add codegen test

Author: tesuji

tests/codegen/issue-73825-gvn-const-local-array.rs

@@ -0,0 +1,25 @@
+// issue: <https://github.com/rust-lang/rust/issues/73825>
+//@ compile-flags: -C opt-level=1
+#![crate_type = "lib"]
+
+// CHECK-LABEL: @foo
+// CHECK-NEXT: {{.*}}:
+// CHECK-NEXT: and
+// CHECK-NEXT: getelementptr inbounds
+// CHECK-NEXT: load i32
+// CHECK-NEXT: ret i32
+#[no_mangle]
+#[rustfmt::skip]
+pub fn foo(x: usize) -> i32 {
+    let base: [i32; 64] = [
+        67, 754, 860, 559, 368, 870, 548, 972,
+        141, 731, 351, 664, 32, 4, 996, 741,
+        203, 292, 237, 480, 151, 940, 777, 540,
+        143, 587, 747, 65, 152, 517, 882, 880,
+        712, 595, 370, 901, 237, 53, 789, 785,
+        912, 650, 896, 367, 316, 392, 62, 473,
+        675, 691, 281, 192, 445, 970, 225, 425,
+        628, 324, 322, 206, 912, 867, 462, 92
+    ];
+    base[x % 64]
+}