8334397: RISC-V: verify perf of ReverseBytesS/US

Reviewed-by: fyang, luhenry

src/hotspot/cpu/riscv/riscv.ad

@@ -1916,6 +1916,8 @@ bool Matcher::match_rule_supported(int opcode) {
 
     case Op_ReverseBytesI:
     case Op_ReverseBytesL:
+    case Op_ReverseBytesS:
+    case Op_ReverseBytesUS:
     case Op_RotateRight:
     case Op_RotateLeft:
     case Op_CountLeadingZerosI:
@@ -7866,35 +7868,6 @@ instruct xorL_reg_imm(iRegLNoSp dst, iRegL src1, immLAdd src2) %{
   ins_pipe(ialu_reg_imm);
 %}
 
-// ============================================================================
-// BSWAP Instructions
-
-instruct bytes_reverse_unsigned_short(iRegINoSp dst, iRegIorL2I src) %{
-  match(Set dst (ReverseBytesUS src));
-
-  ins_cost(ALU_COST * 5);
-  format %{ "revb_h_h_u  $dst, $src\t#@bytes_reverse_unsigned_short" %}
-
-  ins_encode %{
-    __ revb_h_h_u(as_Register($dst$$reg), as_Register($src$$reg));
-  %}
-
-  ins_pipe(pipe_class_default);
-%}
-
-instruct bytes_reverse_short(iRegINoSp dst, iRegIorL2I src) %{
-  match(Set dst (ReverseBytesS src));
-
-  ins_cost(ALU_COST * 5);
-  format %{ "revb_h_h  $dst, $src\t#@bytes_reverse_short" %}
-
-  ins_encode %{
-    __ revb_h_h(as_Register($dst$$reg), as_Register($src$$reg));
-  %}
-
-  ins_pipe(pipe_class_default);
-%}
-
 // ============================================================================
 // MemBar Instruction
 

src/hotspot/cpu/riscv/riscv_b.ad

@@ -206,13 +206,13 @@ instruct bytes_reverse_long_b(iRegLNoSp dst, iRegL src) %{
 %}
 
 instruct bytes_reverse_unsigned_short_b(iRegINoSp dst, iRegIorL2I src) %{
-  predicate(UseZbb);
   match(Set dst (ReverseBytesUS src));
 
   ins_cost(ALU_COST * 2);
   format %{ "revb_h_h_u  $dst, $src\t#@bytes_reverse_unsigned_short_b" %}
 
   ins_encode %{
+    assert(UseZbb, "must be");
     __ revb_h_h_u(as_Register($dst$$reg), as_Register($src$$reg));
   %}
 
@@ -220,13 +220,13 @@ instruct bytes_reverse_unsigned_short_b(iRegINoSp dst, iRegIorL2I src) %{
 %}
 
 instruct bytes_reverse_short_b(iRegINoSp dst, iRegIorL2I src) %{
-  predicate(UseZbb);
   match(Set dst (ReverseBytesS src));
 
   ins_cost(ALU_COST * 2);
   format %{ "revb_h_h  $dst, $src\t#@bytes_reverse_short_b" %}
 
   ins_encode %{
+    assert(UseZbb, "must be");
     __ revb_h_h(as_Register($dst$$reg), as_Register($src$$reg));
   %}
 

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

@@ -35,6 +35,7 @@ import org.openjdk.jmh.annotations.Setup;
 import org.openjdk.jmh.annotations.State;
 import org.openjdk.jmh.annotations.Warmup;
 
+import java.util.Random;
 import java.util.concurrent.TimeUnit;
 
 @BenchmarkMode(Mode.AverageTime)
@@ -48,6 +49,29 @@ public class Characters {
     @Param({"9", "65", "97", "223", "430"})
     private int codePoint;
 
+    @Param("500")
+    private int size;
+
+    private char[] chars;
+    private char[] res;
+
+    @Setup
+    public void setup() {
+        Random r  = new Random(0);
+        chars     = new char[size];
+        res       = new char[size];
+        for (int i = 0; i < size; i++) {
+            chars[i] = (char)r.nextInt(Character.MAX_VALUE + 1);
+        }
+    }
+
+    @Benchmark
+    public void reverseBytes() {
+        for (int i = 0; i < size; i++) {
+            res[i] = Character.reverseBytes(chars[i]);
+        }
+    }
+
     @Benchmark
     public boolean isDigit() {
         return Character.isDigit(codePoint);

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

@@ -0,0 +1,70 @@
+/*
+ * Copyright (c) 2024, 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.Benchmark;
+import org.openjdk.jmh.annotations.BenchmarkMode;
+import org.openjdk.jmh.annotations.Fork;
+import org.openjdk.jmh.annotations.Measurement;
+import org.openjdk.jmh.annotations.Mode;
+import org.openjdk.jmh.annotations.OutputTimeUnit;
+import org.openjdk.jmh.annotations.Param;
+import org.openjdk.jmh.annotations.Scope;
+import org.openjdk.jmh.annotations.Setup;
+import org.openjdk.jmh.annotations.State;
+import org.openjdk.jmh.annotations.Warmup;
+
+import java.util.Random;
+import java.util.concurrent.TimeUnit;
+
+@BenchmarkMode(Mode.AverageTime)
+@OutputTimeUnit(TimeUnit.NANOSECONDS)
+@State(Scope.Thread)
+@Warmup(iterations = 5, time = 1)
+@Measurement(iterations = 5, time = 1)
+@Fork(3)
+public class Shorts {
+
+    @Param("500")
+    private int size;
+
+    private short[] shorts;
+    private short[] res;
+
+    @Setup
+    public void setup() {
+        Random r  = new Random(0);
+        shorts     = new short[size];
+        res       = new short[size];
+        for (int i = 0; i < size; i++) {
+            shorts[i] = (short)(r.nextInt(Character.MAX_VALUE + 1) + Short.MIN_VALUE);
+        }
+    }
+
+    @Benchmark
+    public void reverseBytes() {
+        for (int i = 0; i < size; i++) {
+            res[i] = Short.reverseBytes(shorts[i]);
+        }
+    }
+}