From be3e4875d65309e391c8016b3d340700e8c2e457 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Timm=20B=C3=A4der?= <tbaeder@redhat.com>
Date: Fri, 24 Oct 2025 17:27:10 +0200
Subject: [PATCH] [clang][bytecode] Handle discarded AddrLabelExprs properly

emitDummyPtr() doesn't like to be called with DiscardResult set, so
check this first.

Fixes https://github.com/llvm/llvm-project/issues/164979
---
 clang/lib/AST/ByteCode/Compiler.cpp | 2 ++
 clang/test/AST/ByteCode/cxx11.cpp   | 9 +++++++++
 2 files changed, 11 insertions(+)

diff --git a/clang/lib/AST/ByteCode/Compiler.cpp b/clang/lib/AST/ByteCode/Compiler.cpp
index 836d22f6e5389..9d73c1ecfacdd 100644
--- a/clang/lib/AST/ByteCode/Compiler.cpp
+++ b/clang/lib/AST/ByteCode/Compiler.cpp
@@ -3942,6 +3942,8 @@ bool Compiler<Emitter>::VisitRecoveryExpr(const RecoveryExpr *E) {
 template <class Emitter>
 bool Compiler<Emitter>::VisitAddrLabelExpr(const AddrLabelExpr *E) {
   assert(E->getType()->isVoidPointerType());
+  if (DiscardResult)
+    return true;
 
   return this->emitDummyPtr(E, E);
 }
diff --git a/clang/test/AST/ByteCode/cxx11.cpp b/clang/test/AST/ByteCode/cxx11.cpp
index 8efd3201d6200..427d3a106656b 100644
--- a/clang/test/AST/ByteCode/cxx11.cpp
+++ b/clang/test/AST/ByteCode/cxx11.cpp
@@ -370,3 +370,12 @@ namespace GH150709 {
   static_assert((e2[0].*mp)() == 1, ""); // ref-error {{constant expression}}
   static_assert((g.*mp)() == 1, ""); // ref-error {{constant expression}}
 }
+
+namespace DiscardedAddrLabel {
+  void foo(void) {
+  L:
+    *&&L; // both-error {{indirection not permitted}} \
+          // both-warning {{expression result unused}}
+  }
+}
+