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Optimize comparison functions of Iterator
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Replaced matching on tuples which led to less performant code generation.
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@lezgomatt
lezgomatt committed Oct 3, 2017
1 parent 8891044 commit 3264c83
Showing 1 changed file with 114 additions and 72 deletions.
186 changes: 114 additions & 72 deletions src/libcore/iter/iterator.rs
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Original file line number Diff line number Diff line change
Expand Up @@ -2059,14 +2059,23 @@ pub trait Iterator {
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,
}
}
}
Expand All @@ -2082,14 +2091,23 @@ pub trait Iterator {
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,
}
}
}
Expand All @@ -2105,11 +2123,17 @@ pub trait Iterator {
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 }
}
}

Expand All @@ -2124,11 +2148,17 @@ pub trait Iterator {
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 }
}
}

Expand All @@ -2143,18 +2173,21 @@ pub trait Iterator {
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,
}
}
}
Expand All @@ -2170,18 +2203,21 @@ pub trait Iterator {
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,
}
}
}
Expand All @@ -2197,18 +2233,21 @@ pub trait Iterator {
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,
}
}
}
Expand All @@ -2224,18 +2263,21 @@ pub trait Iterator {
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,
}
}
}
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