Optimize PartialOrd le

AngelicosPhosphoros · AngelicosPhosphoros · commit 284bf26ecf2b · 2021-04-04T20:37:48.000+03:00
Closes rust-lang#73338 This change stops default implementation of `le()` method from generating jumps.
diff --git a/core/src/cmp.rs b/core/src/cmp.rs
@@ -981,7 +981,8 @@ pub trait PartialOrd<Rhs: ?Sized = Self>: PartialEq<Rhs> {
     #[must_use]
     #[stable(feature = "rust1", since = "1.0.0")]
     fn le(&self, other: &Rhs) -> bool {
-        matches!(self.partial_cmp(other), Some(Less | Equal))
+        // Pattern `Some(Less | Eq)` optimizes worse than negating `None | Some(Greater)`.
+        !matches!(self.partial_cmp(other), None | Some(Greater))
     }
 
     /// This method tests greater than (for `self` and `other`) and is used by the `>` operator.

Original file line number	Diff line number	Diff line change
`@@ -981,7 +981,8 @@ pub trait PartialOrd<Rhs: ?Sized = Self>: PartialEq<Rhs> {`
`981`	`981`	`#[must_use]`
`982`	`982`	`#[stable(feature = "rust1", since = "1.0.0")]`
`983`	`983`	`fn le(&self, other: &Rhs) -> bool {`
`984`		`- matches!(self.partial_cmp(other), Some(Less \| Equal))`
	`984`	+ // Pattern `Some(Less \| Eq)` optimizes worse than negating `None \| Some(Greater)`.
	`985`	`+ !matches!(self.partial_cmp(other), None \| Some(Greater))`
`985`	`986`	`}`
`986`	`987`
`987`	`988`	/// This method tests greater than (for `self` and `other`) and is used by the `>` operator.