[clang] [clang][bytecode] Always return false for invalid bcp results (PR #121467)

[Timm Baeder via cfe-commits]

https://github.com/tbaederr created https://github.com/llvm/llvm-project/pull/121467

None

>From 64b56760ef4d701f36204588ea82c0ecc24579f4 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Timm=20B=C3=A4der?= <tbaeder at redhat.com>
Date: Thu, 2 Jan 2025 12:08:17 +0100
Subject: [PATCH] [clang][bytecode] Always return false for invalid bcp results

---
 clang/lib/AST/ByteCode/InterpBuiltin.cpp       | 3 ++-
 clang/test/AST/ByteCode/builtin-constant-p.cpp | 6 ++++++
 2 files changed, 8 insertions(+), 1 deletion(-)

diff --git a/clang/lib/AST/ByteCode/InterpBuiltin.cpp b/clang/lib/AST/ByteCode/InterpBuiltin.cpp
index b5849553d0bf53..731c9290993f12 100644
--- a/clang/lib/AST/ByteCode/InterpBuiltin.cpp
+++ b/clang/lib/AST/ByteCode/InterpBuiltin.cpp
@@ -1544,9 +1544,10 @@ static bool interp__builtin_constant_p(InterpState &S, CodePtr OpPC,
     if (Res.isInvalid()) {
       C.cleanup();
       Stk.clear();
+      return returnInt(false);
     }
 
-    if (!Res.isInvalid() && !Res.empty()) {
+    if (!Res.empty()) {
       const APValue &LV = Res.toAPValue();
       if (LV.isLValue()) {
         APValue::LValueBase Base = LV.getLValueBase();
diff --git a/clang/test/AST/ByteCode/builtin-constant-p.cpp b/clang/test/AST/ByteCode/builtin-constant-p.cpp
index 0d222d1c962778..62899b60064c28 100644
--- a/clang/test/AST/ByteCode/builtin-constant-p.cpp
+++ b/clang/test/AST/ByteCode/builtin-constant-p.cpp
@@ -12,3 +12,9 @@ static_assert(__builtin_constant_p(I + 10.0), "");
 static_assert(__builtin_constant_p(nullptr), "");
 static_assert(__builtin_constant_p(&I), ""); // both-error {{failed due to requirement}}
 static_assert(__builtin_constant_p((void)I), ""); // both-error {{failed due to requirement}}
+
+extern int z;
+constexpr int foo(int &a) {
+  return __builtin_constant_p(a);
+}
+static_assert(!foo(z));