[Clang] skip warnings for constructors marked with the [[noreturn]] attribute

clang/docs/ReleaseNotes.rst

@@ -555,6 +555,8 @@ Improvements to Clang's diagnostics
       getS(); // Now diagnoses "Reason 2", previously diagnoses "Reason 1"
     }
 
+- Clang now omits warnings for constructors marked with the ``[[noreturn]]`` attribute (#GH63009).
+
 Improvements to Clang's time-trace
 ----------------------------------
 

clang/lib/Analysis/CFG.cpp

@@ -4889,16 +4889,21 @@ CFGBlock *CFGBuilder::VisitCXXFunctionalCastExpr(CXXFunctionalCastExpr *E,
   return Visit(E->getSubExpr(), asc);
 }
 
-CFGBlock *CFGBuilder::VisitCXXTemporaryObjectExpr(CXXTemporaryObjectExpr *C,
+CFGBlock *CFGBuilder::VisitCXXTemporaryObjectExpr(CXXTemporaryObjectExpr *E,
                                                   AddStmtChoice asc) {
   // If the constructor takes objects as arguments by value, we need to properly
   // construct these objects. Construction contexts we find here aren't for the
   // constructor C, they're for its arguments only.
-  findConstructionContextsForArguments(C);
+  findConstructionContextsForArguments(E);
 
-  autoCreateBlock();
-  appendConstructor(Block, C);
-  return VisitChildren(C);
+  CXXConstructorDecl *C = E->getConstructor();
+  if (C && C->isNoReturn())
+    Block = createNoReturnBlock();
+  else
+    autoCreateBlock();
+
+  appendConstructor(Block, E);
+  return VisitChildren(E);
 }
 
 CFGBlock *CFGBuilder::VisitImplicitCastExpr(ImplicitCastExpr *E,

clang/test/CXX/dcl.dcl/dcl.attr/dcl.attr.noreturn/p1.cpp

@@ -49,3 +49,15 @@ void check() {
   test_type(g);
   test_type(h); // expected-note {{instantiation}}
 }
+
+namespace GH63009 {
+struct S {
+  [[noreturn]] S() { throw int {}; }
+};
+
+int test_no_return_constructor() { S(); } // ok
+
+int main() {
+  test_no_return_constructor();
+}
+}