1 files changed, 63 insertions, 0 deletions
diff --git a/src/test/codegen/issue-45222.rs b/src/test/codegen/issue-45222.rs
new file mode 100644
index 000000000..e9b05e648
--- /dev/null
+++ b/src/test/codegen/issue-45222.rs
@@ -0,0 +1,63 @@
+// compile-flags: -O
+// ignore-debug: the debug assertions get in the way
+
+#![crate_type = "lib"]
+
+// verify that LLVM recognizes a loop involving 0..=n and will const-fold it.
+
+// Example from original issue #45222
+
+fn foo2(n: u64) -> u64 {
+    let mut count = 0;
+    for _ in 0..n {
+        for j in (0..=n).rev() {
+            count += j;
+        }
+    }
+    count
+}
+
+// CHECK-LABEL: @check_foo2
+#[no_mangle]
+pub fn check_foo2() -> u64 {
+    // CHECK: ret i64 500005000000000
+    foo2(100000)
+}
+
+// Simplified example of #45222
+//
+// Temporarily disabled in #68835 to fix a soundness hole.
+//
+// fn triangle_inc(n: u64) -> u64 {
+//     let mut count = 0;
+//     for j in 0 ..= n {
+//         count += j;
+//     }
+//     count
+// }
+//
+// // COMMENTEDCHECK-LABEL: @check_triangle_inc
+// #[no_mangle]
+// pub fn check_triangle_inc() -> u64 {
+//     // COMMENTEDCHECK: ret i64 5000050000
+//     triangle_inc(100000)
+// }
+
+// Demo in #48012
+
+fn foo3r(n: u64) -> u64 {
+    let mut count = 0;
+    (0..n).for_each(|_| {
+        (0..=n).rev().for_each(|j| {
+            count += j;
+        })
+    });
+    count
+}
+
+// CHECK-LABEL: @check_foo3r
+#[no_mangle]
+pub fn check_foo3r() -> u64 {
+    // CHECK: ret i64 500050000000
+    foo3r(10000)
+}