8222955: Optimize String.replace(CharSequence, CharSequence) for common cases

Reviewed-by: redestad, tvaleev

test/micro/org/openjdk/bench/java/lang/StringReplace.java

@@ -0,0 +1,106 @@
+/*
+ * Copyright (c) 2019, Oracle and/or its affiliates. All rights reserved.
+ * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
+ *
+ * This code is free software; you can redistribute it and/or modify it
+ * under the terms of the GNU General Public License version 2 only, as
+ * published by the Free Software Foundation.
+ *
+ * This code is distributed in the hope that it will be useful, but WITHOUT
+ * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
+ * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
+ * version 2 for more details (a copy is included in the LICENSE file that
+ * accompanied this code).
+ *
+ * You should have received a copy of the GNU General Public License version
+ * 2 along with this work; if not, write to the Free Software Foundation,
+ * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
+ *
+ * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
+ * or visit www.oracle.com if you need additional information or have any
+ * questions.
+ */
+
+package org.openjdk.bench.java.lang;
+
+import org.openjdk.jmh.annotations.*;
+import java.util.concurrent.TimeUnit;
+
+@BenchmarkMode(Mode.AverageTime)
+@OutputTimeUnit(TimeUnit.NANOSECONDS)
+@State(Scope.Benchmark)
+public class StringReplace {
+
+    public String slat1 = new String("java.lang.String");
+    public String sutf16 = new String("\u1D36\u1D43\u1D5B\u1D43 \uFF11\uFF13");
+
+    @Benchmark
+    public String replace0x1_1_Latin1() {
+        return slat1.replace("Z", "z");
+    }
+
+    @Benchmark
+    public String replace1x1_0_Latin1() {
+        return slat1.replace("g", "");
+    }
+
+    @Benchmark
+    public String replace1x1_1_Latin1() {
+        return slat1.replace("g", "k");
+    }
+
+    @Benchmark
+    public String replace1x1_2_Latin1() {
+        return slat1.replace("g", "th");
+    }
+
+    @Benchmark
+    public String replace2x1_0_Latin1() {
+        return slat1.replace(".", "");
+    }
+
+    @Benchmark
+    public String replace2x1_1_Latin1() {
+        return slat1.replace(".", "/");
+    }
+
+    @Benchmark
+    public String replace2x1_2_Latin1() {
+        return slat1.replace(".", "::");
+    }
+
+    @Benchmark
+    public String replace0x1_1_UTF16() {
+        return sutf16.replace("\u1D36", "\u1D38\u1D3A");
+    }
+
+    @Benchmark
+    public String replace1x1_0_UTF16() {
+        return sutf16.replace("\uFF11", "");
+    }
+
+    @Benchmark
+    public String replace1x1_1_UTF16() {
+        return sutf16.replace("\u1D36", "\u24BF");
+    }
+
+    @Benchmark
+    public String replace1x1_2_UTF16() {
+        return sutf16.replace("\uFF11", "\uFF11\uFF12");
+    }
+
+    @Benchmark
+    public String replace2x1_0_UTF16() {
+        return sutf16.replace("\u1D43", "");
+    }
+
+    @Benchmark
+    public String replace2x1_1_UTF16() {
+        return sutf16.replace("\u1D43", "\u1D2C");
+    }
+
+    @Benchmark
+    public String replace2x1_2_UTF16() {
+        return sutf16.replace("\u1D43", "\u21DB\u21DB");
+    }
+}