add ptr_mask test

Author: Oneirical

src/compile_test.rs

@@ -711,6 +711,7 @@ run_test! {intrinsics,offset_of,unstable}
 run_test! {intrinsics,overflow_ops,stable}
 run_test! {intrinsics,pow_sqrt,stable}
 run_test! {intrinsics,printf,stable}
+run_test! {intrinsics,ptr_mask,stable}
 run_test! {intrinsics,ptr_offset_from_unsigned,stable}
 run_test! {intrinsics,round,stable}
 run_test! {intrinsics,size_of_val,stable}

test/intrinsics/is_val_statically_known.rs

@@ -14,11 +14,14 @@ extern crate core;
 use core::intrinsics::is_val_statically_known;
 
 fn main() {
-    test_eq!(is_val_statically_known(42), true);
-    test_eq!(is_val_statically_known([42]), false);
-    test_eq!(is_val_statically_known("42"), false);
-    test_eq!(is_val_statically_known(FortyTwo {}), false);
-    test_eq!(is_val_statically_known(FortyTwo {}.forty_two()), false);
+    test_eq!(is_val_statically_known(42), black_box(true));
+    test_eq!(is_val_statically_known([42]), black_box(false));
+    test_eq!(is_val_statically_known("42"), black_box(false));
+    test_eq!(is_val_statically_known(FortyTwo {}), black_box(false));
+    test_eq!(
+        is_val_statically_known(FortyTwo {}.forty_two()),
+        black_box(false)
+    );
 }
 
 #[derive(Copy, Clone)]

test/intrinsics/ptr_mask.rs

@@ -0,0 +1,38 @@
+#![feature(
+    lang_items,
+    adt_const_params,
+    associated_type_defaults,
+    core_intrinsics,
+    start,
+    unsized_const_params,
+    ptr_mask,
+    strict_provenance
+)]
+#![allow(internal_features, incomplete_features, unused_variables, dead_code)]
+#![no_std]
+include!("../common.rs");
+extern crate core;
+
+use core::intrinsics::ptr_mask;
+
+fn main() {
+    let v = 17_u32;
+    let ptr: *const u32 = &v;
+
+    // `u32` is 4 bytes aligned,
+    // which means that lower 2 bits are always 0.
+    let tag_mask = 0b11;
+    let mask = !tag_mask;
+
+    // We can store something in these lower bits
+    let tagged_ptr = ptr.map_addr(|a| a | 0b10);
+
+    // Get the "tag" back
+    let tag = tagged_ptr.addr() & tag_mask;
+    assert_eq!(tag, black_box(0b10));
+
+    // Note that `tagged_ptr` is unaligned, it's UB to read from it.
+    // To get original pointer `mask` can be used:
+    let masked_ptr = ptr_mask(tagged_ptr, mask);
+    assert_eq!(unsafe { *masked_ptr }, black_box(17));
+}