From 99fd9cb6971fc68d6865c2e2cf7722030001f609 Mon Sep 17 00:00:00 2001 From: Scott McMurray Date: Sun, 16 Apr 2023 04:01:34 -0700 Subject: [PATCH] Remove the loop in `Align::from_bytes` Perf is almost certainly irrelevant, but might as well simplify it, since `trailing_zeros` does exactly what's needed. --- compiler/rustc_abi/src/lib.rs | 11 ++++------- 1 file changed, 4 insertions(+), 7 deletions(-) diff --git a/compiler/rustc_abi/src/lib.rs b/compiler/rustc_abi/src/lib.rs index b0c0ee942ea..7a3defd2a5d 100644 --- a/compiler/rustc_abi/src/lib.rs +++ b/compiler/rustc_abi/src/lib.rs @@ -665,15 +665,12 @@ impl Align { format!("`{}` is too large", align) } - let mut bytes = align; - let mut pow2: u8 = 0; - while (bytes & 1) == 0 { - pow2 += 1; - bytes >>= 1; - } - if bytes != 1 { + let tz = align.trailing_zeros(); + if align != (1 << tz) { return Err(not_power_of_2(align)); } + + let pow2 = tz as u8; if pow2 > Self::MAX.pow2 { return Err(too_large(align)); }