test/CodeGenCXX/homogeneous-aggregates.cpp - llvm-project/clang - Git at Google

 // RUN: %clang_cc1 -triple powerpc64le-unknown-linux-gnu -emit-llvm -o - %s | FileCheck %s --check-prefix=PPC
 // RUN: %clang_cc1 -mfloat-abi hard -triple armv7-unknown-linux-gnueabi -emit-llvm -o - %s | FileCheck %s --check-prefix=ARM32
 // RUN: %clang_cc1 -mfloat-abi hard -triple aarch64-unknown-linux-gnu -emit-llvm -o - %s | FileCheck %s --check-prefix=ARM64
 // RUN: %clang_cc1 -mfloat-abi hard -triple x86_64-unknown-windows-gnu -emit-llvm -o - %s | FileCheck %s --check-prefix=X64
 // RUN: %clang_cc1 -mfloat-abi hard -triple aarch64-unknown-windows-msvc -emit-llvm -o - %s | FileCheck %s --check-prefix=WOA64

 #if defined(__x86_64__)
 #define CC __attribute__((vectorcall))
 #else
 #define CC
 #endif

 // Test that C++ classes are correctly classified as homogeneous aggregates.

 struct Base1 {
   int x;
 };
 struct Base2 {
   double x;
 };
 struct Base3 {
   double x;
 };
 struct D1 : Base1 {  // non-homogeneous aggregate
   double y, z;
 };
 struct D2 : Base2 {  // homogeneous aggregate
   double y, z;
 };
 struct D3 : Base1, Base2 {  // non-homogeneous aggregate
   double y, z;
 };
 struct D4 : Base2, Base3 {  // homogeneous aggregate
   double y, z;
 };

 struct I1 : Base2 {};
 struct I2 : Base2 {};
 struct I3 : Base2 {};
 struct D5 : I1, I2, I3 {}; // homogeneous aggregate

 // PPC: define{{.*}} void @_Z7func_D12D1(ptr dead_on_unwind noalias writable sret(%struct.D1) align 8 %agg.result, [3 x i64] %x.coerce)
 // ARM32: define{{.*}} arm_aapcs_vfpcc void @_Z7func_D12D1(ptr dead_on_unwind noalias writable sret(%struct.D1) align 8 %agg.result, [3 x i64] %x.coerce)
 // ARM64: define{{.*}} void @_Z7func_D12D1(ptr dead_on_unwind noalias writable sret(%struct.D1) align 8 %agg.result, ptr noundef %x)
 // X64: define dso_local x86_vectorcallcc void @"\01_Z7func_D12D1@@24"(ptr dead_on_unwind noalias writable sret(%struct.D1) align 8 %agg.result, ptr noundef %x)
 D1 CC func_D1(D1 x) { return x; }

 // PPC: define{{.*}} [3 x double] @_Z7func_D22D2([3 x double] %x.coerce)
 // ARM32: define{{.*}} arm_aapcs_vfpcc %struct.D2 @_Z7func_D22D2(%struct.D2 %x.coerce)
 // ARM64: define{{.*}} %struct.D2 @_Z7func_D22D2([3 x double] alignstack(8) %x.coerce)
 // X64: define dso_local x86_vectorcallcc %struct.D2 @"\01_Z7func_D22D2@@24"(%struct.D2 inreg %x.coerce)
 D2 CC func_D2(D2 x) { return x; }

 // PPC: define{{.*}} void @_Z7func_D32D3(ptr dead_on_unwind noalias writable sret(%struct.D3) align 8 %agg.result, [4 x i64] %x.coerce)
 // ARM32: define{{.*}} arm_aapcs_vfpcc void @_Z7func_D32D3(ptr dead_on_unwind noalias writable sret(%struct.D3) align 8 %agg.result, [4 x i64] %x.coerce)
 // ARM64: define{{.*}} void @_Z7func_D32D3(ptr dead_on_unwind noalias writable sret(%struct.D3) align 8 %agg.result, ptr noundef %x)
 D3 CC func_D3(D3 x) { return x; }

 // PPC: define{{.*}} [4 x double] @_Z7func_D42D4([4 x double] %x.coerce)
 // ARM32: define{{.*}} arm_aapcs_vfpcc %struct.D4 @_Z7func_D42D4(%struct.D4 %x.coerce)
 // ARM64: define{{.*}} %struct.D4 @_Z7func_D42D4([4 x double] alignstack(8) %x.coerce)
 D4 CC func_D4(D4 x) { return x; }

 D5 CC func_D5(D5 x) { return x; }
 // PPC: define{{.*}} [3 x double] @_Z7func_D52D5([3 x double] %x.coerce)
 // ARM32: define{{.*}} arm_aapcs_vfpcc %struct.D5 @_Z7func_D52D5(%struct.D5 %x.coerce)

 // The C++ multiple inheritance expansion case is a little more complicated, so
 // do some extra checking.
 //
 // ARM64-LABEL: define{{.*}} %struct.D5 @_Z7func_D52D5([3 x double] alignstack(8) %x.coerce)
 // ARM64: store [3 x double] %x.coerce, ptr

 void call_D5(D5 *p) {
   func_D5(*p);
 }

 // Check the call site.
 //
 // ARM64-LABEL: define{{.*}} void @_Z7call_D5P2D5(ptr noundef %p)
 // ARM64: load [3 x double], ptr
 // ARM64: call %struct.D5 @_Z7func_D52D5([3 x double] alignstack(8) %{{.*}})

 struct Empty { };
 struct Float1 { float x; };
 struct Float2 { float y; };
 struct HVAWithEmptyBase : Float1, Empty, Float2 { float z; };

 // PPC: define{{.*}} void @_Z15with_empty_base16HVAWithEmptyBase([3 x float] %a.coerce)
 // ARM64: define{{.*}} void @_Z15with_empty_base16HVAWithEmptyBase([3 x float] alignstack(8) %a.coerce)
 // ARM32: define{{.*}} arm_aapcs_vfpcc void @_Z15with_empty_base16HVAWithEmptyBase(%struct.HVAWithEmptyBase %a.coerce)
 void CC with_empty_base(HVAWithEmptyBase a) {}

 // WOA64: define dso_local void @"?with_empty_base@@YAXUHVAWithEmptyBase@@@Z"([2 x i64] %{{.*}})
 // X64: define dso_local x86_vectorcallcc void @"\01_Z15with_empty_base16HVAWithEmptyBase@@16"(%struct.HVAWithEmptyBase inreg %a.coerce)

 struct HVAWithEmptyBitField : Float1, Float2 {
   int : 0; // Takes no space.
   float z;
 };

 // PPC: define{{.*}} void @_Z19with_empty_bitfield20HVAWithEmptyBitField([3 x float] %a.coerce)
 // ARM64: define{{.*}} void @_Z19with_empty_bitfield20HVAWithEmptyBitField([3 x float] alignstack(8) %a.coerce)
 // ARM32: define{{.*}} arm_aapcs_vfpcc void @_Z19with_empty_bitfield20HVAWithEmptyBitField(%struct.HVAWithEmptyBitField %a.coerce)
 // X64: define dso_local x86_vectorcallcc void @"\01_Z19with_empty_bitfield20HVAWithEmptyBitField@@16"(%struct.HVAWithEmptyBitField inreg %a.coerce)
 void CC with_empty_bitfield(HVAWithEmptyBitField a) {}

 namespace pr47611 {
 // MSVC on Arm includes "isCXX14Aggregate" as part of its definition of
 // Homogeneous Floating-point Aggregate (HFA). Additionally, it has a different
 // handling of C++14 aggregates, which can lead to confusion.

 // Pod is a trivial HFA.
 struct Pod {
   double b[2];
 };
 // Not an aggregate according to C++14 spec => not HFA according to MSVC.
 struct NotCXX14Aggregate {
   NotCXX14Aggregate();
   Pod p;
 };
 // NotPod is a C++14 aggregate. But not HFA, because it contains
 // NotCXX14Aggregate (which itself is not HFA because it's not a C++14
 // aggregate).
 struct NotPod {
   NotCXX14Aggregate x;
 };
 struct Empty {};
 // A class with a base is returned using the sret calling convetion by MSVC.
 struct HasEmptyBase : public Empty {
   double b[2];
 };
 struct HasPodBase : public Pod {};
 // WOA64-LABEL: define dso_local %"struct.pr47611::Pod" @"?copy@pr47611@@YA?AUPod@1@PEAU21@@Z"(ptr noundef %x)
 Pod copy(Pod *x) { return *x; } // MSVC: ldp d0,d1,[x0], Clang: ldp d0,d1,[x0]
 // WOA64-LABEL: define dso_local void @"?copy@pr47611@@YA?AUNotCXX14Aggregate@1@PEAU21@@Z"(ptr dead_on_unwind inreg noalias writable sret(%"struct.pr47611::NotCXX14Aggregate") align 8 %agg.result, ptr noundef %x)
 NotCXX14Aggregate copy(NotCXX14Aggregate *x) { return *x; } // MSVC: stp x8,x9,[x0], Clang: str q0,[x0]
 // WOA64-LABEL: define dso_local [2 x i64] @"?copy@pr47611@@YA?AUNotPod@1@PEAU21@@Z"(ptr noundef %x)
 NotPod copy(NotPod *x) { return *x; }
 // WOA64-LABEL: define dso_local void @"?copy@pr47611@@YA?AUHasEmptyBase@1@PEAU21@@Z"(ptr dead_on_unwind inreg noalias writable sret(%"struct.pr47611::HasEmptyBase") align 8 %agg.result, ptr noundef %x)
 HasEmptyBase copy(HasEmptyBase *x) { return *x; }
 // WOA64-LABEL: define dso_local void @"?copy@pr47611@@YA?AUHasPodBase@1@PEAU21@@Z"(ptr dead_on_unwind inreg noalias writable sret(%"struct.pr47611::HasPodBase") align 8 %agg.result, ptr noundef %x)
 HasPodBase copy(HasPodBase *x) { return *x; }

 void call_copy_pod(Pod *pod) {
   *pod = copy(pod);
   // WOA64-LABEL: define dso_local void @"?call_copy_pod@pr47611@@YAXPEAUPod@1@@Z"
   // WOA64: %{{.*}} = call %"struct.pr47611::Pod" @"?copy@pr47611@@YA?AUPod@1@PEAU21@@Z"(ptr noundef %{{.*}})
 }

 void call_copy_notcxx14aggregate(NotCXX14Aggregate *notcxx14aggregate) {
   *notcxx14aggregate = copy(notcxx14aggregate);
   // WOA64-LABEL: define dso_local void @"?call_copy_notcxx14aggregate@pr47611@@YAXPEAUNotCXX14Aggregate@1@@Z"
   // WOA64: call void @"?copy@pr47611@@YA?AUNotCXX14Aggregate@1@PEAU21@@Z"(ptr dead_on_unwind inreg writable sret(%"struct.pr47611::NotCXX14Aggregate") align 8 %{{.*}}, ptr noundef %{{.*}})
 }

 void call_copy_notpod(NotPod *notPod) {
   *notPod = copy(notPod);
   // WOA64-LABEL: define dso_local void @"?call_copy_notpod@pr47611@@YAXPEAUNotPod@1@@Z"
   // WOA64: %{{.*}} = call [2 x i64] @"?copy@pr47611@@YA?AUNotPod@1@PEAU21@@Z"(ptr noundef %{{.*}})
 }

 void call_copy_hasemptybase(HasEmptyBase *hasEmptyBase) {
   *hasEmptyBase = copy(hasEmptyBase);
   // WOA64-LABEL: define dso_local void @"?call_copy_hasemptybase@pr47611@@YAXPEAUHasEmptyBase@1@@Z"
   // WOA64: call void @"?copy@pr47611@@YA?AUHasEmptyBase@1@PEAU21@@Z"(ptr dead_on_unwind inreg writable sret(%"struct.pr47611::HasEmptyBase") align 8 %{{.*}}, ptr noundef %{{.*}})
 }

 void call_copy_haspodbase(HasPodBase *hasPodBase) {
   *hasPodBase = copy(hasPodBase);
   // WOA64-LABEL: define dso_local void @"?call_copy_haspodbase@pr47611@@YAXPEAUHasPodBase@1@@Z"
   // WOA64: call void @"?copy@pr47611@@YA?AUHasPodBase@1@PEAU21@@Z"(ptr dead_on_unwind inreg writable sret(%"struct.pr47611::HasPodBase") align 8 %{{.*}}, ptr noundef %{{.*}})
 }
 } // namespace pr47611

 namespace protected_member {
 struct HFA {
   double x;
   double y;
 protected:
   double z;
 };
 double foo(HFA v) { return v.x + v.y; }
 // WOA64: define dso_local noundef double @"?foo@protected_member@@YANUHFA@1@@Z"([3 x double] %{{.*}})
 }
 namespace private_member {
 struct HFA {
   double x;
   double y;
 private:
   double z;
 };
 double foo(HFA v) { return v.x + v.y; }
 // WOA64: define dso_local noundef double @"?foo@private_member@@YANUHFA@1@@Z"([3 x double] %{{.*}})
 }
 namespace polymorphic {
 struct NonHFA {
   double x;
   double y;
   double z;
   virtual void f1();
 };
 double foo(NonHFA v) { return v.x + v.y; }
 // WOA64: define dso_local noundef double @"?foo@polymorphic@@YANUNonHFA@1@@Z"(ptr noundef %{{.*}})
 }
 namespace trivial_copy_assignment {
 struct HFA {
   double x;
   double y;
   double z;
   HFA &operator=(const HFA&) = default;
 };
 double foo(HFA v) { return v.x + v.y; }
 // WOA64: define dso_local noundef double @"?foo@trivial_copy_assignment@@YANUHFA@1@@Z"([3 x double] %{{.*}})
 }
 namespace non_trivial_copy_assignment {
 struct NonHFA {
   double x;
   double y;
   double z;
   NonHFA &operator=(const NonHFA&);
 };
 double foo(NonHFA v) { return v.x + v.y; }
 // WOA64: define dso_local noundef double @"?foo@non_trivial_copy_assignment@@YANUNonHFA@1@@Z"(ptr noundef %{{.*}})
 }
 namespace user_provided_ctor {
 struct HFA {
   double x;
   double y;
   double z;
   HFA(int);
 };
 double foo(HFA v) { return v.x + v.y; }
 // WOA64: define dso_local noundef double @"?foo@user_provided_ctor@@YANUHFA@1@@Z"([3 x double] %{{.*}})
 }
 namespace trivial_dtor {
 struct HFA {
   double x;
   double y;
   double z;
   ~HFA() = default;
 };
 double foo(HFA v) { return v.x + v.y; }
 // WOA64: define dso_local noundef double @"?foo@trivial_dtor@@YANUHFA@1@@Z"([3 x double] %{{.*}})
 }
 namespace non_trivial_dtor {
 struct NonHFA {
   double x;
   double y;
   double z;
   ~NonHFA();
 };
 double foo(NonHFA v) { return v.x + v.y; }
 // WOA64: define dso_local noundef double @"?foo@non_trivial_dtor@@YANUNonHFA@1@@Z"(ptr noundef %{{.*}})
 }
 namespace non_empty_base {
 struct non_empty_base { double d; };
 struct HFA : non_empty_base {
   double x;
   double y;
   double z;
 };
 double foo(HFA v) { return v.x + v.y; }
 // WOA64: define dso_local noundef double @"?foo@non_empty_base@@YANUHFA@1@@Z"([4 x double] %{{.*}})
 }
 namespace empty_field {
 struct empty { };
 struct NonHFA {
   double x;
   double y;
   double z;
   empty e;
 };
 double foo(NonHFA v) { return v.x + v.y; }
 // WOA64: define dso_local noundef double @"?foo@empty_field@@YANUNonHFA@1@@Z"(ptr noundef %{{.*}})
 }
 namespace non_empty_field {
 struct non_empty { double d; };
 struct HFA {
   double x;
   double y;
   double z;
   non_empty e;
 };
 double foo(HFA v) { return v.x + v.y; }
 // WOA64: define dso_local noundef double @"?foo@non_empty_field@@YANUHFA@1@@Z"([4 x double] %{{.*}})
 }

 namespace pr62223 {
 // HVAs don't follow the normal rules for return values. That means they can
 // have base classes, user-defined ctors, and protected/private members.
 // (The same restrictions that apply to HVA arguments still apply.)
 typedef double V __attribute((ext_vector_type(2)));
 struct base { V v; };
 struct test : base { test(double); protected: V v2;};
 test f(test *x) { return *x; }
 // WOA64: define dso_local %"struct.pr62223::test" @"?f@pr62223@@YA?AUtest@1@PEAU21@@Z"(ptr noundef %{{.*}})

 // The above rule only apples to HVAs, not HFAs.
 struct base2 { double v; };
 struct test2 : base2 { test2(double); protected: double v2;};
 test2 f(test2 *x) { return *x; }
 // WOA64: define dso_local void @"?f@pr62223@@YA?AUtest2@1@PEAU21@@Z"(ptr dead_on_unwind inreg noalias writable sret(%"struct.pr62223::test2") align 8 %{{.*}}, ptr noundef %{{.*}})
 }
	// RUN: %clang_cc1 -triple powerpc64le-unknown-linux-gnu -emit-llvm -o - %s \| FileCheck %s --check-prefix=PPC
	// RUN: %clang_cc1 -mfloat-abi hard -triple armv7-unknown-linux-gnueabi -emit-llvm -o - %s \| FileCheck %s --check-prefix=ARM32
	// RUN: %clang_cc1 -mfloat-abi hard -triple aarch64-unknown-linux-gnu -emit-llvm -o - %s \| FileCheck %s --check-prefix=ARM64
	// RUN: %clang_cc1 -mfloat-abi hard -triple x86_64-unknown-windows-gnu -emit-llvm -o - %s \| FileCheck %s --check-prefix=X64
	// RUN: %clang_cc1 -mfloat-abi hard -triple aarch64-unknown-windows-msvc -emit-llvm -o - %s \| FileCheck %s --check-prefix=WOA64

	#if defined(__x86_64__)
	#define CC __attribute__((vectorcall))
	#else
	#define CC
	#endif

	// Test that C++ classes are correctly classified as homogeneous aggregates.

	struct Base1 {
	int x;
	};
	struct Base2 {
	double x;
	};
	struct Base3 {
	double x;
	};
	struct D1 : Base1 { // non-homogeneous aggregate
	double y, z;
	};
	struct D2 : Base2 { // homogeneous aggregate
	double y, z;
	};
	struct D3 : Base1, Base2 { // non-homogeneous aggregate
	double y, z;
	};
	struct D4 : Base2, Base3 { // homogeneous aggregate
	double y, z;
	};

	struct I1 : Base2 {};
	struct I2 : Base2 {};
	struct I3 : Base2 {};
	struct D5 : I1, I2, I3 {}; // homogeneous aggregate

	// PPC: define{{.*}} void @_Z7func_D12D1(ptr dead_on_unwind noalias writable sret(%struct.D1) align 8 %agg.result, [3 x i64] %x.coerce)
	// ARM32: define{{.*}} arm_aapcs_vfpcc void @_Z7func_D12D1(ptr dead_on_unwind noalias writable sret(%struct.D1) align 8 %agg.result, [3 x i64] %x.coerce)
	// ARM64: define{{.*}} void @_Z7func_D12D1(ptr dead_on_unwind noalias writable sret(%struct.D1) align 8 %agg.result, ptr noundef %x)
	// X64: define dso_local x86_vectorcallcc void @"\01_Z7func_D12D1@@24"(ptr dead_on_unwind noalias writable sret(%struct.D1) align 8 %agg.result, ptr noundef %x)
	D1 CC func_D1(D1 x) { return x; }

	// PPC: define{{.*}} [3 x double] @_Z7func_D22D2([3 x double] %x.coerce)
	// ARM32: define{{.*}} arm_aapcs_vfpcc %struct.D2 @_Z7func_D22D2(%struct.D2 %x.coerce)
	// ARM64: define{{.*}} %struct.D2 @_Z7func_D22D2([3 x double] alignstack(8) %x.coerce)
	// X64: define dso_local x86_vectorcallcc %struct.D2 @"\01_Z7func_D22D2@@24"(%struct.D2 inreg %x.coerce)
	D2 CC func_D2(D2 x) { return x; }

	// PPC: define{{.*}} void @_Z7func_D32D3(ptr dead_on_unwind noalias writable sret(%struct.D3) align 8 %agg.result, [4 x i64] %x.coerce)
	// ARM32: define{{.*}} arm_aapcs_vfpcc void @_Z7func_D32D3(ptr dead_on_unwind noalias writable sret(%struct.D3) align 8 %agg.result, [4 x i64] %x.coerce)
	// ARM64: define{{.*}} void @_Z7func_D32D3(ptr dead_on_unwind noalias writable sret(%struct.D3) align 8 %agg.result, ptr noundef %x)
	D3 CC func_D3(D3 x) { return x; }

	// PPC: define{{.*}} [4 x double] @_Z7func_D42D4([4 x double] %x.coerce)
	// ARM32: define{{.*}} arm_aapcs_vfpcc %struct.D4 @_Z7func_D42D4(%struct.D4 %x.coerce)
	// ARM64: define{{.*}} %struct.D4 @_Z7func_D42D4([4 x double] alignstack(8) %x.coerce)
	D4 CC func_D4(D4 x) { return x; }

	D5 CC func_D5(D5 x) { return x; }
	// PPC: define{{.*}} [3 x double] @_Z7func_D52D5([3 x double] %x.coerce)
	// ARM32: define{{.*}} arm_aapcs_vfpcc %struct.D5 @_Z7func_D52D5(%struct.D5 %x.coerce)

	// The C++ multiple inheritance expansion case is a little more complicated, so
	// do some extra checking.
	//
	// ARM64-LABEL: define{{.*}} %struct.D5 @_Z7func_D52D5([3 x double] alignstack(8) %x.coerce)
	// ARM64: store [3 x double] %x.coerce, ptr

	void call_D5(D5 *p) {
	func_D5(*p);
	}

	// Check the call site.
	//
	// ARM64-LABEL: define{{.*}} void @_Z7call_D5P2D5(ptr noundef %p)
	// ARM64: load [3 x double], ptr
	// ARM64: call %struct.D5 @_Z7func_D52D5([3 x double] alignstack(8) %{{.*}})

	struct Empty { };
	struct Float1 { float x; };
	struct Float2 { float y; };
	struct HVAWithEmptyBase : Float1, Empty, Float2 { float z; };

	// PPC: define{{.*}} void @_Z15with_empty_base16HVAWithEmptyBase([3 x float] %a.coerce)
	// ARM64: define{{.*}} void @_Z15with_empty_base16HVAWithEmptyBase([3 x float] alignstack(8) %a.coerce)
	// ARM32: define{{.*}} arm_aapcs_vfpcc void @_Z15with_empty_base16HVAWithEmptyBase(%struct.HVAWithEmptyBase %a.coerce)
	void CC with_empty_base(HVAWithEmptyBase a) {}

	// WOA64: define dso_local void @"?with_empty_base@@YAXUHVAWithEmptyBase@@@Z"([2 x i64] %{{.*}})
	// X64: define dso_local x86_vectorcallcc void @"\01_Z15with_empty_base16HVAWithEmptyBase@@16"(%struct.HVAWithEmptyBase inreg %a.coerce)

	struct HVAWithEmptyBitField : Float1, Float2 {
	int : 0; // Takes no space.
	float z;
	};

	// PPC: define{{.*}} void @_Z19with_empty_bitfield20HVAWithEmptyBitField([3 x float] %a.coerce)
	// ARM64: define{{.*}} void @_Z19with_empty_bitfield20HVAWithEmptyBitField([3 x float] alignstack(8) %a.coerce)
	// ARM32: define{{.*}} arm_aapcs_vfpcc void @_Z19with_empty_bitfield20HVAWithEmptyBitField(%struct.HVAWithEmptyBitField %a.coerce)
	// X64: define dso_local x86_vectorcallcc void @"\01_Z19with_empty_bitfield20HVAWithEmptyBitField@@16"(%struct.HVAWithEmptyBitField inreg %a.coerce)
	void CC with_empty_bitfield(HVAWithEmptyBitField a) {}

	namespace pr47611 {
	// MSVC on Arm includes "isCXX14Aggregate" as part of its definition of
	// Homogeneous Floating-point Aggregate (HFA). Additionally, it has a different
	// handling of C++14 aggregates, which can lead to confusion.

	// Pod is a trivial HFA.
	struct Pod {
	double b[2];
	};
	// Not an aggregate according to C++14 spec => not HFA according to MSVC.
	struct NotCXX14Aggregate {
	NotCXX14Aggregate();
	Pod p;
	};
	// NotPod is a C++14 aggregate. But not HFA, because it contains
	// NotCXX14Aggregate (which itself is not HFA because it's not a C++14
	// aggregate).
	struct NotPod {
	NotCXX14Aggregate x;
	};
	struct Empty {};
	// A class with a base is returned using the sret calling convetion by MSVC.
	struct HasEmptyBase : public Empty {
	double b[2];
	};
	struct HasPodBase : public Pod {};
	// WOA64-LABEL: define dso_local %"struct.pr47611::Pod" @"?copy@pr47611@@YA?AUPod@1@PEAU21@@Z"(ptr noundef %x)
	Pod copy(Pod x) { return x; } // MSVC: ldp d0,d1,[x0], Clang: ldp d0,d1,[x0]
	// WOA64-LABEL: define dso_local void @"?copy@pr47611@@YA?AUNotCXX14Aggregate@1@PEAU21@@Z"(ptr dead_on_unwind inreg noalias writable sret(%"struct.pr47611::NotCXX14Aggregate") align 8 %agg.result, ptr noundef %x)
	NotCXX14Aggregate copy(NotCXX14Aggregate x) { return x; } // MSVC: stp x8,x9,[x0], Clang: str q0,[x0]
	// WOA64-LABEL: define dso_local [2 x i64] @"?copy@pr47611@@YA?AUNotPod@1@PEAU21@@Z"(ptr noundef %x)
	NotPod copy(NotPod x) { return x; }
	// WOA64-LABEL: define dso_local void @"?copy@pr47611@@YA?AUHasEmptyBase@1@PEAU21@@Z"(ptr dead_on_unwind inreg noalias writable sret(%"struct.pr47611::HasEmptyBase") align 8 %agg.result, ptr noundef %x)
	HasEmptyBase copy(HasEmptyBase x) { return x; }
	// WOA64-LABEL: define dso_local void @"?copy@pr47611@@YA?AUHasPodBase@1@PEAU21@@Z"(ptr dead_on_unwind inreg noalias writable sret(%"struct.pr47611::HasPodBase") align 8 %agg.result, ptr noundef %x)
	HasPodBase copy(HasPodBase x) { return x; }

	void call_copy_pod(Pod *pod) {
	*pod = copy(pod);
	// WOA64-LABEL: define dso_local void @"?call_copy_pod@pr47611@@YAXPEAUPod@1@@Z"
	// WOA64: %{{.}} = call %"struct.pr47611::Pod" @"?copy@pr47611@@YA?AUPod@1@PEAU21@@Z"(ptr noundef %{{.}})
	}

	void call_copy_notcxx14aggregate(NotCXX14Aggregate *notcxx14aggregate) {
	*notcxx14aggregate = copy(notcxx14aggregate);
	// WOA64-LABEL: define dso_local void @"?call_copy_notcxx14aggregate@pr47611@@YAXPEAUNotCXX14Aggregate@1@@Z"
	// WOA64: call void @"?copy@pr47611@@YA?AUNotCXX14Aggregate@1@PEAU21@@Z"(ptr dead_on_unwind inreg writable sret(%"struct.pr47611::NotCXX14Aggregate") align 8 %{{.}}, ptr noundef %{{.}})
	}

	void call_copy_notpod(NotPod *notPod) {
	*notPod = copy(notPod);
	// WOA64-LABEL: define dso_local void @"?call_copy_notpod@pr47611@@YAXPEAUNotPod@1@@Z"
	// WOA64: %{{.}} = call [2 x i64] @"?copy@pr47611@@YA?AUNotPod@1@PEAU21@@Z"(ptr noundef %{{.}})
	}

	void call_copy_hasemptybase(HasEmptyBase *hasEmptyBase) {
	*hasEmptyBase = copy(hasEmptyBase);
	// WOA64-LABEL: define dso_local void @"?call_copy_hasemptybase@pr47611@@YAXPEAUHasEmptyBase@1@@Z"
	// WOA64: call void @"?copy@pr47611@@YA?AUHasEmptyBase@1@PEAU21@@Z"(ptr dead_on_unwind inreg writable sret(%"struct.pr47611::HasEmptyBase") align 8 %{{.}}, ptr noundef %{{.}})
	}

	void call_copy_haspodbase(HasPodBase *hasPodBase) {
	*hasPodBase = copy(hasPodBase);
	// WOA64-LABEL: define dso_local void @"?call_copy_haspodbase@pr47611@@YAXPEAUHasPodBase@1@@Z"
	// WOA64: call void @"?copy@pr47611@@YA?AUHasPodBase@1@PEAU21@@Z"(ptr dead_on_unwind inreg writable sret(%"struct.pr47611::HasPodBase") align 8 %{{.}}, ptr noundef %{{.}})
	}
	} // namespace pr47611

	namespace protected_member {
	struct HFA {
	double x;
	double y;
	protected:
	double z;
	};
	double foo(HFA v) { return v.x + v.y; }
	// WOA64: define dso_local noundef double @"?foo@protected_member@@YANUHFA@1@@Z"([3 x double] %{{.*}})
	}
	namespace private_member {
	struct HFA {
	double x;
	double y;
	private:
	double z;
	};
	double foo(HFA v) { return v.x + v.y; }
	// WOA64: define dso_local noundef double @"?foo@private_member@@YANUHFA@1@@Z"([3 x double] %{{.*}})
	}
	namespace polymorphic {
	struct NonHFA {
	double x;
	double y;
	double z;
	virtual void f1();
	};
	double foo(NonHFA v) { return v.x + v.y; }
	// WOA64: define dso_local noundef double @"?foo@polymorphic@@YANUNonHFA@1@@Z"(ptr noundef %{{.*}})
	}
	namespace trivial_copy_assignment {
	struct HFA {
	double x;
	double y;
	double z;
	HFA &operator=(const HFA&) = default;
	};
	double foo(HFA v) { return v.x + v.y; }
	// WOA64: define dso_local noundef double @"?foo@trivial_copy_assignment@@YANUHFA@1@@Z"([3 x double] %{{.*}})
	}
	namespace non_trivial_copy_assignment {
	struct NonHFA {
	double x;
	double y;
	double z;
	NonHFA &operator=(const NonHFA&);
	};
	double foo(NonHFA v) { return v.x + v.y; }
	// WOA64: define dso_local noundef double @"?foo@non_trivial_copy_assignment@@YANUNonHFA@1@@Z"(ptr noundef %{{.*}})
	}
	namespace user_provided_ctor {
	struct HFA {
	double x;
	double y;
	double z;
	HFA(int);
	};
	double foo(HFA v) { return v.x + v.y; }
	// WOA64: define dso_local noundef double @"?foo@user_provided_ctor@@YANUHFA@1@@Z"([3 x double] %{{.*}})
	}
	namespace trivial_dtor {
	struct HFA {
	double x;
	double y;
	double z;
	~HFA() = default;
	};
	double foo(HFA v) { return v.x + v.y; }
	// WOA64: define dso_local noundef double @"?foo@trivial_dtor@@YANUHFA@1@@Z"([3 x double] %{{.*}})
	}
	namespace non_trivial_dtor {
	struct NonHFA {
	double x;
	double y;
	double z;
	~NonHFA();
	};
	double foo(NonHFA v) { return v.x + v.y; }
	// WOA64: define dso_local noundef double @"?foo@non_trivial_dtor@@YANUNonHFA@1@@Z"(ptr noundef %{{.*}})
	}
	namespace non_empty_base {
	struct non_empty_base { double d; };
	struct HFA : non_empty_base {
	double x;
	double y;
	double z;
	};
	double foo(HFA v) { return v.x + v.y; }
	// WOA64: define dso_local noundef double @"?foo@non_empty_base@@YANUHFA@1@@Z"([4 x double] %{{.*}})
	}
	namespace empty_field {
	struct empty { };
	struct NonHFA {
	double x;
	double y;
	double z;
	empty e;
	};
	double foo(NonHFA v) { return v.x + v.y; }
	// WOA64: define dso_local noundef double @"?foo@empty_field@@YANUNonHFA@1@@Z"(ptr noundef %{{.*}})
	}
	namespace non_empty_field {
	struct non_empty { double d; };
	struct HFA {
	double x;
	double y;
	double z;
	non_empty e;
	};
	double foo(HFA v) { return v.x + v.y; }
	// WOA64: define dso_local noundef double @"?foo@non_empty_field@@YANUHFA@1@@Z"([4 x double] %{{.*}})
	}

	namespace pr62223 {
	// HVAs don't follow the normal rules for return values. That means they can
	// have base classes, user-defined ctors, and protected/private members.
	// (The same restrictions that apply to HVA arguments still apply.)
	typedef double V __attribute((ext_vector_type(2)));
	struct base { V v; };
	struct test : base { test(double); protected: V v2;};
	test f(test x) { return x; }
	// WOA64: define dso_local %"struct.pr62223::test" @"?f@pr62223@@YA?AUtest@1@PEAU21@@Z"(ptr noundef %{{.*}})

	// The above rule only apples to HVAs, not HFAs.
	struct base2 { double v; };
	struct test2 : base2 { test2(double); protected: double v2;};
	test2 f(test2 x) { return x; }
	// WOA64: define dso_local void @"?f@pr62223@@YA?AUtest2@1@PEAU21@@Z"(ptr dead_on_unwind inreg noalias writable sret(%"struct.pr62223::test2") align 8 %{{.}}, ptr noundef %{{.}})
	}