1 files changed, 69 insertions, 0 deletions
diff --git a/tests/codegen/dst-offset.rs b/tests/codegen/dst-offset.rs
new file mode 100644
index 00000000000..55212112b3d
--- /dev/null
+++ b/tests/codegen/dst-offset.rs
@@ -0,0 +1,69 @@
+//! This file tests that we correctly generate GEP instructions for DST
+//! field offsets.
+//@ compile-flags: -C no-prepopulate-passes -Copt-level=0
+
+#![crate_type = "lib"]
+
+use std::ptr::addr_of;
+
+// Hack to get the correct type for usize
+// CHECK: @helper([[USIZE:i[0-9]+]] %_1)
+#[no_mangle]
+pub fn helper(_: usize) {
+}
+
+struct Dst<T: ?Sized> {
+    x: u32,
+    y: u8,
+    z: T,
+}
+
+// CHECK: @dst_dyn_trait_offset(ptr align {{[0-9]+}} [[DATA_PTR:%.+]], ptr align {{[0-9]+}} [[VTABLE_PTR:%.+]])
+#[no_mangle]
+pub fn dst_dyn_trait_offset(s: &Dst<dyn Drop>) -> &dyn Drop {
+// The alignment of dyn trait is unknown, so we compute the offset based on align from the vtable.
+
+// CHECK: [[SIZE_PTR:%[0-9]+]] = getelementptr inbounds {{.+}} [[VTABLE_PTR]]
+// CHECK: load [[USIZE]], ptr [[SIZE_PTR]]
+// CHECK: [[ALIGN_PTR:%[0-9]+]] = getelementptr inbounds {{.+}} [[VTABLE_PTR]]
+// CHECK: load [[USIZE]], ptr [[ALIGN_PTR]]
+
+// CHECK: getelementptr inbounds i8, ptr [[DATA_PTR]]
+// CHECK-NEXT: insertvalue
+// CHECK-NEXT: insertvalue
+// CHECK-NEXT: ret
+    &s.z
+}
+
+// CHECK-LABEL: @dst_slice_offset
+#[no_mangle]
+pub fn dst_slice_offset(s: &Dst<[u16]>) -> &[u16] {
+// The alignment of [u16] is known, so we generate a GEP directly.
+
+// CHECK: start:
+// CHECK-NEXT: getelementptr inbounds i8, {{.+}}, [[USIZE]] 6
+// CHECK-NEXT: insertvalue
+// CHECK-NEXT: insertvalue
+// CHECK-NEXT: ret
+    &s.z
+}
+
+#[repr(packed)]
+struct PackedDstSlice {
+    x: u32,
+    y: u8,
+    z: [u16],
+}
+
+// CHECK-LABEL: @packed_dst_slice_offset
+#[no_mangle]
+pub fn packed_dst_slice_offset(s: &PackedDstSlice) -> *const [u16] {
+// The alignment of [u16] is known, so we generate a GEP directly.
+
+// CHECK: start:
+// CHECK-NEXT: getelementptr inbounds i8, {{.+}}, [[USIZE]] 5
+// CHECK-NEXT: insertvalue
+// CHECK-NEXT: insertvalue
+// CHECK-NEXT: ret
+    addr_of!(s.z)
+}