[clang][bytecode] Fix discarding CompoundLiteralExprs (#104909)

Author: tbaederr

clang/lib/AST/ByteCode/Compiler.cpp

@@ -2325,6 +2325,9 @@ bool Compiler<Emitter>::VisitCXXBindTemporaryExpr(
 template <class Emitter>
 bool Compiler<Emitter>::VisitCompoundLiteralExpr(const CompoundLiteralExpr *E) {
   const Expr *Init = E->getInitializer();
+  if (DiscardResult)
+    return this->discard(Init);
+
   if (Initializing) {
     // We already have a value, just initialize that.
     return this->visitInitializer(Init) && this->emitFinishInit(E);
@@ -2378,9 +2381,6 @@ bool Compiler<Emitter>::VisitCompoundLiteralExpr(const CompoundLiteralExpr *E) {
       if (!this->visitInitializer(Init) || !this->emitFinishInit(E))
         return false;
     }
-
-    if (DiscardResult)
-      return this->emitPopPtr(E);
     return true;
   }
 

clang/test/AST/ByteCode/c23.c

@@ -1,7 +1,7 @@
 // RUN: %clang_cc1 -std=c23 -fexperimental-new-constant-interpreter -verify=expected,both %s
 // RUN: %clang_cc1 -std=c23 -verify=ref,both %s
 
-
+typedef typeof(nullptr) nullptr_t;
 
 const _Bool inf1 =  (1.0/0.0 == __builtin_inf());
 constexpr _Bool inf2 = (1.0/0.0 == __builtin_inf()); // both-error {{must be initialized by a constant expression}} \
@@ -22,3 +22,6 @@ char bar() {
   ((struct S *)buffer)->c = 'a';
   return ((struct S *)buffer)->c;
 }
+
+
+static_assert((nullptr_t){} == 0);