From 82a79b99e1279ad72cb93c2ad10c6be1facaca4a Mon Sep 17 00:00:00 2001
From: KonaeAkira <longtruong2411@gmail.com>
Date: Fri, 14 Mar 2025 01:27:07 +0100
Subject: [PATCH] Add codegen test for modulo with power-of-two divisor

---
 tests/codegen/issues/issue-129795.rs | 16 ++++++++++++++++
 1 file changed, 16 insertions(+)
 create mode 100644 tests/codegen/issues/issue-129795.rs

diff --git a/tests/codegen/issues/issue-129795.rs b/tests/codegen/issues/issue-129795.rs
new file mode 100644
index 00000000000..7346227c53f
--- /dev/null
+++ b/tests/codegen/issues/issue-129795.rs
@@ -0,0 +1,16 @@
+//@ compile-flags: -Copt-level=3
+//@ min-llvm-version: 20
+#![crate_type = "lib"]
+
+// Ensure that a modulo operation with an operand that is known to be a power-of-two is properly optimized.
+
+// CHECK-LABEL: @modulo_with_power_of_two_divisor
+// CHECK: add i64 %divisor, -1
+// CHECK-NEXT: and i64
+// CHECK-NEXT: ret i64
+#[no_mangle]
+pub fn modulo_with_power_of_two_divisor(dividend: u64, divisor: u64) -> u64 {
+    assert!(divisor.is_power_of_two());
+    // should be optimized to (dividend & (divisor - 1))
+    dividend % divisor
+}