bjoernager/rust
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Avoid some tuple destructuring.

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Surprisingly, this is a non-trivial performance win.
This commit is contained in:
Nicholas Nethercote 2022-04-20 16:34:33 +10:00
parent 880318c70a
commit 7a89255b20
1 changed files with 7 additions and 5 deletions
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12
compiler/rustc_parse/src/parser/mod.rs
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@ -994,22 +994,24 @@ impl<'a> Parser<'a> {
/// Advance the parser by one token. /// Advance the parser by one token.
pub fn bump(&mut self) { pub fn bump(&mut self) {
let (mut next, spacing) = self.token_cursor.inlined_next(self.desugar_doc_comments); // Note: destructuring here would give nicer code, but it was found in #96210 to be slower
// than `.0`/`.1` access.
let mut next = self.token_cursor.inlined_next(self.desugar_doc_comments);
self.token_cursor.num_next_calls += 1; self.token_cursor.num_next_calls += 1;
// We've retrieved an token from the underlying // We've retrieved an token from the underlying
// cursor, so we no longer need to worry about // cursor, so we no longer need to worry about
// an unglued token. See `break_and_eat` for more details // an unglued token. See `break_and_eat` for more details
self.token_cursor.break_last_token = false; self.token_cursor.break_last_token = false;
if next.span.is_dummy() { if next.0.span.is_dummy() {
// Tweak the location for better diagnostics, but keep syntactic context intact. // Tweak the location for better diagnostics, but keep syntactic context intact.
let fallback_span = self.token.span; let fallback_span = self.token.span;
next.span = fallback_span.with_ctxt(next.span.ctxt()); next.0.span = fallback_span.with_ctxt(next.0.span.ctxt());
} }
debug_assert!(!matches!( debug_assert!(!matches!(
next.kind, next.0.kind,
token::OpenDelim(token::NoDelim) | token::CloseDelim(token::NoDelim) token::OpenDelim(token::NoDelim) | token::CloseDelim(token::NoDelim)
)); ));
self.inlined_bump_with((next, spacing)) self.inlined_bump_with(next)
} }
/// Look-ahead `dist` tokens of `self.token` and get access to that token there. /// Look-ahead `dist` tokens of `self.token` and get access to that token there.