Function rustc_span::analyze_source_file::analyze_source_file_sse2

unsafe fn analyze_source_file_sse2(
    src: &str,
    lines: &mut Vec<RelativeBytePos>,
    multi_byte_chars: &mut Vec<MultiByteChar>,
    non_narrow_chars: &mut Vec<NonNarrowChar>
)

Available with target feature sse2 only.

Checks 16 byte chunks of text at a time. If the chunk contains something other than printable ASCII characters and newlines, the function falls back to the generic implementation. Otherwise it uses SSE2 intrinsics to quickly find all newlines.