[clang][bytecode] Create a temporary for discarded CXXBindTemporaryExprs (#147303)

So we run the destructor.

Author: tbaederr

clang/lib/AST/ByteCode/Compiler.cpp

@@ -2886,7 +2886,20 @@ bool Compiler<Emitter>::VisitMaterializeTemporaryExpr(
 template <class Emitter>
 bool Compiler<Emitter>::VisitCXXBindTemporaryExpr(
     const CXXBindTemporaryExpr *E) {
-  return this->delegate(E->getSubExpr());
+  const Expr *SubExpr = E->getSubExpr();
+
+  if (Initializing)
+    return this->delegate(SubExpr);
+
+  // Make sure we create a temporary even if we're discarding, since that will
+  // make sure we will also call the destructor.
+
+  if (!this->visit(SubExpr))
+    return false;
+
+  if (DiscardResult)
+    return this->emitPopPtr(E);
+  return true;
 }
 
 template <class Emitter>

clang/lib/AST/ByteCode/Context.cpp

@@ -67,7 +67,8 @@ bool Context::evaluateAsRValue(State &Parent, const Expr *E, APValue &Result) {
   }
 
   if (!Recursing) {
-    assert(Stk.empty());
+    // We *can* actually get here with a non-empty stack, since
+    // things like InterpState::noteSideEffect() exist.
     C.cleanup();
 #ifndef NDEBUG
     // Make sure we don't rely on some value being still alive in

clang/test/SemaCXX/cxx2a-constexpr-dynalloc.cpp

@@ -3,6 +3,11 @@
 // RUN: %clang_cc1 -std=c++2a -verify=expected,cxx20 %s "-DNEW=::operator new" "-DDELETE=::operator delete"
 // RUN: %clang_cc1 -std=c++2c -verify=expected,cxx26 %s "-DNEW=::operator new" "-DDELETE=::operator delete"
 
+// RUN: %clang_cc1 -std=c++2a -verify=expected,cxx20 %s -DNEW=__builtin_operator_new -DDELETE=__builtin_operator_delete
+// RUN: %clang_cc1 -std=c++2a -verify=expected,cxx20 %s "-DNEW=operator new" "-DDELETE=operator delete"
+// RUN: %clang_cc1 -std=c++2a -verify=expected,cxx20 %s "-DNEW=::operator new" "-DDELETE=::operator delete"
+// RUN: %clang_cc1 -std=c++2c -verify=expected,cxx26 %s "-DNEW=::operator new" "-DDELETE=::operator delete"
+
 constexpr bool alloc_from_user_code() {
   void *p = NEW(sizeof(int)); // expected-note {{cannot allocate untyped memory in a constant expression; use 'std::allocator<T>::allocate'}}
   DELETE(p);