forked from pool/llvm14
23 lines
795 B
Diff
23 lines
795 B
Diff
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Better detect 64bit atomics support.
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It appears that on i586 std::atomic<uint64_t>::load is compiled into
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instruction, but std::atomic<double>::load uses __atomic_load_8. This must
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be detected so the build system links it to libatomic.
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Index: llvm-12.0.0.src/cmake/modules/CheckAtomic.cmake
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===================================================================
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--- llvm-12.0.0.src.orig/cmake/modules/CheckAtomic.cmake
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+++ llvm-12.0.0.src/cmake/modules/CheckAtomic.cmake
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@@ -30,9 +30,12 @@ function(check_working_cxx_atomics64 var
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#include <atomic>
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#include <cstdint>
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std::atomic<uint64_t> x (0);
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+std::atomic<double> y (0);
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int main() {
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uint64_t i = x.load(std::memory_order_relaxed);
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+ double j = y.load(std::memory_order_relaxed);
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(void)i;
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+ (void)j;
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return 0;
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}
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" ${varname})
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