diff --git a/pkg/compiler/lib/src/ssa/logging.dart b/pkg/compiler/lib/src/ssa/logging.dart
index e2c63af..77c888e 100644
--- a/pkg/compiler/lib/src/ssa/logging.dart
+++ b/pkg/compiler/lib/src/ssa/logging.dart
@@ -232,18 +232,15 @@
   }
 
   void registerSubstring(HInvokeDynamic original) {
-    Features features = new Features();
-    entries.add(new OptimizationLogEntry('Substring', features));
+    _registerSpecializer(original, null, null, 'substring');
   }
 
   void registerTrim(HInvokeDynamic original) {
-    Features features = new Features();
-    entries.add(new OptimizationLogEntry('Trim', features));
+    _registerSpecializer(original, null, null, 'trim');
   }
 
   void registerPatternMatch(HInvokeDynamic original) {
-    Features features = new Features();
-    entries.add(new OptimizationLogEntry('PatternMatch', features));
+    _registerSpecializer(original, null, null, original.selector.name);
   }
 
   void registerRound(HInvokeDynamic original) {
diff --git a/pkg/compiler/test/optimization/data/string_methods.dart b/pkg/compiler/test/optimization/data/string_methods.dart
new file mode 100644
index 0000000..c2aabfc
--- /dev/null
+++ b/pkg/compiler/test/optimization/data/string_methods.dart
@@ -0,0 +1,163 @@
+// Copyright (c) 2021, the Dart project authors.  Please see the AUTHORS file
+// for details. All rights reserved. Use of this source code is governed by a
+// BSD-style license that can be found in the LICENSE file.
+
+// ---- String.substring
+
+/*member: substring1:Specializer=[substring]*/
+@pragma('dart2js:noInline')
+substring1(String param) {
+  return param.substring(1);
+}
+
+/*member: substring2:Specializer=[substring]*/
+@pragma('dart2js:noInline')
+substring2(String param) {
+  return param.substring(1, 3);
+}
+
+/*member: substring3:Specializer=[substring]*/
+@pragma('dart2js:noInline')
+substring3(String param) {
+  dynamic s = param;
+  return s.substring(1, 2); // Not confused by static type.
+}
+
+/*member: substring4:*/
+@pragma('dart2js:noInline')
+substring4(String param) {
+  dynamic s = param;
+  return s.substring(1, 2, 3); // Arity mismatch.
+}
+
+/*member: substring5:*/
+@pragma('dart2js:noInline')
+substring5(String param) {
+  dynamic s = [param];
+  return s.substring(1); // Receiver mismatch.
+}
+
+// ---- String.trim
+
+/*member: trim1:Specializer=[trim]*/
+@pragma('dart2js:noInline')
+trim1(String param) {
+  return param.trim();
+}
+
+// ---- String.indexOf
+
+/*member: indexOf1:Specializer=[indexOf]*/
+@pragma('dart2js:noInline')
+indexOf1(String param) {
+  return param.indexOf('e');
+}
+
+/*member: indexOf2:Specializer=[indexOf]*/
+@pragma('dart2js:noInline')
+indexOf2(String param) {
+  return param.indexOf('e', 3);
+}
+
+// Specializer does not match as the pattern is not a string.
+/*member: indexOf3:*/
+@pragma('dart2js:noInline')
+indexOf3(String param) {
+  return param.indexOf(RegExp('e'));
+}
+
+// ---- String.contains
+
+/*member: contains1:Specializer=[contains]*/
+@pragma('dart2js:noInline')
+contains1(String param) {
+  return param.contains('e');
+}
+
+/*member: contains2:Specializer=[contains]*/
+@pragma('dart2js:noInline')
+contains2(String param) {
+  return param.contains('e', 3);
+}
+
+// Specializer does not match as the pattern is not a string.
+/*member: contains3:*/
+@pragma('dart2js:noInline')
+contains3(String param) {
+  return param.contains(RegExp('e'));
+}
+
+// ---- String.startsWith
+
+/*member: startsWith1:Specializer=[startsWith]*/
+@pragma('dart2js:noInline')
+startsWith1(String param) {
+  return param.startsWith('e');
+}
+
+/*member: startsWith2:Specializer=[startsWith]*/
+@pragma('dart2js:noInline')
+startsWith2(String param) {
+  return param.startsWith('e', 3);
+}
+
+// Specializer does not match as the pattern is not a string.
+/*member: startsWith3:*/
+@pragma('dart2js:noInline')
+startsWith3(String param) {
+  return param.startsWith(RegExp('e'));
+}
+
+// ---- String.endsWith
+
+/*member: endsWith1:Specializer=[endsWith]*/
+@pragma('dart2js:noInline')
+endsWith1(String param) {
+  return param.endsWith('e');
+}
+
+main() {
+  substring1('hello');
+  substring1('bye');
+  substring1('');
+  substring2('hello');
+  substring2('bye');
+  substring2('');
+  substring3('hello');
+  substring3('bye');
+  substring3('');
+  substring4('hello');
+  substring4('bye');
+  substring4('');
+  substring5('hello');
+  substring5('bye');
+  substring5('');
+
+  trim1('hello');
+  trim1(' bye ');
+  trim1('    ');
+
+  indexOf1('hello');
+  indexOf1('bye');
+  indexOf2('hello');
+  indexOf2('bye');
+  indexOf3('hello');
+  indexOf3('bye');
+
+  contains1('hello');
+  contains1('bye');
+  contains2('hello');
+  contains2('bye');
+  contains3('hello');
+  contains3('bye');
+
+  startsWith1('hello');
+  startsWith1('bye');
+  startsWith2('hello');
+  startsWith2('bye');
+  startsWith3('hello');
+  startsWith3('bye');
+
+  endsWith1('hello');
+  endsWith1('bye');
+}