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[Clang][CodeGen] Mark __dynamic_cast as willreturn #80409

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Merged
merged 1 commit into from
Feb 4, 2024
Merged

[Clang][CodeGen] Mark __dynamic_cast as willreturn #80409

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3 changes: 2 additions & 1 deletion clang/lib/CodeGen/ItaniumCXXABI.cpp
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Original file line number Diff line number Diff line change
Expand Up @@ -1347,9 +1347,10 @@ static llvm::FunctionCallee getItaniumDynamicCastFn(CodeGenFunction &CGF) {

llvm::FunctionType *FTy = llvm::FunctionType::get(Int8PtrTy, Args, false);

// Mark the function as nounwind readonly.
// Mark the function as nounwind willreturn readonly.
llvm::AttrBuilder FuncAttrs(CGF.getLLVMContext());
FuncAttrs.addAttribute(llvm::Attribute::NoUnwind);
FuncAttrs.addAttribute(llvm::Attribute::WillReturn);
FuncAttrs.addMemoryAttr(llvm::MemoryEffects::readOnly());
llvm::AttributeList Attrs = llvm::AttributeList::get(
CGF.getLLVMContext(), llvm::AttributeList::FunctionIndex, FuncAttrs);
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2 changes: 1 addition & 1 deletion clang/test/CodeGenCXX/dynamic-cast-address-space.cpp
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Expand Up @@ -20,5 +20,5 @@ const B& f(A *a) {

// CHECK: declare ptr @__dynamic_cast(ptr, ptr addrspace(1), ptr addrspace(1), i64) [[NUW_RO:#[0-9]+]]

// CHECK: attributes [[NUW_RO]] = { nounwind memory(read) }
// CHECK: attributes [[NUW_RO]] = { nounwind willreturn memory(read) }
// CHECK: attributes [[NR]] = { noreturn }
8 changes: 8 additions & 0 deletions clang/test/CodeGenCXX/dynamic-cast-dead.cpp
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@@ -0,0 +1,8 @@
// RUN: %clang_cc1 -I%S %s -O3 -triple x86_64-apple-darwin10 -emit-llvm -fcxx-exceptions -fexceptions -std=c++11 -o - | FileCheck %s
struct A { virtual ~A(); };
struct B : A { };

void foo(A* a) {
// CHECK-NOT: call {{.*}} @__dynamic_cast
B* b = dynamic_cast<B*>(a);
}
2 changes: 1 addition & 1 deletion clang/test/CodeGenCXX/dynamic-cast.cpp
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Expand Up @@ -20,5 +20,5 @@ const B& f(A *a) {

// CHECK: declare ptr @__dynamic_cast(ptr, ptr, ptr, i64) [[NUW_RO:#[0-9]+]]

// CHECK: attributes [[NUW_RO]] = { nounwind memory(read) }
// CHECK: attributes [[NUW_RO]] = { nounwind willreturn memory(read) }
// CHECK: attributes [[NR]] = { noreturn }