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9dc1d0c74e
If an atomic variable is misaligned (and that suspicion is why Clang emits libcalls at all) the runtime support library will have to use a lock to safely access it, with potentially very bad performance consequences. There's a very good chance this is unintentional so it makes sense to issue a warning. Also give it a named group so people can promote it to an error, or disable it if they really don't care. llvm-svn: 330566
28 lines
1017 B
C
28 lines
1017 B
C
// RUN: %clang_cc1 -triple aarch64-linux-gnu %s -emit-llvm -o /dev/null -verify
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typedef struct {
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int a, b;
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} IntPair;
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typedef struct {
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long long a;
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} LongStruct;
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typedef int __attribute__((aligned(1))) unaligned_int;
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void func(IntPair *p) {
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IntPair res;
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__atomic_load(p, &res, 0); // expected-warning {{misaligned or large atomic operation may incur significant performance penalty}}
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__atomic_store(p, &res, 0); // expected-warning {{misaligned or large atomic operation may incur significant performance penalty}}
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__atomic_fetch_add((unaligned_int *)p, 1, 2); // expected-warning {{misaligned or large atomic operation may incur significant performance penalty}}
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__atomic_fetch_sub((unaligned_int *)p, 1, 3); // expected-warning {{misaligned or large atomic operation may incur significant performance penalty}}
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}
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void func1(LongStruct *p) {
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LongStruct res;
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__atomic_load(p, &res, 0);
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__atomic_store(p, &res, 0);
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__atomic_fetch_add((int *)p, 1, 2);
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__atomic_fetch_sub((int *)p, 1, 3);
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}
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