8276673: Optimize abs operations in C2 compiler

src/hotspot/share/opto/subnode.cpp

@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 1997, 2021, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 1997, 2022, 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
@@ -1847,6 +1847,64 @@ bool BoolNode::is_counted_loop_exit_test() {
   return false;
 }
 
+//=============================================================================
+//------------------------------Value------------------------------------------
+const Type* AbsNode::Value(PhaseGVN* phase) const {
+  const Type* t1 = phase->type(in(1));
+  if (t1 == Type::TOP) return Type::TOP;
+
+  switch (t1->base()) {
+  case Type::Int: {
+    const TypeInt* ti = t1->is_int();
+    if (ti->is_con()) {
+      return TypeInt::make(uabs(ti->get_con()));
+    }
+    break;
+  }
+  case Type::Long: {
+    const TypeLong* tl = t1->is_long();
+    if (tl->is_con()) {
+      return TypeLong::make(uabs(tl->get_con()));
+    }
+    break;
+  }
+  case Type::FloatCon:
+    return TypeF::make(abs(t1->getf()));
+  case Type::DoubleCon:
+    return TypeD::make(abs(t1->getd()));
+  default:
+    break;
+  }
+
+  return bottom_type();
+}
+
+//------------------------------Identity----------------------------------------
+Node* AbsNode::Identity(PhaseGVN* phase) {
+  Node* in1 = in(1);
+  // No need to do abs for non-negative values
+  if (phase->type(in1)->higher_equal(TypeInt::POS) ||
+      phase->type(in1)->higher_equal(TypeLong::POS)) {
+    return in1;
+  }
+  // Convert "abs(abs(x))" into "abs(x)"
+  if (in1->Opcode() == Opcode()) {
+    return in1;
+  }
+  return this;
+}
+
+//------------------------------Ideal------------------------------------------
+Node* AbsNode::Ideal(PhaseGVN* phase, bool can_reshape) {
+  Node* in1 = in(1);
+  // Convert "abs(0-x)" into "abs(x)"
+  if (in1->is_Sub() && phase->type(in1->in(1))->is_zero_type()) {
+    set_req_X(1, in1->in(2), phase);
+    return this;
+  }
+  return NULL;
+}
+
 //=============================================================================
 //------------------------------Value------------------------------------------
 // Compute sqrt

src/hotspot/share/opto/subnode.hpp

@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 1997, 2019, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 1997, 2022, 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
@@ -347,6 +347,9 @@ class BoolNode : public Node {
 class AbsNode : public Node {
 public:
   AbsNode( Node *value ) : Node(0,value) {}
+  virtual Node* Identity(PhaseGVN* phase);
+  virtual Node* Ideal(PhaseGVN* phase, bool can_reshape);
+  virtual const Type* Value(PhaseGVN* phase) const;
 };
 
 //------------------------------AbsINode---------------------------------------

src/hotspot/share/opto/type.hpp

@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 1997, 2021, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 1997, 2022, 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
@@ -593,7 +593,7 @@ class TypeInt : public TypeInteger {
 
   // Check for single integer
   bool is_con() const { return _lo==_hi; }
-  bool is_con(int i) const { return is_con() && _lo == i; }
+  bool is_con(jint i) const { return is_con() && _lo == i; }
   jint get_con() const { assert(is_con(), "" );  return _lo; }
 
   virtual bool        is_finite() const;  // Has a finite value
@@ -661,7 +661,7 @@ class TypeLong : public TypeInteger {
 
   // Check for single integer
   bool is_con() const { return _lo==_hi; }
-  bool is_con(int i) const { return is_con() && _lo == i; }
+  bool is_con(jlong i) const { return is_con() && _lo == i; }
   jlong get_con() const { assert(is_con(), "" ); return _lo; }
 
   // Check for positive 32-bit value.

test/hotspot/jtreg/compiler/c2/irTests/TestIRAbs.java

@@ -0,0 +1,231 @@
+/*
+ * Copyright (c) 2022, Arm Limited. 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 compiler.c2.irTests;
+
+import jdk.test.lib.Asserts;
+import compiler.lib.ir_framework.*;
+
+/*
+ * @test
+ * @bug 8276673
+ * @summary Test abs nodes optimization in C2.
+ * @library /test/lib /
+ * @run driver compiler.c2.irTests.TestIRAbs
+ */
+
+public class TestIRAbs {
+
+    public static char [] cspecial = {
+        0, 42, 128, 256, 1024, 4096, 65535
+    };
+
+    public static int [] ispecial = {
+        0, Integer.MAX_VALUE, Integer.MIN_VALUE, -42, 42, -1, 1
+    };
+
+    public static long [] lspecial = {
+        0, Long.MAX_VALUE, Long.MIN_VALUE, -42, 42, -1, 1
+    };
+
+    public static float [] fspecial = {
+        0.0f,
+        -0.0f,
+        Float.MAX_VALUE,
+        Float.MIN_VALUE,
+        -Float.MAX_VALUE,
+        -Float.MIN_VALUE,
+        Float.NaN,
+        Float.POSITIVE_INFINITY,
+        Float.NEGATIVE_INFINITY,
+        Integer.MAX_VALUE,
+        Integer.MIN_VALUE,
+        Long.MAX_VALUE,
+        Long.MIN_VALUE,
+        -1.0f,
+        1.0f,
+        -42.0f,
+        42.0f
+    };
+
+    public static double [] dspecial = {
+        0.0,
+        -0.0,
+        Double.MAX_VALUE,
+        Double.MIN_VALUE,
+        -Double.MAX_VALUE,
+        -Double.MIN_VALUE,
+        Double.NaN,
+        Double.POSITIVE_INFINITY,
+        Double.NEGATIVE_INFINITY,
+        Integer.MAX_VALUE,
+        Integer.MIN_VALUE,
+        Long.MIN_VALUE,
+        Long.MAX_VALUE,
+        -1,
+        1,
+        42,
+        -42,
+        Math.PI,
+        Math.E,
+        Float.MAX_VALUE,
+        Float.MIN_VALUE,
+        -Float.MAX_VALUE,
+        -Float.MIN_VALUE,
+        Float.NaN,
+        Float.POSITIVE_INFINITY,
+        Float.NEGATIVE_INFINITY
+    };
+
+    public static void main(String[] args) {
+        TestFramework.run();
+    }
+
+    @Test
+    @IR(failOn = {IRNode.ABS_I, IRNode.ABS_L, IRNode.ABS_F, IRNode.ABS_D})
+    public void testAbsConstant() {
+        // Test abs(constant) optimization for int
+        Asserts.assertEquals(Integer.MAX_VALUE, Math.abs(Integer.MAX_VALUE));
+        Asserts.assertEquals(Integer.MIN_VALUE, Math.abs(Integer.MIN_VALUE));
+        Asserts.assertEquals(Integer.MAX_VALUE, Math.abs(-Integer.MAX_VALUE));
+
+        // Test abs(constant) optimization for long
+        Asserts.assertEquals(Long.MAX_VALUE, Math.abs(Long.MAX_VALUE));
+        Asserts.assertEquals(Long.MIN_VALUE, Math.abs(Long.MIN_VALUE));
+        Asserts.assertEquals(Long.MAX_VALUE, Math.abs(-Long.MAX_VALUE));
+
+        // Test abs(constant) optimization for float
+        Asserts.assertTrue(Float.isNaN(Math.abs(Float.NaN)));
+        Asserts.assertEquals(Float.POSITIVE_INFINITY, Math.abs(Float.NEGATIVE_INFINITY));
+        Asserts.assertEquals(Float.POSITIVE_INFINITY, Math.abs(Float.POSITIVE_INFINITY));
+        Asserts.assertEquals(0.0f, Math.abs(0.0f));
+        Asserts.assertEquals(0.0f, Math.abs(-0.0f));
+        Asserts.assertEquals(Float.MAX_VALUE, Math.abs(Float.MAX_VALUE));
+        Asserts.assertEquals(Float.MIN_VALUE, Math.abs(Float.MIN_VALUE));
+        Asserts.assertEquals(Float.MAX_VALUE, Math.abs(-Float.MAX_VALUE));
+        Asserts.assertEquals(Float.MIN_VALUE, Math.abs(-Float.MIN_VALUE));
+
+        // Test abs(constant) optimization for double
+        Asserts.assertTrue(Double.isNaN(Math.abs(Double.NaN)));
+        Asserts.assertEquals(Double.POSITIVE_INFINITY, Math.abs(Double.NEGATIVE_INFINITY));
+        Asserts.assertEquals(Double.POSITIVE_INFINITY, Math.abs(Double.POSITIVE_INFINITY));
+        Asserts.assertEquals(0.0, Math.abs(0.0));
+        Asserts.assertEquals(0.0, Math.abs(-0.0));
+        Asserts.assertEquals(Double.MAX_VALUE, Math.abs(Double.MAX_VALUE));
+        Asserts.assertEquals(Double.MIN_VALUE, Math.abs(Double.MIN_VALUE));
+        Asserts.assertEquals(Double.MAX_VALUE, Math.abs(-Double.MAX_VALUE));
+        Asserts.assertEquals(Double.MIN_VALUE, Math.abs(-Double.MIN_VALUE));
+    }
+
+    @Test
+    @IR(counts = {IRNode.ABS_I, "1"})
+    public int testInt0(int x) {
+        return Math.abs(Math.abs(x)); // transformed to Math.abs(x)
+    }
+
+    @Test
+    @IR(failOn = {IRNode.SUB_I})
+    @IR(counts = {IRNode.ABS_I, "1"})
+    public int testInt1(int x) {
+        return Math.abs(0 - x); // transformed to Math.abs(x)
+    }
+
+    @Run(test = {"testInt0", "testInt1"})
+    public void checkTestInt(RunInfo info) {
+        for (int i = 0; i < ispecial.length; i++) {
+            Asserts.assertEquals(Math.abs(ispecial[i]), testInt0(ispecial[i]));
+            Asserts.assertEquals(Math.abs(ispecial[i]), testInt1(ispecial[i]));
+        }
+    }
+
+    @Test
+    @IR(counts = {IRNode.ABS_L, "1"})
+    public long testLong0(long x) {
+        return Math.abs(Math.abs(x)); // transformed to Math.abs(x)
+    }
+
+    @Test
+    @IR(failOn = {IRNode.SUB_L})
+    @IR(counts = {IRNode.ABS_L, "1"})
+    public long testLong1(long x) {
+        return Math.abs(0 - x); // transformed to Math.abs(x)
+    }
+
+    @Run(test = {"testLong0", "testLong1"})
+    public void checkTestLong(RunInfo info) {
+        for (int i = 0; i < lspecial.length; i++) {
+            Asserts.assertEquals(Math.abs(lspecial[i]), testLong0(lspecial[i]));
+            Asserts.assertEquals(Math.abs(lspecial[i]), testLong1(lspecial[i]));
+        }
+    }
+
+    @Test
+    @IR(counts = {IRNode.ABS_F, "1"})
+    public float testFloat0(float x) {
+        return Math.abs(Math.abs(x)); // transformed to Math.abs(x)
+    }
+
+    @Test
+    @IR(failOn = {IRNode.SUB_F})
+    @IR(counts = {IRNode.ABS_F, "1"})
+    public float testFloat1(float x) {
+        return Math.abs(0 - x); // transformed to Math.abs(x)
+    }
+
+    @Run(test = {"testFloat0", "testFloat1"})
+    public void checkTestFloat(RunInfo info) {
+        for (int i = 0; i < fspecial.length; i++) {
+            Asserts.assertEquals(Math.abs(fspecial[i]), testFloat0(fspecial[i]));
+            Asserts.assertEquals(Math.abs(fspecial[i]), testFloat1(fspecial[i]));
+        }
+    }
+
+    @Test
+    @IR(counts = {IRNode.ABS_D, "1"})
+    public double testDouble0(double x) {
+        return Math.abs(Math.abs(x)); // transformed to Math.abs(x)
+    }
+
+    @Test
+    @IR(failOn = {IRNode.SUB_D})
+    @IR(counts = {IRNode.ABS_D, "1"})
+    public double testDouble1(double x) {
+        return Math.abs(0 - x); // transformed to Math.abs(x)
+    }
+
+    @Run(test = {"testDouble0", "testDouble1"})
+    public void checkTestDouble(RunInfo info) {
+        for (int i = 0; i < dspecial.length; i++) {
+            Asserts.assertEquals(Math.abs(dspecial[i]), testDouble0(dspecial[i]));
+            Asserts.assertEquals(Math.abs(dspecial[i]), testDouble1(dspecial[i]));
+        }
+    }
+
+    @Test
+    @IR(failOn = {IRNode.ABS_I})
+    public void testChar() {
+        for (int i = 0; i < cspecial.length; i++) {
+            Asserts.assertEquals(cspecial[i], (char) Math.abs(cspecial[i]));
+        }
+    }
+ }

test/hotspot/jtreg/compiler/lib/ir_framework/IRNode.java

@@ -136,6 +136,10 @@ public class IRNode {
     public static final String SCOPE_OBJECT = "(.*# ScObj.*" + END;
     public static final String MEMBAR = START + "MemBar" + MID + END;
 
+    public static final String ABS_I = START + "AbsI" + MID + END;
+    public static final String ABS_L = START + "AbsL" + MID + END;
+    public static final String ABS_F = START + "AbsF" + MID + END;
+    public static final String ABS_D = START + "AbsD" + MID + END;
     public static final String AND_I = START + "AndI" + MID + END;
     public static final String AND_L = START + "AndL" + MID + END;
     public static final String LSHIFT_I = START + "LShiftI" + MID + END;
@@ -145,6 +149,8 @@ public class IRNode {
     public static final String ADD_VD = START + "AddVD" + MID + END;
     public static final String SUB_I = START + "SubI" + MID + END;
     public static final String SUB_L = START + "SubL" + MID + END;
+    public static final String SUB_F = START + "SubF" + MID + END;
+    public static final String SUB_D = START + "SubD" + MID + END;
     public static final String MUL_I = START + "MulI" + MID + END;
     public static final String MUL_L = START + "MulL" + MID + END;
     public static final String CONV_I2L = START + "ConvI2L" + MID + END;