Avoid multiple atomic builtin declaration.

llvm-svn: 164454

clang/lib/Sema/SemaChecking.cpp

@@ -1198,10 +1198,19 @@ Sema::SemaBuiltinAtomicOverloaded(ExprResult TheCallResult) {
   // concrete integer type we should convert to is.
   unsigned NewBuiltinID = BuiltinIndices[BuiltinIndex][SizeIndex];
   const char *NewBuiltinName = Context.BuiltinInfo.GetName(NewBuiltinID);
-  IdentifierInfo *NewBuiltinII = PP.getIdentifierInfo(NewBuiltinName);
-  FunctionDecl *NewBuiltinDecl =
-    cast<FunctionDecl>(LazilyCreateBuiltin(NewBuiltinII, NewBuiltinID,
-                                           TUScope, false, DRE->getLocStart()));
+  FunctionDecl *NewBuiltinDecl;
+  if (NewBuiltinID == BuiltinID)
+    NewBuiltinDecl = FDecl;
+  else {
+    // Perform builtin lookup to avoid redeclaring it.
+    DeclarationName DN(&Context.Idents.get(NewBuiltinName));
+    LookupResult Res(*this, DN, DRE->getLocStart(), LookupOrdinaryName);
+    LookupName(Res, TUScope, /*AllowBuiltinCreation=*/true);
+    assert(Res.getFoundDecl());
+    NewBuiltinDecl = dyn_cast<FunctionDecl>(Res.getFoundDecl());
+    if (NewBuiltinDecl == 0)
+      return ExprError();
+  }
 
   // The first argument --- the pointer --- has a fixed type; we
   // deduce the types of the rest of the arguments accordingly.  Walk

clang/test/Sema/builtins.c

@@ -51,6 +51,20 @@ void test9(short v) {
   }
 }
 
+// overloaded atomics should be declared only once.
+void test9_1(volatile int* ptr, int val) {
+  __sync_fetch_and_add_4(ptr, val);
+}
+void test9_2(volatile int* ptr, int val) {
+  __sync_fetch_and_add(ptr, val);
+}
+void test9_3(volatile int* ptr, int val) {
+  __sync_fetch_and_add_4(ptr, val);
+  __sync_fetch_and_add(ptr, val);
+  __sync_fetch_and_add(ptr, val);
+  __sync_fetch_and_add_4(ptr, val);
+  __sync_fetch_and_add_4(ptr, val);
+}
 
 // rdar://7236819
 void test10(void) __attribute__((noreturn));