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Optimize comparison functions of Iterator

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Replaced matching on tuples which led to less performant code generation.
This commit is contained in:
Matt
2017-10-04 00:55:57 +08:00
parent 8891044e89
commit 3264c836bb
1 changed files with 114 additions and 72 deletions
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src/libcore/iter/iterator.rs
+114 -72
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@@ -2059,14 +2059,23 @@ fn cmp<I>(mut self, other: I) -> Ordering where
let mut other = other.into_iter();
loop {
match (self.next(), other.next()) {
(None, None) => return Ordering::Equal,
(None, _ ) => return Ordering::Less,
(_ , None) => return Ordering::Greater,
(Some(x), Some(y)) => match x.cmp(&y) {
Ordering::Equal => (),
non_eq => return non_eq,
let x = match self.next() {
None => if other.next().is_none() {
return Ordering::Equal
} else {
return Ordering::Less
},
Some(val) => val,
};
let y = match other.next() {
None => return Ordering::Greater,
Some(val) => val,
};
match x.cmp(&y) {
Ordering::Equal => (),
non_eq => return non_eq,
}
}
}
@@ -2082,14 +2091,23 @@ fn partial_cmp<I>(mut self, other: I) -> Option<Ordering> where
let mut other = other.into_iter();
loop {
match (self.next(), other.next()) {
(None, None) => return Some(Ordering::Equal),
(None, _ ) => return Some(Ordering::Less),
(_ , None) => return Some(Ordering::Greater),
(Some(x), Some(y)) => match x.partial_cmp(&y) {
Some(Ordering::Equal) => (),
non_eq => return non_eq,
let x = match self.next() {
None => if other.next().is_none() {
return Some(Ordering::Equal)
} else {
return Some(Ordering::Less)
},
Some(val) => val,
};
let y = match other.next() {
None => return Some(Ordering::Greater),
Some(val) => val,
};
match x.partial_cmp(&y) {
Some(Ordering::Equal) => (),
non_eq => return non_eq,
}
}
}
@@ -2105,11 +2123,17 @@ fn eq<I>(mut self, other: I) -> bool where
let mut other = other.into_iter();
loop {
match (self.next(), other.next()) {
(None, None) => return true,
(None, _) | (_, None) => return false,
(Some(x), Some(y)) => if x != y { return false },
}
let x = match self.next() {
None => return other.next().is_none(),
Some(val) => val,
};
let y = match other.next() {
None => return false,
Some(val) => val,
};
if x != y { return false }
}
}
@@ -2124,11 +2148,17 @@ fn ne<I>(mut self, other: I) -> bool where
let mut other = other.into_iter();
loop {
match (self.next(), other.next()) {
(None, None) => return false,
(None, _) | (_, None) => return true,
(Some(x), Some(y)) => if x.ne(&y) { return true },
}
let x = match self.next() {
None => return other.next().is_some(),
Some(val) => val,
};
let y = match other.next() {
None => return true,
Some(val) => val,
};
if x != y { return true }
}
}
@@ -2143,18 +2173,21 @@ fn lt<I>(mut self, other: I) -> bool where
let mut other = other.into_iter();
loop {
match (self.next(), other.next()) {
(None, None) => return false,
(None, _ ) => return true,
(_ , None) => return false,
(Some(x), Some(y)) => {
match x.partial_cmp(&y) {
Some(Ordering::Less) => return true,
Some(Ordering::Equal) => {}
Some(Ordering::Greater) => return false,
None => return false,
}
},
let x = match self.next() {
None => return other.next().is_some(),
Some(val) => val,
};
let y = match other.next() {
None => return false,
Some(val) => val,
};
match x.partial_cmp(&y) {
Some(Ordering::Less) => return true,
Some(Ordering::Equal) => (),
Some(Ordering::Greater) => return false,
None => return false,
}
}
}
@@ -2170,18 +2203,21 @@ fn le<I>(mut self, other: I) -> bool where
let mut other = other.into_iter();
loop {
match (self.next(), other.next()) {
(None, None) => return true,
(None, _ ) => return true,
(_ , None) => return false,
(Some(x), Some(y)) => {
match x.partial_cmp(&y) {
Some(Ordering::Less) => return true,
Some(Ordering::Equal) => {}
Some(Ordering::Greater) => return false,
None => return false,
}
},
let x = match self.next() {
None => { other.next(); return true; },
Some(val) => val,
};
let y = match other.next() {
None => return false,
Some(val) => val,
};
match x.partial_cmp(&y) {
Some(Ordering::Less) => return true,
Some(Ordering::Equal) => (),
Some(Ordering::Greater) => return false,
None => return false,
}
}
}
@@ -2197,18 +2233,21 @@ fn gt<I>(mut self, other: I) -> bool where
let mut other = other.into_iter();
loop {
match (self.next(), other.next()) {
(None, None) => return false,
(None, _ ) => return false,
(_ , None) => return true,
(Some(x), Some(y)) => {
match x.partial_cmp(&y) {
Some(Ordering::Less) => return false,
Some(Ordering::Equal) => {}
Some(Ordering::Greater) => return true,
None => return false,
}
}
let x = match self.next() {
None => { other.next(); return false; },
Some(val) => val,
};
let y = match other.next() {
None => return true,
Some(val) => val,
};
match x.partial_cmp(&y) {
Some(Ordering::Less) => return false,
Some(Ordering::Equal) => (),
Some(Ordering::Greater) => return true,
None => return false,
}
}
}
@@ -2224,18 +2263,21 @@ fn ge<I>(mut self, other: I) -> bool where
let mut other = other.into_iter();
loop {
match (self.next(), other.next()) {
(None, None) => return true,
(None, _ ) => return false,
(_ , None) => return true,
(Some(x), Some(y)) => {
match x.partial_cmp(&y) {
Some(Ordering::Less) => return false,
Some(Ordering::Equal) => {}
Some(Ordering::Greater) => return true,
None => return false,
}
},
let x = match self.next() {
None => return other.next().is_none(),
Some(val) => val,
};
let y = match other.next() {
None => return true,
Some(val) => val,
};
match x.partial_cmp(&y) {
Some(Ordering::Less) => return false,
Some(Ordering::Equal) => (),
Some(Ordering::Greater) => return true,
None => return false,
}
}
}