1 files changed, 28 insertions, 0 deletions
diff --git a/tests/codegen/slice-iter-len-eq-zero.rs b/tests/codegen/slice-iter-len-eq-zero.rs
new file mode 100644
index 000000000..894b0ec3d
--- /dev/null
+++ b/tests/codegen/slice-iter-len-eq-zero.rs
@@ -0,0 +1,28 @@
+// no-system-llvm
+// compile-flags: -O
+// ignore-debug: the debug assertions add extra comparisons
+#![crate_type = "lib"]
+
+type Demo = [u8; 3];
+
+// CHECK-LABEL: @slice_iter_len_eq_zero
+#[no_mangle]
+pub fn slice_iter_len_eq_zero(y: std::slice::Iter<'_, Demo>) -> bool {
+    // CHECK-NOT: sub
+    // CHECK: %2 = icmp eq {{i8\*|ptr}} {{%1|%0}}, {{%1|%0}}
+    // CHECK: ret i1 %2
+    y.len() == 0
+}
+
+// CHECK-LABEL: @array_into_iter_len_eq_zero
+#[no_mangle]
+pub fn array_into_iter_len_eq_zero(y: std::array::IntoIter<Demo, 123>) -> bool {
+    // This should be able to just check that the indexes are equal, and not
+    // need any subtractions or comparisons to handle `start > end`.
+
+    // CHECK-NOT: icmp
+    // CHECK-NOT: sub
+    // CHECK: %1 = icmp eq {{i16|i32|i64}}
+    // CHECK: ret i1 %1
+    y.len() == 0
+}