1 files changed, 29 insertions, 0 deletions
diff --git a/tests/codegen/adjustments.rs b/tests/codegen/adjustments.rs
new file mode 100644
index 000000000..6d2247517
--- /dev/null
+++ b/tests/codegen/adjustments.rs
@@ -0,0 +1,29 @@
+// compile-flags: -C no-prepopulate-passes -Copt-level=0
+
+#![crate_type = "lib"]
+
+// Hack to get the correct size for the length part in slices
+// CHECK: @helper([[USIZE:i[0-9]+]] %_1)
+#[no_mangle]
+pub fn helper(_: usize) {
+}
+
+// CHECK-LABEL: @no_op_slice_adjustment
+#[no_mangle]
+pub fn no_op_slice_adjustment(x: &[u8]) -> &[u8] {
+    // We used to generate an extra alloca and memcpy for the block's trailing expression value, so
+    // check that we copy directly to the return value slot
+// CHECK: %0 = insertvalue { {{\[0 x i8\]\*|ptr}}, [[USIZE]] } undef, {{\[0 x i8\]\*|ptr}} %x.0, 0
+// CHECK: %1 = insertvalue { {{\[0 x i8\]\*|ptr}}, [[USIZE]] } %0, [[USIZE]] %x.1, 1
+// CHECK: ret { {{\[0 x i8\]\*|ptr}}, [[USIZE]] } %1
+    { x }
+}
+
+// CHECK-LABEL: @no_op_slice_adjustment2
+#[no_mangle]
+pub fn no_op_slice_adjustment2(x: &[u8]) -> &[u8] {
+    // We used to generate an extra alloca and memcpy for the function's return value, so check
+    // that there's no memcpy (the slice is written to sret_slot element-wise)
+// CHECK-NOT: call void @llvm.memcpy.
+    no_op_slice_adjustment(x)
+}