[GR-52562] Add arithmetic optimizations around integer negation.

PullRequest: graal/19141
oracle · Oct 28, 2024 · 5f95334 · 5f95334
2 parents f9fb072 + 22c6b08
commit 5f95334
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Showing 3 changed files with 31 additions and 7 deletions.
diff --git a/.../jdk.graal.compiler.test/src/jdk/graal/compiler/core/test/NegateCanonicalizationTest.java b/.../jdk.graal.compiler.test/src/jdk/graal/compiler/core/test/NegateCanonicalizationTest.java
@@ -25,11 +25,12 @@
  */
 package jdk.graal.compiler.core.test;
 
+import org.junit.Test;
+
 import jdk.graal.compiler.nodes.StructuredGraph;
 import jdk.graal.compiler.nodes.calc.NegateNode;
 import jdk.graal.compiler.nodes.calc.RightShiftNode;
 import jdk.graal.compiler.nodes.calc.UnsignedRightShiftNode;
-import org.junit.Test;
 
 public class NegateCanonicalizationTest extends GraalCompilerTest {
 
@@ -49,19 +50,37 @@ public static long signExtractLong(long x) {
         return (x >> 63) >>> 63;
     }
 
-    private void checkNodes(String methodName) {
+    public static int negateNegate(int x) {
+        int var0 = -x;
+        int var1 = -(0 ^ var0);
+        return var1;
+    }
+
+    public static int negateNotDecrement(int x) {
+        return -~(x - 1);
+    }
+
+    private void checkNodesOnlyUnsignedRightShift(String methodName) {
         StructuredGraph graph = parseForCompile(getResolvedJavaMethod(methodName));
         createCanonicalizerPhase().apply(graph, getProviders());
         assertTrue(graph.getNodes().filter(NegateNode.class).count() == 0);
         assertTrue(graph.getNodes().filter(RightShiftNode.class).count() == 0);
         assertTrue(graph.getNodes().filter(UnsignedRightShiftNode.class).count() == 1);
     }
 
+    private void checkNodesNoNegate(String methodName) {
+        StructuredGraph graph = parseForCompile(getResolvedJavaMethod(methodName));
+        createCanonicalizerPhase().apply(graph, getProviders());
+        assertTrue(graph.getNodes().filter(NegateNode.class).count() == 0);
+    }
+
     @Test
     public void testNegate() {
-        checkNodes("negateInt");
-        checkNodes("negateLong");
-        checkNodes("signExtractInt");
-        checkNodes("signExtractLong");
+        checkNodesOnlyUnsignedRightShift("negateInt");
+        checkNodesOnlyUnsignedRightShift("negateLong");
+        checkNodesOnlyUnsignedRightShift("signExtractInt");
+        checkNodesOnlyUnsignedRightShift("signExtractLong");
+        checkNodesNoNegate("negateNegate");
+        checkNodesNoNegate("negateNotDecrement");
     }
 }
diff --git a/compiler/src/jdk.graal.compiler/src/jdk/graal/compiler/nodes/calc/NegateNode.java b/compiler/src/jdk.graal.compiler/src/jdk/graal/compiler/nodes/calc/NegateNode.java
@@ -73,7 +73,7 @@ protected UnaryOp<Neg> getOp(ArithmeticOpTable table) {
 
     @Override
     public ValueNode canonical(CanonicalizerTool tool, ValueNode forValue) {
-        ValueNode synonym = findSynonym(forValue, getOp(forValue));
+        ValueNode synonym = findSynonym(forValue, NodeView.DEFAULT);
         if (synonym != null) {
             return synonym;
         }

diff --git a/compiler/src/jdk.graal.compiler/src/jdk/graal/compiler/nodes/calc/NotNode.java b/compiler/src/jdk.graal.compiler/src/jdk/graal/compiler/nodes/calc/NotNode.java
@@ -32,6 +32,7 @@
 import jdk.graal.compiler.core.common.type.ArithmeticOpTable.UnaryOp.Not;
 import jdk.graal.compiler.core.common.type.Stamp;
 import jdk.graal.compiler.graph.NodeClass;
+import jdk.graal.compiler.nodes.NodeView;
 import jdk.graal.compiler.nodes.ValueNode;
 import jdk.graal.compiler.nodes.spi.ArithmeticLIRLowerable;
 import jdk.graal.compiler.nodes.spi.CanonicalizerTool;
@@ -74,6 +75,10 @@ private static ValueNode canonicalize(NotNode node, ValueNode x) {
         if (x instanceof NotNode) {
             return ((NotNode) x).getValue();
         }
+        if (x instanceof AddNode addNode && addNode.getY().isJavaConstant() && addNode.getY().asJavaConstant().asLong() == -1) {
+            // ~(x - 1) -> -x
+            return NegateNode.create(addNode.getX(), NodeView.DEFAULT);
+        }
         if (node != null) {
             return node;
         }