diff options
| author | Samuel Tardieu <sam@rfc1149.net> | 2025-07-16 17:06:38 +0200 |
|---|---|---|
| committer | GitHub <noreply@github.com> | 2025-07-16 17:06:38 +0200 |
| commit | 37aba8388e93c9beeb092cbfa4540555d67a0af9 (patch) | |
| tree | c0bf69c71c431a85b7a2dd2a712a4342d953dd17 | |
| parent | 9f2015d3d3884e17044be61926292f7b7a41bdc8 (diff) | |
| parent | f1b5a5638ec3aba301dc5a50daccb4c1ed69ac78 (diff) | |
Rollup merge of #143355 - hkBst:cleanup-shift-double-bitmask, r=Mark-Simulacrum
wrapping shift: remove first bitmask and table
```rust
#[inline(always)]
pub const fn wrapping_shl(self, rhs: u32) -> Self {
// SAFETY: the masking by the bitsize of the type ensures that we do not shift
// out of bounds
unsafe {
self.unchecked_shl(rhs & (Self::BITS - 1))
}
}
```
already does the bitmask, so it seems unnecessary here.
More context: internals.rust-lang.org/t/wrapping-shift-operator-code-doing-bitmasking-twice/23167
| -rw-r--r-- | library/core/src/num/wrapping.rs | 48 |
1 files changed, 6 insertions, 42 deletions
diff --git a/library/core/src/num/wrapping.rs b/library/core/src/num/wrapping.rs index 55fa91d0b9f..c460f38bd2e 100644 --- a/library/core/src/num/wrapping.rs +++ b/library/core/src/num/wrapping.rs @@ -94,9 +94,9 @@ macro_rules! sh_impl_signed { #[inline] fn shl(self, other: $f) -> Wrapping<$t> { if other < 0 { - Wrapping(self.0.wrapping_shr((-other & self::shift_max::$t as $f) as u32)) + Wrapping(self.0.wrapping_shr(-other as u32)) } else { - Wrapping(self.0.wrapping_shl((other & self::shift_max::$t as $f) as u32)) + Wrapping(self.0.wrapping_shl(other as u32)) } } } @@ -119,9 +119,9 @@ macro_rules! sh_impl_signed { #[inline] fn shr(self, other: $f) -> Wrapping<$t> { if other < 0 { - Wrapping(self.0.wrapping_shl((-other & self::shift_max::$t as $f) as u32)) + Wrapping(self.0.wrapping_shl(-other as u32)) } else { - Wrapping(self.0.wrapping_shr((other & self::shift_max::$t as $f) as u32)) + Wrapping(self.0.wrapping_shr(other as u32)) } } } @@ -147,7 +147,7 @@ macro_rules! sh_impl_unsigned { #[inline] fn shl(self, other: $f) -> Wrapping<$t> { - Wrapping(self.0.wrapping_shl((other & self::shift_max::$t as $f) as u32)) + Wrapping(self.0.wrapping_shl(other as u32)) } } forward_ref_binop! { impl Shl, shl for Wrapping<$t>, $f, @@ -168,7 +168,7 @@ macro_rules! sh_impl_unsigned { #[inline] fn shr(self, other: $f) -> Wrapping<$t> { - Wrapping(self.0.wrapping_shr((other & self::shift_max::$t as $f) as u32)) + Wrapping(self.0.wrapping_shr(other as u32)) } } forward_ref_binop! { impl Shr, shr for Wrapping<$t>, $f, @@ -1052,39 +1052,3 @@ macro_rules! wrapping_int_impl_unsigned { } wrapping_int_impl_unsigned! { usize u8 u16 u32 u64 u128 } - -mod shift_max { - #![allow(non_upper_case_globals)] - - #[cfg(target_pointer_width = "16")] - mod platform { - pub(crate) const usize: u32 = super::u16; - pub(crate) const isize: u32 = super::i16; - } - - #[cfg(target_pointer_width = "32")] - mod platform { - pub(crate) const usize: u32 = super::u32; - pub(crate) const isize: u32 = super::i32; - } - - #[cfg(target_pointer_width = "64")] - mod platform { - pub(crate) const usize: u32 = super::u64; - pub(crate) const isize: u32 = super::i64; - } - - pub(super) const i8: u32 = (1 << 3) - 1; - pub(super) const i16: u32 = (1 << 4) - 1; - pub(super) const i32: u32 = (1 << 5) - 1; - pub(super) const i64: u32 = (1 << 6) - 1; - pub(super) const i128: u32 = (1 << 7) - 1; - pub(super) use self::platform::isize; - - pub(super) const u8: u32 = i8; - pub(super) const u16: u32 = i16; - pub(super) const u32: u32 = i32; - pub(super) const u64: u32 = i64; - pub(super) const u128: u32 = i128; - pub(super) use self::platform::usize; -} |
