Auto merge of rust-lang#132238 - Urgau:midpoint-i64-hackers-impl, r=joboet

bors · bors · commit 8c0bdb3e115f · 2024-10-30T02:26:18.000Z
Use Hacker's Delight impl in `i64::midpoint` instead of wide `i128` impl This PR switches `i64::midpoint` and (`isize::midpoint` where `isize == i64`) to using our Hacker's Delight impl instead of wide `i128` implementation. As LLVM seems to be outperformed by the complexity of signed 128-bits number compared to our Hacker's Delight implementation.[^1] It doesn't seems like it's an improvement for the other sizes[^2], so we let them with the wide implementation. [^1]: https://rust.godbolt.org/z/ravE75EYj [^2]: https://rust.godbolt.org/z/fzr171zKh r? libs
diff --git a/core/src/num/mod.rs b/core/src/num/mod.rs
@@ -429,7 +429,7 @@ impl i64 {
         from_xe_bytes_doc = "",
         bound_condition = "",
     }
-    midpoint_impl! { i64, i128, signed }
+    midpoint_impl! { i64, signed }
 }
 
 impl i128 {
@@ -530,7 +530,7 @@ impl isize {
         from_xe_bytes_doc = usize_isize_from_xe_bytes_doc!(),
         bound_condition = " on 64-bit targets",
     }
-    midpoint_impl! { isize, i128, signed }
+    midpoint_impl! { isize, signed }
 }
 
 /// If the 6th bit is set ascii is lower case.

Original file line number	Diff line number	Diff line change
`@@ -429,7 +429,7 @@ impl i64 {`
`429`	`429`	`from_xe_bytes_doc = "",`
`430`	`430`	`bound_condition = "",`
`431`	`431`	`}`
`432`		`- midpoint_impl! { i64, i128, signed }`
	`432`	`+ midpoint_impl! { i64, signed }`
`433`	`433`	`}`
`434`	`434`
`435`	`435`	`impl i128 {`
`@@ -530,7 +530,7 @@ impl isize {`
`530`	`530`	`from_xe_bytes_doc = usize_isize_from_xe_bytes_doc!(),`
`531`	`531`	`bound_condition = " on 64-bit targets",`
`532`	`532`	`}`
`533`		`- midpoint_impl! { isize, i128, signed }`
	`533`	`+ midpoint_impl! { isize, signed }`
`534`	`534`	`}`
`535`	`535`
`536`	`536`	`/// If the 6th bit is set ascii is lower case.`