Add ExactMathBenchmark.

Author: woess

truffle/src/org.graalvm.truffle.benchmark/src/org/graalvm/truffle/benchmark/ExactMathBenchmark.java

@@ -0,0 +1,197 @@
+/*
+ * Copyright (c) 2025, Oracle and/or its affiliates. All rights reserved.
+ * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
+ *
+ * The Universal Permissive License (UPL), Version 1.0
+ *
+ * Subject to the condition set forth below, permission is hereby granted to any
+ * person obtaining a copy of this software, associated documentation and/or
+ * data (collectively the "Software"), free of charge and under any and all
+ * copyright rights in the Software, and any and all patent rights owned or
+ * freely licensable by each licensor hereunder covering either (i) the
+ * unmodified Software as contributed to or provided by such licensor, or (ii)
+ * the Larger Works (as defined below), to deal in both
+ *
+ * (a) the Software, and
+ *
+ * (b) any piece of software and/or hardware listed in the lrgrwrks.txt file if
+ * one is included with the Software each a "Larger Work" to which the Software
+ * is contributed by such licensors),
+ *
+ * without restriction, including without limitation the rights to copy, create
+ * derivative works of, display, perform, and distribute the Software and make,
+ * use, sell, offer for sale, import, export, have made, and have sold the
+ * Software and the Larger Work(s), and to sublicense the foregoing rights on
+ * either these or other terms.
+ *
+ * This license is subject to the following condition:
+ *
+ * The above copyright notice and either this complete permission notice or at a
+ * minimum a reference to the UPL must be included in all copies or substantial
+ * portions of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+ * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+ * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+ * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
+ * SOFTWARE.
+ */
+package org.graalvm.truffle.benchmark;
+
+import java.util.Random;
+import java.util.stream.DoubleStream;
+
+import org.openjdk.jmh.annotations.Benchmark;
+import org.openjdk.jmh.annotations.Fork;
+import org.openjdk.jmh.annotations.Measurement;
+import org.openjdk.jmh.annotations.Scope;
+import org.openjdk.jmh.annotations.State;
+import org.openjdk.jmh.annotations.Warmup;
+import org.openjdk.jmh.infra.Blackhole;
+
+import com.oracle.truffle.api.CompilerDirectives;
+import com.oracle.truffle.api.ExactMath;
+
+/**
+ * Benchmarks {@link ExactMath} functions.
+ *
+ * Checkstyle: stop
+ */
+@Warmup(iterations = 5, time = TruffleBenchmark.Defaults.ITERATION_TIME)
+@Measurement(iterations = 5, time = TruffleBenchmark.Defaults.ITERATION_TIME)
+@Fork(TruffleBenchmark.Defaults.FORKS)
+public class ExactMathBenchmark extends TruffleBenchmark {
+
+    @State(Scope.Benchmark)
+    public static class ThreadState {
+        // fixed random seed for reproducibility
+        private static final int RANDOM_SEED = 42;
+        private static final int LENGTH = 10_000;
+
+        Random r = new Random(RANDOM_SEED);
+        long[] longs = r.longs(LENGTH).toArray();
+        double[] doubles = DoubleStream.concat(
+                        DoubleStream.of(Double.NaN, Double.POSITIVE_INFINITY, Double.NEGATIVE_INFINITY, -0.0, 0.0),
+                        r.doubles(LENGTH, -0x1p10, 0x1p+65)).toArray();
+
+        double[] doublesValidUI64 = r.doubles(LENGTH, Math.nextUp(-1.0), 0x1p64).toArray();
+        double[] doublesValidSI64 = r.doubles(LENGTH, -0x1p63, 0x1p63).toArray();
+    }
+
+    /**
+     * Signed version as a performance reference point for unsigned.
+     */
+    @Benchmark
+    public void doubleToSignedLongSat(ThreadState state, Blackhole blackhole) {
+        for (double input : state.doubles) {
+            blackhole.consume((long) input);
+        }
+    }
+
+    @Benchmark
+    public void doubleToUnsignedLongSat(ThreadState state, Blackhole blackhole) {
+        for (double input : state.doubles) {
+            blackhole.consume(ExactMath.truncateToUnsignedLong(input));
+        }
+    }
+
+    @Benchmark
+    public void doubleToUnsignedLongSatFallback(ThreadState state, Blackhole blackhole) {
+        for (double input : state.doubles) {
+            blackhole.consume(truncateToUnsignedLongFallback(input));
+        }
+    }
+
+    /**
+     * Signed version as a performance reference point for unsigned.
+     */
+    @Benchmark
+    public void doubleToSignedLongChecked(ThreadState state, Blackhole blackhole) {
+        for (double input : state.doublesValidSI64) {
+            blackhole.consume(i64_trunc_f64_s(input));
+        }
+    }
+
+    @Benchmark
+    public void doubleToUnsignedLongChecked(ThreadState state, Blackhole blackhole) {
+        for (double input : state.doublesValidUI64) {
+            blackhole.consume(i64_trunc_f64_u(input));
+        }
+    }
+
+    /**
+     * Signed version as a performance reference point for unsigned.
+     */
+    @Benchmark
+    public void longToDoubleSigned(ThreadState state, Blackhole blackhole) {
+        for (long input : state.longs) {
+            blackhole.consume((double) input);
+        }
+    }
+
+    @Benchmark
+    public void longToDoubleUnsigned(ThreadState state, Blackhole blackhole) {
+        for (long input : state.longs) {
+            blackhole.consume(ExactMath.unsignedToDouble(input));
+        }
+    }
+
+    @Benchmark
+    public void longToDoubleUnsignedFallback(ThreadState state, Blackhole blackhole) {
+        for (long input : state.longs) {
+            blackhole.consume(unsignedToDoubleFallback(input));
+        }
+    }
+
+    /**
+     * @see ExactMath#unsignedToDouble(long)
+     */
+    public static double unsignedToDoubleFallback(long x) {
+        if (x >= 0) {
+            return x;
+        } else {
+            double halfRoundUp = ((x >>> 1) | (x & 1));
+            return halfRoundUp + halfRoundUp;
+        }
+    }
+
+    /**
+     * @see ExactMath#truncateToUnsignedLong(double)
+     */
+    private static long truncateToUnsignedLongFallback(double x) {
+        if (x >= 0x1p63) {
+            long signedResult = (long) (x - 0x1p63);
+            return signedResult | (1L << 63);
+        } else {
+            long signedResult = (long) x;
+            return signedResult & ~(signedResult >> 63); // max(result, 0)
+        }
+    }
+
+    private long i64_trunc_f64_u(double x) {
+        if (x > -1.0 && x < 0x1p64) {
+            return ExactMath.truncateToUnsignedLong(x);
+        } else {
+            return truncError(x);
+        }
+    }
+
+    private long i64_trunc_f64_s(double x) {
+        if (x >= -0x1p63 && x < 0x1p63) {
+            return (long) x;
+        } else {
+            return truncError(x);
+        }
+    }
+
+    private static long truncError(double x) {
+        CompilerDirectives.transferToInterpreterAndInvalidate();
+        if (Double.isNaN(x)) {
+            throw new AssertionError(x);
+        } else {
+            throw new AssertionError(x);
+        }
+    }
+}