Add two more benchmarks for strictly ASCII and non ASCII cases

library/core/benches/char/methods.rs

@@ -47,11 +47,31 @@ fn bench_to_ascii_lowercase(b: &mut Bencher) {
 }
 
 #[bench]
-fn bench_char_to_uppercase(b: &mut Bencher) {
+fn bench_ascii_mix_to_uppercase(b: &mut Bencher) {
     b.iter(|| (0..=255).cycle().take(10_000).map(|b| char::from(b).to_uppercase()).count())
 }
 
 #[bench]
-fn bench_char_to_lowercase(b: &mut Bencher) {
+fn bench_ascii_mix_to_lowercase(b: &mut Bencher) {
     b.iter(|| (0..=255).cycle().take(10_000).map(|b| char::from(b).to_lowercase()).count())
 }
+
+#[bench]
+fn bench_ascii_char_to_uppercase(b: &mut Bencher) {
+    b.iter(|| (0..=127).cycle().take(10_000).map(|b| char::from(b).to_uppercase()).count())
+}
+
+#[bench]
+fn bench_ascii_char_to_lowercase(b: &mut Bencher) {
+    b.iter(|| (0..=127).cycle().take(10_000).map(|b| char::from(b).to_lowercase()).count())
+}
+
+#[bench]
+fn bench_non_ascii_char_to_uppercase(b: &mut Bencher) {
+    b.iter(|| (128..=255).cycle().take(10_000).map(|b| char::from(b).to_uppercase()).count())
+}
+
+#[bench]
+fn bench_non_ascii_char_to_lowercase(b: &mut Bencher) {
+    b.iter(|| (128..=255).cycle().take(10_000).map(|b| char::from(b).to_lowercase()).count())
+}