Add codegen test for issue 63646

tests/codegen/range_to_inclusive.rs

@@ -0,0 +1,28 @@
+//! Test that `RangeTo` and `RangeToInclusive` generate identical
+//! (and optimal) code; #63646
+//@ compile-flags: -O -Zmerge-functions=disabled
+#![crate_type = "lib"]
+
+#[no_mangle]
+// CHECK-LABEL: range_to(
+pub fn range_to(a: i32, mut b: i32) -> i32 {
+    // CHECK: %1 = and i32 %0, %a
+    // CHECK-NEXT: ret i32 %1
+    for _ in 0..65 {
+        b &= a;
+    }
+
+    b
+}
+
+#[no_mangle]
+// CHECK-LABEL: range_to_inclusive(
+pub fn range_to_inclusive(a: i32, mut b: i32) -> i32 {
+    // CHECK: %1 = and i32 %0, %a
+    // CHECK-NEXT: ret i32 %1
+    for _ in 0..=64 {
+        b &= a;
+    }
+
+    b
+}