8277882: New subnode ideal optimization: converting "c0 - (x + c1)" into "(c0 - c1) - x"

src/hotspot/share/opto/subnode.cpp

@@ -196,16 +196,23 @@ Node *SubINode::Ideal(PhaseGVN *phase, bool can_reshape){
     }
   }
 
-
-  // Convert "x - (y+c0)" into "(x-y) - c0"
+  // Convert "x - (y+c0)" into "(x-y) - c0" AND
+  // Convert "c1 - (y+c0)" into "(c1-c0) - y"
   // Need the same check as in above optimization but reversed.
-  if (op2 == Op_AddI && ok_to_convert(in2, in1)) {
+  if (op2 == Op_AddI
+      && ok_to_convert(in2, in1)
+      && in2->in(2)->Opcode() == Op_ConI) {
+    jint c0 = phase->type(in2->in(2))->isa_int()->get_con();
     Node* in21 = in2->in(1);
-    Node* in22 = in2->in(2);
-    const TypeInt* tcon = phase->type(in22)->isa_int();
-    if (tcon != NULL && tcon->is_con()) {
-      Node* sub2 = phase->transform( new SubINode(in1, in21) );
-      Node* neg_c0 = phase->intcon(- tcon->get_con());
+    if (in1->Opcode() == Op_ConI) {
+      // Match c1
+      jint c1 = phase->type(in1)->isa_int()->get_con();
+      Node* sub2 = phase->intcon(java_subtract(c1, c0));
+      return new SubINode(sub2, in21);
+    } else {
+      // Match x
+      Node* sub2 = phase->transform(new SubINode(in1, in21));
+      Node* neg_c0 = phase->intcon(-c0);
       return new AddINode(sub2, neg_c0);
     }
   }
@@ -374,15 +381,22 @@ Node *SubLNode::Ideal(PhaseGVN *phase, bool can_reshape) {
     }
   }
 
-  // Convert "x - (y+c0)" into "(x-y) - c0"
+  // Convert "x - (y+c0)" into "(x-y) - c0" AND
+  // Convert "c1 - (y+c0)" into "(c1-c0) - y"
   // Need the same check as in above optimization but reversed.
-  if (op2 == Op_AddL && ok_to_convert(in2, in1)) {
+  if (op2 == Op_AddL
+      && ok_to_convert(in2, in1)
+      && in2->in(2)->Opcode() == Op_ConL) {
+    jlong c0 = phase->type(in2->in(2))->isa_long()->get_con();
     Node* in21 = in2->in(1);
-    Node* in22 = in2->in(2);
-    const TypeLong* tcon = phase->type(in22)->isa_long();
-    if (tcon != NULL && tcon->is_con()) {
-      Node* sub2 = phase->transform( new SubLNode(in1, in21) );
-      Node* neg_c0 = phase->longcon(- tcon->get_con());
+    if (in1->Opcode() == Op_ConL) {
+      // Match c1
+      jlong c1 = phase->type(in1)->isa_long()->get_con();
+      Node* sub2 = phase->longcon(java_subtract(c1, c0));
+      return new SubLNode(sub2, in21);
+    } else {
+      Node* sub2 = phase->transform(new SubLNode(in1, in21));
+      Node* neg_c0 = phase->longcon(-c0);
       return new AddLNode(sub2, neg_c0);
     }
   }

test/hotspot/jtreg/compiler/c2/TestSubIdealC0Minus_YPlusC1_.java

@@ -0,0 +1,133 @@
+/*
+ * Copyright (c) 2021, 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.
+ */
+
+/*
+ * @test
+ * @bug 8277882
+ * @summary New subnode ideal optimization: converting "c0 - (x + c1)" into "(c0 - c1) - x"
+ * @library /test/lib
+ * @run main/othervm -XX:-TieredCompilation -Xbatch
+ *                   -XX:CompileCommand=dontinline,compiler.c2.TestSubIdealC0Minus_YPlusC1_::test*
+ *                   -XX:CompileCommand=compileonly,compiler.c2.TestSubIdealC0Minus_YPlusC1_::test*
+ *                   compiler.c2.TestSubIdealC0Minus_YPlusC1_
+ */
+package compiler.c2;
+
+import jdk.test.lib.Asserts;
+
+public class TestSubIdealC0Minus_YPlusC1_ {
+
+    private static final int I_C0_0 = 1234;
+    private static final int I_C1 = 1234;
+    private static final int I_C0_1 = 4321;
+
+    private static final long L_C0_0 = 123_456_789_123L;
+    private static final long L_C1 = 123_456_789_123L;
+    private static final long L_C0_1 = 654_321;
+
+    public static int testIC0EqualsC1(int x) {
+        return I_C0_0 - (x + I_C1);
+    }
+
+    public static long testLC0EqualsC1(long x) {
+        return L_C0_0 - (x + L_C1);
+    }
+
+    public static int testIC0NotEqualsC1(int x) {
+        return I_C0_1 - (x + I_C1);
+    }
+
+    public static long testLC0NotEqualsC1(long x) {
+        return L_C0_1 - (x + L_C1);
+    }
+
+    public static int testIXPlusC1IsOverflow(int x) {
+        return Integer.MAX_VALUE - (x + Integer.MAX_VALUE);
+    }
+
+    public static long testLXPlusC1IsOverflow(long x) {
+        return Long.MAX_VALUE - (x + Long.MAX_VALUE);
+    }
+
+    public static int testIXPlusC1IsUnderflow(int x) {
+        return Integer.MIN_VALUE - (x + Integer.MIN_VALUE);
+    }
+
+    public static long testLXPlusC1IsUnderflow(long x) {
+        return Long.MIN_VALUE - (x + Long.MIN_VALUE);
+    }
+
+    public static int testIC0MinusC1IsOverflow(int x) {
+        return Integer.MAX_VALUE - (x + Integer.MIN_VALUE);
+    }
+
+    public static long testLC0MinusC1IsOverflow(long x) {
+        return Long.MAX_VALUE - (x + Long.MIN_VALUE);
+    }
+
+    public static int testIC0MinusC1IsUnderflow(int x) {
+        return Integer.MIN_VALUE - (x + Integer.MAX_VALUE);
+    }
+
+    public static long testLC0MinusC1IsUnderflow(long x) {
+        return Long.MIN_VALUE - (x + Long.MAX_VALUE);
+    }
+
+    public static int testIResultIsOverflow(int x) {
+        return 2147483637 - (x + 10); // Integer.MAX_VALUE == 2147483647
+    }
+
+    public static long testLResultIsOverflow(long x) {
+        return 9223372036854775797L - (x + 10); // Long.MAX_VALUE == 9223372036854775807
+    }
+
+    public static int testIResultIsUnderflow(int x) {
+        return -2147483637 - (x + 10); // Integer.MIN_VALUE == -2147483648
+    }
+
+    public static long testLResultIsUnderflow(long x) {
+        return -9223372036854775797L - (x + 10); // Long.MIN_VALUE == -9223372036854775808
+    }
+
+    public static void main(String... args) {
+        for (int i = 0; i < 50_000; i++) {
+            Asserts.assertTrue(testIC0EqualsC1(10) == -10);
+            Asserts.assertTrue(testIC0NotEqualsC1(100) == 2987);
+            Asserts.assertTrue(testIXPlusC1IsOverflow(10) == -10);
+            Asserts.assertTrue(testIXPlusC1IsUnderflow(-10) == 10);
+            Asserts.assertTrue(testIC0MinusC1IsOverflow(10) == -11);
+            Asserts.assertTrue(testIC0MinusC1IsUnderflow(10) == -9);
+            Asserts.assertTrue(testIResultIsOverflow(-21) == Integer.MIN_VALUE);
+            Asserts.assertTrue(testIResultIsUnderflow(2) == Integer.MAX_VALUE);
+
+            Asserts.assertTrue(testLC0EqualsC1(10) == -10);
+            Asserts.assertTrue(testLC0NotEqualsC1(100) == -123456134902L);
+            Asserts.assertTrue(testLXPlusC1IsOverflow(10) == -10);
+            Asserts.assertTrue(testLXPlusC1IsUnderflow(-10) == 10);
+            Asserts.assertTrue(testLC0MinusC1IsOverflow(10) == -11);
+            Asserts.assertTrue(testLC0MinusC1IsUnderflow(10) == -9);
+            Asserts.assertTrue(testLResultIsOverflow(-21) == Long.MIN_VALUE);
+            Asserts.assertTrue(testLResultIsUnderflow(2) == Long.MAX_VALUE);
+        }
+    }
+}

test/micro/org/openjdk/bench/vm/compiler/SubIdealC0Minus_YPlusC1_.java

@@ -0,0 +1,110 @@
+/*
+ * Copyright (c) 2021, 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.vm.compiler;
+
+import org.openjdk.jmh.annotations.Benchmark;
+import org.openjdk.jmh.annotations.BenchmarkMode;
+import org.openjdk.jmh.annotations.CompilerControl;
+import org.openjdk.jmh.annotations.Fork;
+import org.openjdk.jmh.annotations.Measurement;
+import org.openjdk.jmh.annotations.Mode;
+import org.openjdk.jmh.annotations.Scope;
+import org.openjdk.jmh.annotations.Setup;
+import org.openjdk.jmh.annotations.State;
+import org.openjdk.jmh.annotations.OutputTimeUnit;
+import org.openjdk.jmh.annotations.Warmup;
+import org.openjdk.jmh.infra.Blackhole;
+
+import java.util.concurrent.TimeUnit;
+
+/**
+ * Tests transformation that converts "c0 - (x + c1)" into "(c0 - c1)
+ * - x" in SubINode::Ideal and SubLNode::Ideal.
+ */
+@BenchmarkMode(Mode.AverageTime)
+@OutputTimeUnit(TimeUnit.MILLISECONDS)
+@State(Scope.Thread)
+@Warmup(iterations = 5, time = 1, timeUnit = TimeUnit.SECONDS)
+@Measurement(iterations = 5, time = 1, timeUnit = TimeUnit.SECONDS)
+@Fork(value = 3 , jvmArgsAppend = {"-XX:-TieredCompilation", "-Xbatch", "-Xcomp"})
+public class SubIdealC0Minus_YPlusC1_ {
+
+    private static final int I_C0 = 1234567;
+
+    private static final int I_C1 = 1234567;
+
+    private static final long L_C0 = 123_456_789_123_456L;
+
+    private static final long L_C1 = 123_456_789_123_456L;
+
+    private final int size = 100_000_000;
+
+    private int[] ints_a;
+
+    private long[] longs_a;
+
+    @Setup
+    public void init() {
+        ints_a = new int[size];
+        longs_a = new long[size];
+        for (int i = 0; i < size; i++) {
+            ints_a[i] = i;
+            longs_a[i] = i * i;
+        }
+    }
+
+    @Benchmark
+    public void baseline() {
+        for (int i = 0; i < size; i++) {
+            sink(ints_a[i]);
+            sink(longs_a[i]);
+        }
+    }
+
+    @Benchmark
+    public void test() {
+        for (int i = 0; i < size; i++) {
+            sink(helper(ints_a[i]));
+            sink(helper(longs_a[i]));
+        }
+    }
+
+    // Convert "c0 - (x + c1)" into "(c0 - c1) - x" for int.
+    @CompilerControl(CompilerControl.Mode.DONT_INLINE)
+    private static int helper(int x) {
+        return I_C0 - (x + I_C1);
+    }
+
+    // Convert "c0 - (x + c1)" into "(c0 - c1) - x" for long.
+    @CompilerControl(CompilerControl.Mode.DONT_INLINE)
+    private static long helper(long x) {
+        return L_C0 - (x + L_C1);
+    }
+
+    @CompilerControl(CompilerControl.Mode.DONT_INLINE)
+    private static void sink(int v) {}
+
+    @CompilerControl(CompilerControl.Mode.DONT_INLINE)
+    private static void sink(long v) {}
+}