1 files changed, 28 insertions, 0 deletions
diff --git a/tests/codegen-llvm/adjustments.rs b/tests/codegen-llvm/adjustments.rs
new file mode 100644
index 00000000000..7f7831def08
--- /dev/null
+++ b/tests/codegen-llvm/adjustments.rs
@@ -0,0 +1,28 @@
+//@ 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 { ptr, [[USIZE]] } poison, ptr %x.0, 0
+    // CHECK: %1 = insertvalue { ptr, [[USIZE]] } %0, [[USIZE]] %x.1, 1
+    // CHECK: ret { 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)
+}