diff --git a/library/core/src/unicode/unicode_data.rs b/library/core/src/unicode/unicode_data.rs
index 56f5b7ed8eb1..f25f443567a8 100644
--- a/library/core/src/unicode/unicode_data.rs
+++ b/library/core/src/unicode/unicode_data.rs
@@ -433,6 +433,8 @@ pub mod grapheme_extend {
     pub fn lookup(c: char) -> bool {
         (c as u32) >= 0x300 && lookup_slow(c)
     }
+
+    #[inline(never)]
     fn lookup_slow(c: char) -> bool {
         const {
             assert!(SHORT_OFFSET_RUNS.last().unwrap().0 > (char::MAX as u32));
diff --git a/src/tools/unicode-table-generator/src/skiplist.rs b/src/tools/unicode-table-generator/src/skiplist.rs
index c2e44aec8903..e4c3d96546f1 100644
--- a/src/tools/unicode-table-generator/src/skiplist.rs
+++ b/src/tools/unicode-table-generator/src/skiplist.rs
@@ -105,6 +105,8 @@ impl RawEmitter {
             writeln!(&mut self.file, "    (c as u32) >= {first_code_point:#04x} && lookup_slow(c)")
                 .unwrap();
             writeln!(&mut self.file, "}}").unwrap();
+            writeln!(&mut self.file).unwrap();
+            writeln!(&mut self.file, "#[inline(never)]").unwrap();
             writeln!(&mut self.file, "fn lookup_slow(c: char) -> bool {{").unwrap();
         } else {
             writeln!(&mut self.file, "pub fn lookup(c: char) -> bool {{").unwrap();