https://github.com/Nikunj-Pokharel updated https://github.com/llvm/llvm-project/pull/235011
>From 0cdbd5874830d9d966b8975ef29f64a695b7b06f Mon Sep 17 00:00:00 2001 From: Xen00n <[email protected]> Date: Fri, 23 Oct 2026 19:59:25 +0530 Subject: [PATCH 1/2] Fix zero initialization of virtual bases in delegating constructors --- clang/lib/CodeGen/CGExprCXX.cpp | 6 ++++++ clang/test/CodeGenCXX/issue-234795.cpp | 30 ++++++++++++++++++++++++++ 2 files changed, 36 insertions(+) create mode 100644 clang/test/CodeGenCXX/issue-234795.cpp diff --git a/clang/lib/CodeGen/CGExprCXX.cpp b/clang/lib/CodeGen/CGExprCXX.cpp index 60bb27a6fab69d..e41f5c24da1c79 100644 --- a/clang/lib/CodeGen/CGExprCXX.cpp +++ b/clang/lib/CodeGen/CGExprCXX.cpp @@ -633,6 +633,12 @@ void CodeGenFunction::EmitCXXConstructExpr(const CXXConstructExpr *E, if (E->requiresZeroInitialization() && !Dest.isZeroed()) { switch (E->getConstructionKind()) { case CXXConstructionKind::Delegating: + if (CurGD.getCtorType() == Ctor_Base) + EmitNullBaseClassInitialization(*this, Dest.getAddress(), + CD->getParent()); + else + EmitNullInitialization(Dest.getAddress(), E->getType()); + break; case CXXConstructionKind::Complete: EmitNullInitialization(Dest.getAddress(), E->getType()); break; diff --git a/clang/test/CodeGenCXX/issue-234795.cpp b/clang/test/CodeGenCXX/issue-234795.cpp new file mode 100644 index 00000000000000..c1ec6db6b54025 --- /dev/null +++ b/clang/test/CodeGenCXX/issue-234795.cpp @@ -0,0 +1,30 @@ +// RUN: %clang_cc1 -std=c++17 -O0 -emit-llvm -o - %s | FileCheck %s + +struct A { + int x = 42; + virtual ~A() {} +}; + +struct B : virtual A { + explicit B(int) : B() {} + B() = default; +}; + +struct D : B { + D() : B(0) {} +}; + +int main() { + D d; + B b(0); + return d.x + b.x; +} + +// The complete-object constructor initializes the full object. +// CHECK-LABEL: define{{.*}} @_ZN1BC1Ei +// CHECK: call void @llvm.memset{{.*}}i64 24 + +// The base-object constructor must not zero-initialize its virtual base. +// CHECK-LABEL: define{{.*}} @_ZN1BC2Ei +// CHECK: call void @llvm.memset{{.*}}i64 8 +// CHECK: call{{.*}} @_ZN1BC2Ev \ No newline at end of file >From 80ff5c6354ca91c8d19204faf0e9dce647ad5481 Mon Sep 17 00:00:00 2001 From: Xen00n <[email protected]> Date: Sat, 24 Oct 2026 11:10:57 +0530 Subject: [PATCH 2/2] Fix Windows compatibility of virtual base initialization test --- clang/test/CodeGenCXX/issue-234795.cpp | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/clang/test/CodeGenCXX/issue-234795.cpp b/clang/test/CodeGenCXX/issue-234795.cpp index c1ec6db6b54025..2c3a511c28e145 100644 --- a/clang/test/CodeGenCXX/issue-234795.cpp +++ b/clang/test/CodeGenCXX/issue-234795.cpp @@ -1,4 +1,4 @@ -// RUN: %clang_cc1 -std=c++17 -O0 -emit-llvm -o - %s | FileCheck %s +// RUN: %clang_cc1 -triple x86_64-unknown-linux-gnu -std=c++17 -O0 -emit-llvm -o - %s | FileCheck %s struct A { int x = 42; _______________________________________________ cfe-commits mailing list [email protected] https://lists.llvm.org/cgi-bin/mailman/listinfo/cfe-commits
