Add codegen test for integers compare

src/test/codegen/integer-cmp.rs

@@ -0,0 +1,28 @@
+// This is test for more optimal Ord implementation for integers.
+// See <https://github.com/rust-lang/rust/issues/63758> for more info.
+
+// compile-flags: -C opt-level=3
+
+#![crate_type = "lib"]
+
+use std::cmp::Ordering;
+
+// CHECK-LABEL: @cmp_signed
+#[no_mangle]
+pub fn cmp_signed(a: i64, b: i64) -> Ordering {
+// CHECK: icmp slt
+// CHECK: icmp sgt
+// CHECK: zext i1
+// CHECK: select i1
+    a.cmp(&b)
+}
+
+// CHECK-LABEL: @cmp_unsigned
+#[no_mangle]
+pub fn cmp_unsigned(a: u32, b: u32) -> Ordering {
+// CHECK: icmp ult
+// CHECK: icmp ugt
+// CHECK: zext i1
+// CHECK: select i1
+    a.cmp(&b)
+}