Fix issue12118: Return value/use extra::test::black_box in benchmarks that are optimised to nothing

src/libcollections/bitv.rs

@@ -1562,6 +1562,7 @@ mod tests {
         let mut bitv = 0 as uint;
         b.iter(|| {
             bitv |= (1 << ((r.next_u32() as uint) % uint::BITS));
+            &bitv
         })
     }
 
@@ -1571,6 +1572,7 @@ mod tests {
         let mut bitv = SmallBitv::new(uint::BITS);
         b.iter(|| {
             bitv.set((r.next_u32() as uint) % uint::BITS, true);
+            &bitv
         })
     }
 
@@ -1580,6 +1582,7 @@ mod tests {
         let mut bitv = BigBitv::new(~[0]);
         b.iter(|| {
             bitv.set((r.next_u32() as uint) % uint::BITS, true);
+            &bitv
         })
     }
 
@@ -1591,6 +1594,7 @@ mod tests {
         let mut bitv = BigBitv::new(storage);
         b.iter(|| {
             bitv.set((r.next_u32() as uint) % BENCH_BITS, true);
+            &bitv
         })
     }
 
@@ -1600,6 +1604,7 @@ mod tests {
         let mut bitv = Bitv::new(BENCH_BITS, false);
         b.iter(|| {
             bitv.set((r.next_u32() as uint) % BENCH_BITS, true);
+            &bitv
         })
     }
 
@@ -1609,6 +1614,7 @@ mod tests {
         let mut bitv = Bitv::new(uint::BITS, false);
         b.iter(|| {
             bitv.set((r.next_u32() as uint) % uint::BITS, true);
+            &bitv
         })
     }
 
@@ -1618,6 +1624,7 @@ mod tests {
         let mut bitv = BitvSet::new();
         b.iter(|| {
             bitv.insert((r.next_u32() as uint) % uint::BITS);
+            &bitv
         })
     }
 
@@ -1627,6 +1634,7 @@ mod tests {
         let mut bitv = BitvSet::new();
         b.iter(|| {
             bitv.insert((r.next_u32() as uint) % BENCH_BITS);
+            &bitv
         })
     }
 

src/libcollections/deque.rs

@@ -115,8 +115,9 @@ pub mod bench {
         // measure
         let mut i = 0;
         bh.iter(|| {
-            map.find(&i);
+            let x = map.find(&i);
             i = (i + 1) % n;
+            x
         })
      }
 }

src/libstd/io/buffered.rs

@@ -565,14 +565,14 @@ mod test {
     #[bench]
     fn bench_buffered_reader(bh: &mut Harness) {
         bh.iter(|| {
-            BufferedReader::new(NullStream);
+            BufferedReader::new(NullStream)
         });
     }
 
     #[bench]
     fn bench_buffered_writer(bh: &mut Harness) {
         bh.iter(|| {
-            BufferedWriter::new(NullStream);
+            BufferedWriter::new(NullStream)
         });
     }
 

src/libstd/mem.rs

@@ -292,15 +292,15 @@ mod bench {
         let s = Struct { field: 10 };
         let t = &s as &Trait;
         bh.iter(|| {
-            t.method();
+            t.method()
         });
     }
 
     #[bench]
     fn trait_static_method_call(bh: &mut BenchHarness) {
         let s = Struct { field: 10 };
         bh.iter(|| {
-            s.method();
+            s.method()
         });
     }
 
@@ -310,21 +310,21 @@ mod bench {
     fn match_option_some(bh: &mut BenchHarness) {
         let x = Some(10);
         bh.iter(|| {
-            let _q = match x {
+            match x {
                 Some(y) => y,
                 None => 11
-            };
+            }
         });
     }
 
     #[bench]
     fn match_vec_pattern(bh: &mut BenchHarness) {
         let x = [1,2,3,4,5,6];
         bh.iter(|| {
-            let _q = match x {
+            match x {
                 [1,2,3,..] => 10,
                 _ => 11
-            };
+            }
         });
     }
 }

src/libstd/rt/global_heap.rs

@@ -140,14 +140,14 @@ mod bench {
     #[bench]
     fn alloc_owned_small(bh: &mut BenchHarness) {
         bh.iter(|| {
-            ~10;
+            ~10
         })
     }
 
     #[bench]
     fn alloc_owned_big(bh: &mut BenchHarness) {
         bh.iter(|| {
-            ~[10, ..1000];
+            ~[10, ..1000]
         })
     }
 }

src/libstd/str.rs

@@ -4356,7 +4356,7 @@ mod bench {
 
         assert_eq!(100, s.len());
         bh.iter(|| {
-            let _ = is_utf8(s);
+            is_utf8(s)
         });
     }
 
@@ -4365,7 +4365,7 @@ mod bench {
         let s = bytes!("𐌀𐌖𐌋𐌄𐌑𐌉ปรدولة الكويتทศไทย中华𐍅𐌿𐌻𐍆𐌹𐌻𐌰");
         assert_eq!(100, s.len());
         bh.iter(|| {
-            let _ = is_utf8(s);
+            is_utf8(s)
         });
     }
 
@@ -4408,7 +4408,7 @@ mod bench {
     #[bench]
     fn bench_with_capacity(bh: &mut BenchHarness) {
         bh.iter(|| {
-            let _ = with_capacity(100);
+            with_capacity(100)
         });
     }
 

src/libstd/vec.rs

@@ -4385,22 +4385,23 @@ mod bench {
         let mut vec: ~[uint] = ~[0u];
         bh.iter(|| {
             vec.push(0);
+            &vec
         })
     }
 
     #[bench]
     fn starts_with_same_vector(bh: &mut BenchHarness) {
         let vec: ~[uint] = vec::from_fn(100, |i| i);
         bh.iter(|| {
-            vec.starts_with(vec);
+            vec.starts_with(vec)
         })
     }
 
     #[bench]
     fn starts_with_single_element(bh: &mut BenchHarness) {
         let vec: ~[uint] = ~[0u];
         bh.iter(|| {
-            vec.starts_with(vec);
+            vec.starts_with(vec)
         })
     }
 
@@ -4410,23 +4411,23 @@ mod bench {
         let mut match_vec: ~[uint] = vec::from_fn(99, |i| i);
         match_vec.push(0);
         bh.iter(|| {
-            vec.starts_with(match_vec);
+            vec.starts_with(match_vec)
         })
     }
 
     #[bench]
     fn ends_with_same_vector(bh: &mut BenchHarness) {
         let vec: ~[uint] = vec::from_fn(100, |i| i);
         bh.iter(|| {
-            vec.ends_with(vec);
+            vec.ends_with(vec)
         })
     }
 
     #[bench]
     fn ends_with_single_element(bh: &mut BenchHarness) {
         let vec: ~[uint] = ~[0u];
         bh.iter(|| {
-            vec.ends_with(vec);
+            vec.ends_with(vec)
         })
     }
 
@@ -4436,15 +4437,15 @@ mod bench {
         let mut match_vec: ~[uint] = vec::from_fn(100, |i| i);
         match_vec[0] = 200;
         bh.iter(|| {
-            vec.starts_with(match_vec);
+            vec.starts_with(match_vec)
         })
     }
 
     #[bench]
     fn contains_last_element(bh: &mut BenchHarness) {
         let vec: ~[uint] = vec::from_fn(100, |i| i);
         bh.iter(|| {
-                vec.contains(&99u);
+            vec.contains(&99u)
         })
     }
 
@@ -4464,13 +4465,14 @@ mod bench {
                 ptr::set_memory(vp, 0, 1024);
                 v.set_len(1024);
             }
+            v
         });
     }
 
     #[bench]
     fn zero_1kb_fixed_repeat(bh: &mut BenchHarness) {
         bh.iter(|| {
-            let _v: ~[u8] = ~[0u8, ..1024];
+            ~[0u8, ..1024]
         });
     }
 
@@ -4499,6 +4501,7 @@ mod bench {
             for x in v.mut_iter() {
                 *x = 0;
             }
+            v
         });
     }