jfb created this revision. jfb added a reviewer: dexonsmith. Herald added a subscriber: cfe-commits.
Using _Atomic to do implicit load / store is just a seq_cst atomic_load / atomic_store. Stores currently assert in Sema::ImpCastExprToType with 'can't implicitly cast lvalue to rvalue with this cast kind', but that's erroneous. The codegen is fine as the test shows. While investigating I found that Richard had found the problem here: https://reviews.llvm.org/D46112#1113557 rdar://problem/40347123 Repository: rC Clang https://reviews.llvm.org/D49458 Files: lib/Sema/Sema.cpp test/CodeGen/atomic-ops.c Index: test/CodeGen/atomic-ops.c =================================================================== --- test/CodeGen/atomic-ops.c +++ test/CodeGen/atomic-ops.c @@ -183,6 +183,18 @@ double x; }; +void implicit_store(_Atomic(struct S) *a, struct S s) { + // CHECK-LABEL: @implicit_store( + // CHECK: store atomic i64 %{{.*}}, i64* %{{.*}} seq_cst, align 8 + *a = s; +} + +struct S implicit_load(_Atomic(struct S) *a) { + // CHECK-LABEL: @implicit_load( + // CHECK: load atomic i64, i64* %{{.*}} seq_cst, align 8 + return *a; +} + struct S fd1(struct S *a) { // CHECK-LABEL: @fd1 // CHECK: [[RETVAL:%.*]] = alloca %struct.S, align 4 Index: lib/Sema/Sema.cpp =================================================================== --- lib/Sema/Sema.cpp +++ lib/Sema/Sema.cpp @@ -481,6 +481,7 @@ case CK_ArrayToPointerDecay: case CK_FunctionToPointerDecay: case CK_ToVoid: + case CK_NonAtomicToAtomic: break; } }
Index: test/CodeGen/atomic-ops.c =================================================================== --- test/CodeGen/atomic-ops.c +++ test/CodeGen/atomic-ops.c @@ -183,6 +183,18 @@ double x; }; +void implicit_store(_Atomic(struct S) *a, struct S s) { + // CHECK-LABEL: @implicit_store( + // CHECK: store atomic i64 %{{.*}}, i64* %{{.*}} seq_cst, align 8 + *a = s; +} + +struct S implicit_load(_Atomic(struct S) *a) { + // CHECK-LABEL: @implicit_load( + // CHECK: load atomic i64, i64* %{{.*}} seq_cst, align 8 + return *a; +} + struct S fd1(struct S *a) { // CHECK-LABEL: @fd1 // CHECK: [[RETVAL:%.*]] = alloca %struct.S, align 4 Index: lib/Sema/Sema.cpp =================================================================== --- lib/Sema/Sema.cpp +++ lib/Sema/Sema.cpp @@ -481,6 +481,7 @@ case CK_ArrayToPointerDecay: case CK_FunctionToPointerDecay: case CK_ToVoid: + case CK_NonAtomicToAtomic: break; } }
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