[clang] [clang][bytecode] Fix ImplicitValueInitExpr array initializer (PR #205754)

[Timm Baeder via cfe-commits]

https://github.com/tbaederr created https://github.com/llvm/llvm-project/pull/205754

... if the allocation is dynamic and the array is multidimensional.

>From dc97c1eda18c75cbb1b55e9bf1bd8ecd9fb4a57e Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Timm=20B=C3=A4der?= <tbaeder at redhat.com>
Date: Thu, 25 Jun 2026 11:11:01 +0200
Subject: [PATCH] [clang][bytecode] Fix ImplicitValueInitExpr array initializer

... if the allocation is dynamic and the array is multidimensional.
---
 clang/lib/AST/ByteCode/Compiler.cpp    | 15 ++++++++++-----
 clang/test/AST/ByteCode/new-delete.cpp | 11 +++++++++++
 2 files changed, 21 insertions(+), 5 deletions(-)

diff --git a/clang/lib/AST/ByteCode/Compiler.cpp b/clang/lib/AST/ByteCode/Compiler.cpp
index d2e28e516eaab..cadb040048384 100644
--- a/clang/lib/AST/ByteCode/Compiler.cpp
+++ b/clang/lib/AST/ByteCode/Compiler.cpp
@@ -4102,11 +4102,16 @@ bool Compiler<Emitter>::VisitCXXNewExpr(const CXXNewExpr *E) {
             DynamicInit->getType()->isArrayType()) {
           QualType ElemType =
               DynamicInit->getType()->getAsArrayTypeUnsafe()->getElementType();
-          PrimType InitT = classifyPrim(ElemType);
-          if (!this->visitZeroInitializer(InitT, ElemType, E))
-            return false;
-          if (!this->emitStorePop(InitT, E))
-            return false;
+          if (OptPrimType InitT = classify(ElemType)) {
+            if (!this->visitZeroInitializer(*InitT, ElemType, E))
+              return false;
+            if (!this->emitStorePop(*InitT, E))
+              return false;
+          } else {
+            assert(ElemType->isArrayType());
+            if (!this->visitZeroArrayInitializer(ElemType, E))
+              return false;
+          }
         } else if (DynamicInit) {
           if (OptPrimType InitT = classify(DynamicInit)) {
             if (!this->visit(DynamicInit))
diff --git a/clang/test/AST/ByteCode/new-delete.cpp b/clang/test/AST/ByteCode/new-delete.cpp
index 43d770d5c9e61..0e2db787ca48c 100644
--- a/clang/test/AST/ByteCode/new-delete.cpp
+++ b/clang/test/AST/ByteCode/new-delete.cpp
@@ -1267,6 +1267,17 @@ namespace FreeNonBlockPointer {
   static_assert(foo() == 10); // both-error {{not an integral constant expression}}
 }
 
+namespace NonPrimitiveImplicitValueInitExpr {
+  constexpr int m() {
+    int r;
+    auto foo = new int[2][4][1]{};
+    r = foo[0][2][0];
+    delete[] foo;
+    return r;
+  }
+  static_assert(m() == 0);
+}
+
 #else
 /// Make sure we reject this prior to C++20
 constexpr int a() { // both-error {{never produces a constant expression}}