@@ -32,9 +32,13 @@ Unreleased
 - A performance improvement in the low-level line number bookkeeping when
   combining data files, thanks to `Kevin Turcios <pull 2239_>`_.
 
+- Performance improvement in HTML reporting by reducing the number of times
+  files have to be parsed, thanks to `Kevin Turcios <pull 2240_>`_.
+
 .. _issue 2200: https://github.com/coveragepy/coveragepy/issues/2200
 .. _pull 2234: https://github.com/coveragepy/coveragepy/pull/2234
 .. _pull 2239: https://github.com/coveragepy/coveragepy/pull/2239
+.. _pull 2240: https://github.com/coveragepy/coveragepy/pull/2240
 
 
 .. start-releases
 
@@ -92,6 +92,13 @@ def _phys_tokens(toks: TokenInfos) -> TokenInfos:
 
 def find_soft_key_lines(source: str) -> set[TLineNo]:
     """Helper for finding lines with soft keywords, like match/case lines."""
+    # Do a quick check first, to eliminate files with no possibility of soft keywords.
+    # match/case is only a soft keyword if both words are in the source.
+    if "match" not in source or "case" not in source:
+        if sys.version_info < (3, 12) or "type" not in source:
+            if sys.version_info < (3, 15) or "lazy" not in source:
+                return set()
+
     soft_key_lines: set[TLineNo] = set()
 
     for node in ast.walk(ast.parse(source)):