1 files changed, 221 insertions, 0 deletions
diff --git a/tests/codegen-llvm/repr/transparent.rs b/tests/codegen-llvm/repr/transparent.rs
new file mode 100644
index 00000000000..29b627462a4
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+++ b/tests/codegen-llvm/repr/transparent.rs
@@ -0,0 +1,221 @@
+//@ compile-flags: -Copt-level=3 -C no-prepopulate-passes
+//@ ignore-riscv64 riscv64 has an i128 type used with test_Vector
+//@ ignore-s390x s390x with default march passes vector types per reference
+//@ ignore-loongarch64 see codegen/loongarch-abi for loongarch function call tests
+
+// This codegen test embeds assumptions about how certain "C" psABIs are handled
+// so it doesn't apply to all architectures or even all OS
+// For RISCV: see codegen/riscv-abi
+// For LoongArch: see codegen/loongarch-abi
+
+#![crate_type = "lib"]
+#![feature(repr_simd, transparent_unions, arm_target_feature, mips_target_feature)]
+
+use std::marker::PhantomData;
+
+#[derive(Copy, Clone)]
+pub struct Zst1;
+#[derive(Copy, Clone)]
+pub struct Zst2(());
+
+#[derive(Copy, Clone)]
+#[repr(transparent)]
+pub struct F32(f32);
+
+// CHECK: define{{.*}}float @test_F32(float noundef %_1)
+#[no_mangle]
+pub extern "C" fn test_F32(_: F32) -> F32 {
+    loop {}
+}
+
+#[repr(transparent)]
+pub struct Ptr(*mut u8);
+
+// CHECK: define{{.*}}ptr @test_Ptr(ptr noundef %_1)
+#[no_mangle]
+pub extern "C" fn test_Ptr(_: Ptr) -> Ptr {
+    loop {}
+}
+
+#[repr(transparent)]
+pub struct WithZst(u64, Zst1);
+
+// CHECK: define{{.*}}i64 @test_WithZst(i64 noundef %_1)
+#[no_mangle]
+pub extern "C" fn test_WithZst(_: WithZst) -> WithZst {
+    loop {}
+}
+
+#[repr(transparent)]
+pub struct WithZeroSizedArray(*const f32, [i8; 0]);
+
+// CHECK: define{{.*}}ptr @test_WithZeroSizedArray(ptr noundef %_1)
+#[no_mangle]
+pub extern "C" fn test_WithZeroSizedArray(_: WithZeroSizedArray) -> WithZeroSizedArray {
+    loop {}
+}
+
+#[repr(transparent)]
+pub struct Generic<T>(T);
+
+// CHECK: define{{.*}}double @test_Generic(double noundef %_1)
+#[no_mangle]
+pub extern "C" fn test_Generic(_: Generic<f64>) -> Generic<f64> {
+    loop {}
+}
+
+#[repr(transparent)]
+pub struct GenericPlusZst<T>(T, Zst2);
+
+#[repr(u8)]
+pub enum Bool {
+    True,
+    False,
+    FileNotFound,
+}
+
+// CHECK: define{{( dso_local)?}} noundef{{( zeroext)?( range\(i8 0, 3\))?}} i8 @test_Gpz(i8 noundef{{( zeroext)?( range\(i8 0, 3\))?}} %_1)
+#[no_mangle]
+pub extern "C" fn test_Gpz(_: GenericPlusZst<Bool>) -> GenericPlusZst<Bool> {
+    loop {}
+}
+
+#[repr(transparent)]
+pub struct LifetimePhantom<'a, T: 'a>(*const T, PhantomData<&'a T>);
+
+// CHECK: define{{.*}}ptr @test_LifetimePhantom(ptr noundef %_1)
+#[no_mangle]
+pub extern "C" fn test_LifetimePhantom(_: LifetimePhantom<i16>) -> LifetimePhantom<i16> {
+    loop {}
+}
+
+// This works despite current alignment resrictions because PhantomData is always align(1)
+#[repr(transparent)]
+pub struct UnitPhantom<T, U> {
+    val: T,
+    unit: PhantomData<U>,
+}
+
+pub struct Px;
+
+// CHECK: define{{.*}}float @test_UnitPhantom(float noundef %_1)
+#[no_mangle]
+pub extern "C" fn test_UnitPhantom(_: UnitPhantom<f32, Px>) -> UnitPhantom<f32, Px> {
+    loop {}
+}
+
+#[repr(transparent)]
+pub struct TwoZsts(Zst1, i8, Zst2);
+
+// CHECK: define{{( dso_local)?}} noundef{{( signext)?}} i8 @test_TwoZsts(i8 noundef{{( signext)?}} %_1)
+#[no_mangle]
+pub extern "C" fn test_TwoZsts(_: TwoZsts) -> TwoZsts {
+    loop {}
+}
+
+#[repr(transparent)]
+pub struct Nested1(Zst2, Generic<f64>);
+
+// CHECK: define{{.*}}double @test_Nested1(double noundef %_1)
+#[no_mangle]
+pub extern "C" fn test_Nested1(_: Nested1) -> Nested1 {
+    loop {}
+}
+
+#[repr(transparent)]
+pub struct Nested2(Nested1, Zst1);
+
+// CHECK: define{{.*}}double @test_Nested2(double noundef %_1)
+#[no_mangle]
+pub extern "C" fn test_Nested2(_: Nested2) -> Nested2 {
+    loop {}
+}
+
+#[repr(simd)]
+struct f32x4([f32; 4]);
+
+#[repr(transparent)]
+pub struct Vector(f32x4);
+
+// CHECK: define{{.*}}<4 x float> @test_Vector(<4 x float> %_1)
+#[no_mangle]
+#[cfg_attr(target_family = "wasm", target_feature(enable = "simd128"))]
+#[cfg_attr(target_arch = "arm", target_feature(enable = "neon"))]
+#[cfg_attr(target_arch = "x86", target_feature(enable = "sse"))]
+#[cfg_attr(target_arch = "mips", target_feature(enable = "msa"))]
+pub extern "C" fn test_Vector(_: Vector) -> Vector {
+    loop {}
+}
+
+trait Mirror {
+    type It: ?Sized;
+}
+impl<T: ?Sized> Mirror for T {
+    type It = Self;
+}
+
+#[repr(transparent)]
+pub struct StructWithProjection(<f32 as Mirror>::It);
+
+// CHECK: define{{.*}}float @test_Projection(float noundef %_1)
+#[no_mangle]
+pub extern "C" fn test_Projection(_: StructWithProjection) -> StructWithProjection {
+    loop {}
+}
+
+#[repr(transparent)]
+pub enum EnumF32 {
+    Variant(F32),
+}
+
+// CHECK: define{{.*}}float @test_EnumF32(float noundef %_1)
+#[no_mangle]
+pub extern "C" fn test_EnumF32(_: EnumF32) -> EnumF32 {
+    loop {}
+}
+
+#[repr(transparent)]
+pub enum EnumF32WithZsts {
+    Variant(Zst1, F32, Zst2),
+}
+
+// CHECK: define{{.*}}float @test_EnumF32WithZsts(float noundef %_1)
+#[no_mangle]
+pub extern "C" fn test_EnumF32WithZsts(_: EnumF32WithZsts) -> EnumF32WithZsts {
+    loop {}
+}
+
+#[repr(transparent)]
+pub union UnionF32 {
+    field: F32,
+}
+
+// CHECK: define{{.*}} float @test_UnionF32(float %_1)
+#[no_mangle]
+pub extern "C" fn test_UnionF32(_: UnionF32) -> UnionF32 {
+    loop {}
+}
+
+#[repr(transparent)]
+pub union UnionF32WithZsts {
+    zst1: Zst1,
+    field: F32,
+    zst2: Zst2,
+}
+
+// CHECK: define{{.*}}float @test_UnionF32WithZsts(float %_1)
+#[no_mangle]
+pub extern "C" fn test_UnionF32WithZsts(_: UnionF32WithZsts) -> UnionF32WithZsts {
+    loop {}
+}
+
+// All that remains to be tested are aggregates. They are tested in separate files called
+// transparent-*.rs  with `only-*` or `ignore-*` directives, because the expected LLVM IR
+// function signatures vary so much that it's not reasonably possible to cover all of them with a
+// single CHECK line.
+//
+// You may be wondering why we don't just compare the return types and argument types for equality
+// with FileCheck regex captures. Well, rustc doesn't perform newtype unwrapping on newtypes
+// containing aggregates. This is OK on all ABIs we support, but because LLVM has not gotten rid of
+// pointee types yet, the IR function signature will be syntactically different (%Foo* vs
+// %FooWrapper*).