diff --git a/.github/workflows/ci.yml b/.github/workflows/ci.yml
index 89809f5..87baaab 100644
--- a/.github/workflows/ci.yml
+++ b/.github/workflows/ci.yml
@@ -64,7 +64,7 @@ jobs:
     - uses: Swatinem/rust-cache@v2
     - uses: taiki-e/install-action@cargo-hack
     - name: Default features
-      run: cargo hack check --feature-powerset --locked --rust-version --ignore-private --workspace --all-targets
+      run: cargo hack check --feature-powerset --locked --rust-version --ignore-private --workspace --lib --bins
   lockfile:
     runs-on: ubuntu-latest
     steps:
diff --git a/Cargo.lock b/Cargo.lock
index 226775f..244fffd 100644
--- a/Cargo.lock
+++ b/Cargo.lock
@@ -11,12 +11,6 @@ dependencies = [
  "memchr",
 ]
 
-[[package]]
-name = "anes"
-version = "0.1.6"
-source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "4b46cbb362ab8752921c97e041f5e366ee6297bd428a31275b9fcf1e380f7299"
-
 [[package]]
 name = "annotate-snippets"
 version = "0.11.4"
@@ -24,9 +18,10 @@ dependencies = [
  "annotate-snippets",
  "anstream 0.6.15",
  "anstyle",
- "criterion",
  "difference",
+ "divan",
  "glob",
+ "memchr",
  "serde",
  "snapbox",
  "toml",
@@ -131,10 +126,10 @@ dependencies = [
 ]
 
 [[package]]
-name = "autocfg"
-version = "1.3.0"
+name = "bitflags"
+version = "1.3.2"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "0c4b4d0bd25bd0b74681c0ad21497610ce1b7c91b1022cd21c80c6fbdd9476b0"
+checksum = "bef38d45163c2f1dde094a7dfd33ccf595c92905c8f8f4fdc18d06fb1037718a"
 
 [[package]]
 name = "bstr"
@@ -146,51 +141,12 @@ dependencies = [
  "serde",
 ]
 
-[[package]]
-name = "bumpalo"
-version = "3.14.0"
-source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "7f30e7476521f6f8af1a1c4c0b8cc94f0bee37d91763d0ca2665f299b6cd8aec"
-
-[[package]]
-name = "cast"
-version = "0.3.0"
-source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "37b2a672a2cb129a2e41c10b1224bb368f9f37a2b16b612598138befd7b37eb5"
-
 [[package]]
 name = "cfg-if"
 version = "1.0.0"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "baf1de4339761588bc0619e3cbc0120ee582ebb74b53b4efbf79117bd2da40fd"
 
-[[package]]
-name = "ciborium"
-version = "0.2.2"
-source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "42e69ffd6f0917f5c029256a24d0161db17cea3997d185db0d35926308770f0e"
-dependencies = [
- "ciborium-io",
- "ciborium-ll",
- "serde",
-]
-
-[[package]]
-name = "ciborium-io"
-version = "0.2.2"
-source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "05afea1e0a06c9be33d539b876f1ce3692f4afea2cb41f740e7743225ed1c757"
-
-[[package]]
-name = "ciborium-ll"
-version = "0.2.2"
-source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "57663b653d948a338bfb3eeba9bb2fd5fcfaecb9e199e87e1eda4d9e8b240fd9"
-dependencies = [
- "ciborium-io",
- "half",
-]
-
 [[package]]
 name = "clap"
 version = "4.3.24"
@@ -212,6 +168,7 @@ dependencies = [
  "anstyle",
  "clap_lex",
  "strsim",
+ "terminal_size",
 ]
 
 [[package]]
@@ -239,83 +196,51 @@ source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "0b6a852b24ab71dffc585bcb46eaf7959d175cb865a7152e35b348d1b2960422"
 
 [[package]]
-name = "criterion"
-version = "0.5.1"
+name = "condtype"
+version = "1.3.0"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "f2b12d017a929603d80db1831cd3a24082f8137ce19c69e6447f54f5fc8d692f"
-dependencies = [
- "anes",
- "cast",
- "ciborium",
- "clap",
- "criterion-plot",
- "is-terminal",
- "itertools",
- "num-traits",
- "once_cell",
- "oorandom",
- "plotters",
- "rayon",
- "regex",
- "serde",
- "serde_derive",
- "serde_json",
- "tinytemplate",
- "walkdir",
-]
+checksum = "baf0a07a401f374238ab8e2f11a104d2851bf9ce711ec69804834de8af45c7af"
 
 [[package]]
-name = "criterion-plot"
-version = "0.5.0"
+name = "difference"
+version = "2.0.0"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "6b50826342786a51a89e2da3a28f1c32b06e387201bc2d19791f622c673706b1"
-dependencies = [
- "cast",
- "itertools",
-]
+checksum = "524cbf6897b527295dff137cec09ecf3a05f4fddffd7dfcd1585403449e74198"
 
 [[package]]
-name = "crossbeam-deque"
-version = "0.8.5"
+name = "divan"
+version = "0.1.14"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "613f8cc01fe9cf1a3eb3d7f488fd2fa8388403e97039e2f73692932e291a770d"
+checksum = "a0d567df2c9c2870a43f3f2bd65aaeb18dbce1c18f217c3e564b4fbaeb3ee56c"
 dependencies = [
- "crossbeam-epoch",
- "crossbeam-utils",
+ "cfg-if",
+ "clap",
+ "condtype",
+ "divan-macros",
+ "libc",
+ "regex-lite",
 ]
 
 [[package]]
-name = "crossbeam-epoch"
-version = "0.9.18"
+name = "divan-macros"
+version = "0.1.14"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "5b82ac4a3c2ca9c3460964f020e1402edd5753411d7737aa39c3714ad1b5420e"
+checksum = "27540baf49be0d484d8f0130d7d8da3011c32a44d4fc873368154f1510e574a2"
 dependencies = [
- "crossbeam-utils",
+ "proc-macro2",
+ "quote",
+ "syn",
 ]
 
 [[package]]
-name = "crossbeam-utils"
-version = "0.8.20"
-source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "22ec99545bb0ed0ea7bb9b8e1e9122ea386ff8a48c0922e43f36d45ab09e0e80"
-
-[[package]]
-name = "crunchy"
-version = "0.2.2"
-source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "7a81dae078cea95a014a339291cec439d2f232ebe854a9d672b796c6afafa9b7"
-
-[[package]]
-name = "difference"
-version = "2.0.0"
-source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "524cbf6897b527295dff137cec09ecf3a05f4fddffd7dfcd1585403449e74198"
-
-[[package]]
-name = "either"
-version = "1.12.0"
+name = "errno"
+version = "0.3.9"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "3dca9240753cf90908d7e4aac30f630662b02aebaa1b58a3cadabdb23385b58b"
+checksum = "534c5cf6194dfab3db3242765c03bbe257cf92f22b38f6bc0c58d59108a820ba"
+dependencies = [
+ "libc",
+ "windows-sys 0.52.0",
+]
 
 [[package]]
 name = "escape8259"
@@ -357,15 +282,6 @@ dependencies = [
  "regex-syntax",
 ]
 
-[[package]]
-name = "half"
-version = "2.2.1"
-source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "02b4af3693f1b705df946e9fe5631932443781d0aabb423b62fcd4d73f6d2fd0"
-dependencies = [
- "crunchy",
-]
-
 [[package]]
 name = "heck"
 version = "0.4.1"
@@ -404,6 +320,17 @@ dependencies = [
  "winapi-util",
 ]
 
+[[package]]
+name = "io-lifetimes"
+version = "1.0.11"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "eae7b9aee968036d54dce06cebaefd919e4472e753296daccd6d344e3e2df0c2"
+dependencies = [
+ "hermit-abi",
+ "libc",
+ "windows-sys 0.48.0",
+]
+
 [[package]]
 name = "is-terminal"
 version = "0.4.12"
@@ -424,30 +351,12 @@ dependencies = [
  "is-terminal",
 ]
 
-[[package]]
-name = "itertools"
-version = "0.10.5"
-source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "b0fd2260e829bddf4cb6ea802289de2f86d6a7a690192fbe91b3f46e0f2c8473"
-dependencies = [
- "either",
-]
-
 [[package]]
 name = "itoa"
 version = "1.0.11"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "49f1f14873335454500d59611f1cf4a4b0f786f9ac11f4312a78e4cf2566695b"
 
-[[package]]
-name = "js-sys"
-version = "0.3.69"
-source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "29c15563dc2726973df627357ce0c9ddddbea194836909d655df6a75d2cf296d"
-dependencies = [
- "wasm-bindgen",
-]
-
 [[package]]
 name = "lazy_static"
 version = "1.4.0"
@@ -472,6 +381,12 @@ dependencies = [
  "threadpool",
 ]
 
+[[package]]
+name = "linux-raw-sys"
+version = "0.3.8"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "ef53942eb7bf7ff43a617b3e2c1c4a5ecf5944a7c1bc12d7ee39bbb15e5c1519"
+
 [[package]]
 name = "log"
 version = "0.4.21"
@@ -480,9 +395,9 @@ checksum = "90ed8c1e510134f979dbc4f070f87d4313098b704861a105fe34231c70a3901c"
 
 [[package]]
 name = "memchr"
-version = "2.7.2"
+version = "2.7.4"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "6c8640c5d730cb13ebd907d8d04b52f55ac9a2eec55b440c8892f40d56c76c1d"
+checksum = "78ca9ab1a0babb1e7d5695e3530886289c18cf2f87ec19a575a0abdce112e3a3"
 
 [[package]]
 name = "normalize-line-endings"
@@ -490,15 +405,6 @@ version = "0.3.0"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "61807f77802ff30975e01f4f071c8ba10c022052f98b3294119f3e615d13e5be"
 
-[[package]]
-name = "num-traits"
-version = "0.2.19"
-source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "071dfc062690e90b734c0b2273ce72ad0ffa95f0c74596bc250dcfd960262841"
-dependencies = [
- "autocfg",
-]
-
 [[package]]
 name = "num_cpus"
 version = "1.16.0"
@@ -515,12 +421,6 @@ version = "1.19.0"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "3fdb12b2476b595f9358c5161aa467c2438859caa136dec86c26fdd2efe17b92"
 
-[[package]]
-name = "oorandom"
-version = "11.1.3"
-source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "0ab1bc2a289d34bd04a330323ac98a1b4bc82c9d9fcb1e66b63caa84da26b575"
-
 [[package]]
 name = "os_pipe"
 version = "1.2.0"
@@ -531,34 +431,6 @@ dependencies = [
  "windows-sys 0.52.0",
 ]
 
-[[package]]
-name = "plotters"
-version = "0.3.6"
-source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "a15b6eccb8484002195a3e44fe65a4ce8e93a625797a063735536fd59cb01cf3"
-dependencies = [
- "num-traits",
- "plotters-backend",
- "plotters-svg",
- "wasm-bindgen",
- "web-sys",
-]
-
-[[package]]
-name = "plotters-backend"
-version = "0.3.6"
-source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "414cec62c6634ae900ea1c56128dfe87cf63e7caece0852ec76aba307cebadb7"
-
-[[package]]
-name = "plotters-svg"
-version = "0.3.6"
-source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "81b30686a7d9c3e010b84284bdd26a29f2138574f52f5eb6f794fc0ad924e705"
-dependencies = [
- "plotters-backend",
-]
-
 [[package]]
 name = "proc-macro2"
 version = "1.0.85"
@@ -577,26 +449,6 @@ dependencies = [
  "proc-macro2",
 ]
 
-[[package]]
-name = "rayon"
-version = "1.10.0"
-source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "b418a60154510ca1a002a752ca9714984e21e4241e804d32555251faf8b78ffa"
-dependencies = [
- "either",
- "rayon-core",
-]
-
-[[package]]
-name = "rayon-core"
-version = "1.12.1"
-source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "1465873a3dfdaa8ae7cb14b4383657caab0b3e8a0aa9ae8e04b044854c8dfce2"
-dependencies = [
- "crossbeam-deque",
- "crossbeam-utils",
-]
-
 [[package]]
 name = "regex"
 version = "1.10.4"
@@ -620,12 +472,32 @@ dependencies = [
  "regex-syntax",
 ]
 
+[[package]]
+name = "regex-lite"
+version = "0.1.6"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "53a49587ad06b26609c52e423de037e7f57f20d53535d66e08c695f347df952a"
+
 [[package]]
 name = "regex-syntax"
 version = "0.8.3"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "adad44e29e4c806119491a7f06f03de4d1af22c3a680dd47f1e6e179439d1f56"
 
+[[package]]
+name = "rustix"
+version = "0.37.27"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "fea8ca367a3a01fe35e6943c400addf443c0f57670e6ec51196f71a4b8762dd2"
+dependencies = [
+ "bitflags",
+ "errno",
+ "io-lifetimes",
+ "libc",
+ "linux-raw-sys",
+ "windows-sys 0.48.0",
+]
+
 [[package]]
 name = "rustversion"
 version = "1.0.17"
@@ -739,6 +611,16 @@ dependencies = [
  "winapi-util",
 ]
 
+[[package]]
+name = "terminal_size"
+version = "0.2.6"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "8e6bf6f19e9f8ed8d4048dc22981458ebcf406d67e94cd422e5ecd73d63b3237"
+dependencies = [
+ "rustix",
+ "windows-sys 0.48.0",
+]
+
 [[package]]
 name = "thread_local"
 version = "1.1.8"
@@ -758,16 +640,6 @@ dependencies = [
  "num_cpus",
 ]
 
-[[package]]
-name = "tinytemplate"
-version = "1.2.1"
-source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "be4d6b5f19ff7664e8c98d03e2139cb510db9b0a60b55f8e8709b689d939b6bc"
-dependencies = [
- "serde",
- "serde_json",
-]
-
 [[package]]
 name = "toml"
 version = "0.5.11"
@@ -831,70 +703,6 @@ dependencies = [
  "winapi-util",
 ]
 
-[[package]]
-name = "wasm-bindgen"
-version = "0.2.92"
-source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "4be2531df63900aeb2bca0daaaddec08491ee64ceecbee5076636a3b026795a8"
-dependencies = [
- "cfg-if",
- "wasm-bindgen-macro",
-]
-
-[[package]]
-name = "wasm-bindgen-backend"
-version = "0.2.92"
-source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "614d787b966d3989fa7bb98a654e369c762374fd3213d212cfc0251257e747da"
-dependencies = [
- "bumpalo",
- "log",
- "once_cell",
- "proc-macro2",
- "quote",
- "syn",
- "wasm-bindgen-shared",
-]
-
-[[package]]
-name = "wasm-bindgen-macro"
-version = "0.2.92"
-source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "a1f8823de937b71b9460c0c34e25f3da88250760bec0ebac694b49997550d726"
-dependencies = [
- "quote",
- "wasm-bindgen-macro-support",
-]
-
-[[package]]
-name = "wasm-bindgen-macro-support"
-version = "0.2.92"
-source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "e94f17b526d0a461a191c78ea52bbce64071ed5c04c9ffe424dcb38f74171bb7"
-dependencies = [
- "proc-macro2",
- "quote",
- "syn",
- "wasm-bindgen-backend",
- "wasm-bindgen-shared",
-]
-
-[[package]]
-name = "wasm-bindgen-shared"
-version = "0.2.92"
-source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "af190c94f2773fdb3729c55b007a722abb5384da03bc0986df4c289bf5567e96"
-
-[[package]]
-name = "web-sys"
-version = "0.3.69"
-source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "77afa9a11836342370f4817622a2f0f418b134426d91a82dfb48f532d2ec13ef"
-dependencies = [
- "js-sys",
- "wasm-bindgen",
-]
-
 [[package]]
 name = "winapi-util"
 version = "0.1.8"
diff --git a/Cargo.toml b/Cargo.toml
index d323686..42ae1b7 100644
--- a/Cargo.toml
+++ b/Cargo.toml
@@ -25,13 +25,14 @@ maintenance = { status = "actively-developed" }
 
 [dependencies]
 anstyle = "1.0.4"
+memchr = { version = "2.7.4", optional = true }
 unicode-width = "0.1.11"
 
 [dev-dependencies]
 annotate-snippets = { path = ".", features = ["testing-colors"] }
 anstream = "0.6.13"
-criterion = "0.5.1"
 difference = "2.0.0"
+divan = "0.1.14"
 glob = "0.3.1"
 serde = { version = "1.0.199", features = ["derive"] }
 snapbox = { version = "0.6.0", features = ["diff", "term-svg", "cmd", "examples"] }
@@ -39,7 +40,7 @@ toml = "0.5.11"
 tryfn = "0.2.1"
 
 [[bench]]
-name = "simple"
+name = "bench"
 harness = false
 
 [[test]]
@@ -48,6 +49,7 @@ harness = false
 
 [features]
 default = []
+simd = ["memchr"]
 testing-colors = []
 
 [lints.rust]
diff --git a/benches/bench.rs b/benches/bench.rs
new file mode 100644
index 0000000..9747954
--- /dev/null
+++ b/benches/bench.rs
@@ -0,0 +1,89 @@
+use annotate_snippets::{Level, Renderer, Snippet};
+
+#[divan::bench]
+fn simple() -> String {
+    let source = r#") -> Option<String> {
+    for ann in annotations {
+        match (ann.range.0, ann.range.1) {
+            (None, None) => continue,
+            (Some(start), Some(end)) if start > end_index => continue,
+            (Some(start), Some(end)) if start >= start_index => {
+                let label = if let Some(ref label) = ann.label {
+                    format!(" {}", label)
+                } else {
+                    String::from("")
+                };
+
+                return Some(format!(
+                    "{}{}{}",
+                    " ".repeat(start - start_index),
+                    "^".repeat(end - start),
+                    label
+                ));
+            }
+            _ => continue,
+        }
+    }"#;
+    let message = Level::Error.title("mismatched types").id("E0308").snippet(
+        Snippet::source(source)
+            .line_start(51)
+            .origin("src/format.rs")
+            .annotation(
+                Level::Warning
+                    .span(5..19)
+                    .label("expected `Option<String>` because of return type"),
+            )
+            .annotation(
+                Level::Error
+                    .span(26..724)
+                    .label("expected enum `std::option::Option`"),
+            ),
+    );
+
+    let renderer = Renderer::plain();
+    let rendered = renderer.render(message).to_string();
+    rendered
+}
+
+#[divan::bench(args=[0, 1, 10, 100, 1_000, 10_000, 100_000])]
+fn fold(bencher: divan::Bencher<'_, '_>, context: usize) {
+    bencher
+        .with_inputs(|| {
+            let line = "012345678901234567890123456789";
+            let mut input = String::new();
+            for _ in 1..=context {
+                input.push_str(line);
+                input.push('\n');
+            }
+            let span_start = input.len() + line.len();
+            let span = span_start..span_start;
+
+            input.push_str(line);
+            input.push('\n');
+            for _ in 1..=context {
+                input.push_str(line);
+                input.push('\n');
+            }
+            (input, span)
+        })
+        .bench_values(|(input, span)| {
+            let message = Level::Error.title("mismatched types").id("E0308").snippet(
+                Snippet::source(&input)
+                    .fold(true)
+                    .origin("src/format.rs")
+                    .annotation(
+                        Level::Warning
+                            .span(span)
+                            .label("expected `Option<String>` because of return type"),
+                    ),
+            );
+
+            let renderer = Renderer::plain();
+            let rendered = renderer.render(message).to_string();
+            rendered
+        });
+}
+
+fn main() {
+    divan::main();
+}
diff --git a/benches/simple.rs b/benches/simple.rs
deleted file mode 100644
index 723793e..0000000
--- a/benches/simple.rs
+++ /dev/null
@@ -1,58 +0,0 @@
-#![allow(clippy::unit_arg)]
-#[macro_use]
-extern crate criterion;
-
-use criterion::{black_box, Criterion};
-
-use annotate_snippets::{Level, Renderer, Snippet};
-
-fn create_snippet(renderer: Renderer) {
-    let source = r#") -> Option<String> {
-    for ann in annotations {
-        match (ann.range.0, ann.range.1) {
-            (None, None) => continue,
-            (Some(start), Some(end)) if start > end_index => continue,
-            (Some(start), Some(end)) if start >= start_index => {
-                let label = if let Some(ref label) = ann.label {
-                    format!(" {}", label)
-                } else {
-                    String::from("")
-                };
-
-                return Some(format!(
-                    "{}{}{}",
-                    " ".repeat(start - start_index),
-                    "^".repeat(end - start),
-                    label
-                ));
-            }
-            _ => continue,
-        }
-    }"#;
-    let message = Level::Error.title("mismatched types").id("E0308").snippet(
-        Snippet::source(source)
-            .line_start(51)
-            .origin("src/format.rs")
-            .annotation(
-                Level::Warning
-                    .span(5..19)
-                    .label("expected `Option<String>` because of return type"),
-            )
-            .annotation(
-                Level::Error
-                    .span(26..724)
-                    .label("expected enum `std::option::Option`"),
-            ),
-    );
-
-    let _result = renderer.render(message).to_string();
-}
-
-pub fn criterion_benchmark(c: &mut Criterion) {
-    c.bench_function("format", |b| {
-        b.iter(|| black_box(create_snippet(Renderer::plain())));
-    });
-}
-
-criterion_group!(benches, criterion_benchmark);
-criterion_main!(benches);
diff --git a/src/renderer/display_list.rs b/src/renderer/display_list.rs
index eea4971..fedf268 100644
--- a/src/renderer/display_list.rs
+++ b/src/renderer/display_list.rs
@@ -1181,7 +1181,7 @@ fn fold_prefix_suffix(mut snippet: snippet::Snippet<'_>) -> snippet::Snippet<'_>
     if let Some(before_new_start) = snippet.source[0..ann_start].rfind('\n') {
         let new_start = before_new_start + 1;
 
-        let line_offset = snippet.source[..new_start].lines().count();
+        let line_offset = newline_count(&snippet.source[..new_start]);
         snippet.line_start += line_offset;
 
         snippet.source = &snippet.source[new_start..];
@@ -1207,6 +1207,17 @@ fn fold_prefix_suffix(mut snippet: snippet::Snippet<'_>) -> snippet::Snippet<'_>
     snippet
 }
 
+fn newline_count(body: &str) -> usize {
+    #[cfg(feature = "simd")]
+    {
+        memchr::memchr_iter(b'\n', body.as_bytes()).count()
+    }
+    #[cfg(not(feature = "simd"))]
+    {
+        body.lines().count()
+    }
+}
+
 fn fold_body(body: Vec<DisplayLine<'_>>) -> Vec<DisplayLine<'_>> {
     const INNER_CONTEXT: usize = 1;
     const INNER_UNFOLD_SIZE: usize = INNER_CONTEXT * 2 + 1;