From 401651015d837ebfe55928692a84de37ec8a3a4b Mon Sep 17 00:00:00 2001
From: Erik Desjardins <erikdesjardins@users.noreply.github.com>
Date: Tue, 27 Feb 2024 23:14:36 -0500
Subject: [PATCH] test merging of multiple match branches that access fields of
 the same offset

---
 .../issue-121719-common-field-offset.rs       | 44 +++++++++++++++++++
 1 file changed, 44 insertions(+)
 create mode 100644 tests/codegen/issues/issue-121719-common-field-offset.rs

diff --git a/tests/codegen/issues/issue-121719-common-field-offset.rs b/tests/codegen/issues/issue-121719-common-field-offset.rs
new file mode 100644
index 00000000000..11a8aa8dcd1
--- /dev/null
+++ b/tests/codegen/issues/issue-121719-common-field-offset.rs
@@ -0,0 +1,44 @@
+//! This test checks that match branches which all access a field
+//! at the same offset are merged together.
+//!
+//@ compile-flags: -O
+#![crate_type = "lib"]
+
+#[repr(C)]
+pub struct A {
+    x: f64,
+    y: u64,
+}
+#[repr(C)]
+pub struct B {
+    x: f64,
+    y: u32,
+}
+#[repr(C)]
+pub struct C {
+    x: f64,
+    y: u16,
+}
+#[repr(C)]
+pub struct D {
+    x: f64,
+    y: u8,
+}
+
+pub enum E {
+    A(A),
+    B(B),
+    C(C),
+    D(D),
+}
+
+// CHECK-LABEL: @match_on_e
+#[no_mangle]
+pub fn match_on_e(e: &E) -> &f64 {
+    // CHECK: start:
+    // CHECK-NEXT: getelementptr
+    // CHECK-NEXT: ret
+    match e {
+        E::A(A { x, .. }) | E::B(B { x, .. }) | E::C(C { x, .. }) | E::D(D { x, .. }) => x,
+    }
+}