compnerd created this revision. compnerd added reviewers: craig.topper, srhines. Herald added a subscriber: jfb. Herald added a project: clang.
The android target assumes that for the x86_64 target, the CPU supports SSE4.2 and `popcnt`. This implies that the CPU is Nehalem or newer. This should be sufficiently new to provide the double word compare and exchange instruction. This allows us to directly lower `__sync_val_compare_and_swap_16` to a `cmpxchg16b`. It appears that the libatomic in android's NDK does not provide the implementation for lowering calls to the library function. Repository: rC Clang https://reviews.llvm.org/D63774 Files: lib/Driver/ToolChains/Arch/X86.cpp Index: lib/Driver/ToolChains/Arch/X86.cpp =================================================================== --- lib/Driver/ToolChains/Arch/X86.cpp +++ lib/Driver/ToolChains/Arch/X86.cpp @@ -135,6 +135,7 @@ if (ArchType == llvm::Triple::x86_64) { Features.push_back("+sse4.2"); Features.push_back("+popcnt"); + Features.push_back("+mcx16"); } else Features.push_back("+ssse3"); }
Index: lib/Driver/ToolChains/Arch/X86.cpp =================================================================== --- lib/Driver/ToolChains/Arch/X86.cpp +++ lib/Driver/ToolChains/Arch/X86.cpp @@ -135,6 +135,7 @@ if (ArchType == llvm::Triple::x86_64) { Features.push_back("+sse4.2"); Features.push_back("+popcnt"); + Features.push_back("+mcx16"); } else Features.push_back("+ssse3"); }
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