[CodeGen] Remove atomic sugar from record types in isSafeToConvert

We failed to see that we should have deferred the creation of a type
which references a type currently under construction because of atomic
sugar.

This fixes PR23985.

llvm-svn: 240989

2 files changed, 25 insertions, 7 deletions

diff --git a/clang/lib/CodeGen/CodeGenTypes.cpp b/clang/lib/CodeGen/CodeGenTypes.cpp
index e0f926cabd7..a4a8654eb36 100644
--- a/clang/lib/CodeGen/CodeGenTypes.cpp
+++ b/clang/lib/CodeGen/CodeGenTypes.cpp
@@ -154,14 +154,16 @@ isSafeToConvert(const RecordDecl *RD, CodeGenTypes &CGT,
 static bool
 isSafeToConvert(QualType T, CodeGenTypes &CGT,
                 llvm::SmallPtrSet<const RecordDecl*, 16> &AlreadyChecked) {
-  T = T.getCanonicalType();
-  
+  // Strip off atomic type sugar.
+  if (const auto *AT = T->getAs<AtomicType>())
+    T = AT->getValueType();
+
   // If this is a record, check it.
-  if (const RecordType *RT = dyn_cast<RecordType>(T))
+  if (const auto *RT = T->getAs<RecordType>())
     return isSafeToConvert(RT->getDecl(), CGT, AlreadyChecked);
-  
+
   // If this is an array, check the elements, which are embedded inline.
-  if (const ArrayType *AT = dyn_cast<ArrayType>(T))
+  if (const auto *AT = CGT.getContext().getAsArrayType(T))
     return isSafeToConvert(AT->getElementType(), CGT, AlreadyChecked);
 
   // Otherwise, there is no concern about transforming this.  We only care about
diff --git a/clang/test/CodeGen/c11atomics.c b/clang/test/CodeGen/c11atomics.c
index a35eef94264..d1e4478d7ec 100644
--- a/clang/test/CodeGen/c11atomics.c
+++ b/clang/test/CodeGen/c11atomics.c
@@ -12,8 +12,24 @@
 // they're sufficiently rare that it's not worth making sure that the semantics
 // are correct.
 
-// CHECK: @testStructGlobal = global {{.*}} { i16 1, i16 2, i16 3, i16 4 }
-// CHECK: @testPromotedStructGlobal = global {{.*}} { %{{.*}} { i16 1, i16 2, i16 3 }, [2 x i8] zeroinitializer }
+struct elem;
+
+struct ptr {
+    struct elem *ptr;
+};
+// CHECK-DAG: %struct.ptr = type { %struct.elem* }
+
+struct elem {
+    _Atomic(struct ptr) link;
+};
+// CHECK-DAG: %struct.elem = type { %struct.ptr }
+
+struct ptr object;
+// CHECK-DAG: @object = common global %struct.ptr zeroinitializer
+
+// CHECK-DAG: @testStructGlobal = global {{.*}} { i16 1, i16 2, i16 3, i16 4 }
+// CHECK-DAG: @testPromotedStructGlobal = global {{.*}} { %{{.*}} { i16 1, i16 2, i16 3 }, [2 x i8] zeroinitializer }
+
 
 typedef int __attribute__((vector_size(16))) vector;