llvm#178914) but haven't merged yet.
Changes:
Upstream Reference: llvm#178914