core/num: Speed up from_str_radix() method

src/libcore/benches/num/mod.rs

@@ -10,3 +10,108 @@
 
 mod flt2dec;
 mod dec2flt;
+
+use test::Bencher;
+use std::str::FromStr;
+
+const ASCII_NUMBERS: [&str; 19] = [
+    "0",
+    "1",
+    "2",
+    "43",
+    "765",
+    "76567",
+    "987245987",
+    "-4aa32",
+    "1786235",
+    "8723095",
+    "f##5s",
+    "83638730",
+    "-2345",
+    "562aa43",
+    "-1",
+    "-0",
+    "abc",
+    "xyz",
+    "c0ffee",
+];
+
+macro_rules! from_str_bench {
+    ($mac:ident, $t:ty) => (
+        #[bench]
+        fn $mac(b: &mut Bencher) {
+            b.iter(|| {
+                ASCII_NUMBERS
+                    .iter()
+                    .cycle()
+                    .take(5_000)
+                    .filter_map(|s| <($t)>::from_str(s).ok())
+                    .max()
+            })
+        }
+    )
+}
+
+macro_rules! from_str_radix_bench {
+    ($mac:ident, $t:ty, $radix:expr) => (
+        #[bench]
+        fn $mac(b: &mut Bencher) {
+            b.iter(|| {
+                ASCII_NUMBERS
+                    .iter()
+                    .cycle()
+                    .take(5_000)
+                    .filter_map(|s| <($t)>::from_str_radix(s, $radix).ok())
+                    .max()
+            })
+        }
+    )
+}
+
+from_str_bench!(bench_u8_from_str, u8);
+from_str_radix_bench!(bench_u8_from_str_radix_2, u8, 2);
+from_str_radix_bench!(bench_u8_from_str_radix_10, u8, 10);
+from_str_radix_bench!(bench_u8_from_str_radix_16, u8, 16);
+from_str_radix_bench!(bench_u8_from_str_radix_36, u8, 36);
+
+from_str_bench!(bench_u16_from_str, u16);
+from_str_radix_bench!(bench_u16_from_str_radix_2, u16, 2);
+from_str_radix_bench!(bench_u16_from_str_radix_10, u16, 10);
+from_str_radix_bench!(bench_u16_from_str_radix_16, u16, 16);
+from_str_radix_bench!(bench_u16_from_str_radix_36, u16, 36);
+
+from_str_bench!(bench_u32_from_str, u32);
+from_str_radix_bench!(bench_u32_from_str_radix_2, u32, 2);
+from_str_radix_bench!(bench_u32_from_str_radix_10, u32, 10);
+from_str_radix_bench!(bench_u32_from_str_radix_16, u32, 16);
+from_str_radix_bench!(bench_u32_from_str_radix_36, u32, 36);
+
+from_str_bench!(bench_u64_from_str, u64);
+from_str_radix_bench!(bench_u64_from_str_radix_2, u64, 2);
+from_str_radix_bench!(bench_u64_from_str_radix_10, u64, 10);
+from_str_radix_bench!(bench_u64_from_str_radix_16, u64, 16);
+from_str_radix_bench!(bench_u64_from_str_radix_36, u64, 36);
+
+from_str_bench!(bench_i8_from_str, i8);
+from_str_radix_bench!(bench_i8_from_str_radix_2, i8, 2);
+from_str_radix_bench!(bench_i8_from_str_radix_10, i8, 10);
+from_str_radix_bench!(bench_i8_from_str_radix_16, i8, 16);
+from_str_radix_bench!(bench_i8_from_str_radix_36, i8, 36);
+
+from_str_bench!(bench_i16_from_str, i16);
+from_str_radix_bench!(bench_i16_from_str_radix_2, i16, 2);
+from_str_radix_bench!(bench_i16_from_str_radix_10, i16, 10);
+from_str_radix_bench!(bench_i16_from_str_radix_16, i16, 16);
+from_str_radix_bench!(bench_i16_from_str_radix_36, i16, 36);
+
+from_str_bench!(bench_i32_from_str, i32);
+from_str_radix_bench!(bench_i32_from_str_radix_2, i32, 2);
+from_str_radix_bench!(bench_i32_from_str_radix_10, i32, 10);
+from_str_radix_bench!(bench_i32_from_str_radix_16, i32, 16);
+from_str_radix_bench!(bench_i32_from_str_radix_36, i32, 36);
+
+from_str_bench!(bench_i64_from_str, i64);
+from_str_radix_bench!(bench_i64_from_str_radix_2, i64, 2);
+from_str_radix_bench!(bench_i64_from_str_radix_10, i64, 10);
+from_str_radix_bench!(bench_i64_from_str_radix_16, i64, 16);
+from_str_radix_bench!(bench_i64_from_str_radix_36, i64, 36);

src/libcore/num/mod.rs

@@ -4438,7 +4438,7 @@ macro_rules! from_str_radix_int_impl {
         impl FromStr for $t {
             type Err = ParseIntError;
             fn from_str(src: &str) -> Result<Self, ParseIntError> {
-                from_str_radix(src, 10)
+                <($t)>::from_str_radix(src, 10)
             }
         }
     )*}