Merge remote-tracking branch 'origin/master' into vj/GR-69858-reflection-sec-providers

Author: vjovanov

compiler/src/jdk.graal.compiler.test/src/jdk/graal/compiler/nodes/test/SplitIfWithLoopExitTest.java

@@ -0,0 +1,107 @@
+/*
+ * Copyright (c) 2026, 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.  Oracle designates this
+ * particular file as subject to the "Classpath" exception as provided
+ * by Oracle in the LICENSE file that accompanied this code.
+ *
+ * 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 jdk.graal.compiler.nodes.test;
+
+import org.junit.Test;
+
+import jdk.graal.compiler.api.directives.GraalDirectives;
+import jdk.graal.compiler.core.test.GraalCompilerTest;
+
+/**
+ * Tests simplification of an {@code IfNode} after a merge when one successor is a loop exit.
+ */
+public class SplitIfWithLoopExitTest extends GraalCompilerTest {
+
+    private static final Object FIRST = new Object();
+    private static final Object SECOND = new Object();
+
+    /* The condition has an additional usage whose result is needed on both loop paths. The transformation is rejected. */
+    public static int sharedConditionSnippet(boolean selectFirst) {
+        int result = 0;
+        int i = 0;
+        while (i < 2) {
+            Object selected = selectFirst ? FIRST : SECOND;
+            boolean isFirst = selected == FIRST;
+            result = isFirst ? 1 : 2;
+            if (!isFirst) {
+                break;
+            }
+            GraalDirectives.controlFlowAnchor();
+            i++;
+        }
+        return result;
+    }
+
+    @Test
+    public void testSharedCondition() {
+        test("sharedConditionSnippet", true);
+        test("sharedConditionSnippet", false);
+    }
+
+    /* The condition has an additional usage confined to the loop body. The usage is specialized to true. */
+    public static int attributableConditionSnippet(boolean selectFirst) {
+        int i = 0;
+        while (i < 2) {
+            Object selected = selectFirst ? FIRST : SECOND;
+            boolean isFirst = selected == FIRST;
+            if (!isFirst) {
+                break;
+            }
+            GraalDirectives.blackhole(isFirst);
+            GraalDirectives.controlFlowAnchor();
+            i++;
+        }
+        return i;
+    }
+
+    @Test
+    public void testAttributableCondition() {
+        test("attributableConditionSnippet", true);
+        test("attributableConditionSnippet", false);
+    }
+
+    /* The condition has an additional usage confined to the loop exit. The usage is specialized to false. */
+    public static int exitConditionSnippet(boolean selectFirst) {
+        int result = 0;
+        int i = 0;
+        while (i < 2) {
+            Object selected = selectFirst ? FIRST : SECOND;
+            boolean isFirst = selected == FIRST;
+            if (!isFirst) {
+                result = isFirst ? 1 : 2;
+                break;
+            }
+            GraalDirectives.controlFlowAnchor();
+            i++;
+        }
+        return result;
+    }
+
+    @Test
+    public void testExitCondition() {
+        test("exitConditionSnippet", true);
+        test("exitConditionSnippet", false);
+    }
+}

compiler/src/jdk.graal.compiler/src/jdk/graal/compiler/nodes/IfNode.java

@@ -493,6 +493,16 @@ private boolean splitIfWithLoopExit(IfNode ifNode, SimplifierTool tool) {
          */
         coloredNodes.put(loopExitNode.loopBegin(), loopBodyBranch);
 
+        /* Additional condition usages must be attributable to a branch so they can be specialized. */
+        for (Node usage : ifNode.condition().usages()) {
+            if (usage != ifNode) {
+                NodeColor color = colorUsage(coloredNodes, usage, merge, ifNode.trueSuccessor(), ifNode.falseSuccessor());
+                if (color != NodeColor.TRUE_BRANCH && color != NodeColor.FALSE_BRANCH) {
+                    return false;
+                }
+            }
+        }
+
         EconomicMap<ValuePhiNode, ValueNode> phiReplacements = EconomicMap.create(merge.phis().count());
 
         for (PhiNode existingPhi : merge.phis()) {
@@ -507,6 +517,7 @@ private boolean splitIfWithLoopExit(IfNode ifNode, SimplifierTool tool) {
         }
 
         // Start modifying the graph
+        specializeConditionUsages(ifNode, coloredNodes);
         ifNode.graph().removeSplit(ifNode, survivingSuccessor);
 
         for (ValuePhiNode existingPhi : phiReplacements.getKeys()) {
@@ -527,6 +538,23 @@ private boolean splitIfWithLoopExit(IfNode ifNode, SimplifierTool tool) {
         return true;
     }
 
+    /**
+     * Replaces additional usages of the split condition with its result on their branch.
+     */
+    private static void specializeConditionUsages(IfNode ifNode, EconomicMap<Node, NodeColor> coloredNodes) {
+        LogicNode condition = ifNode.condition();
+        LogicConstantNode trueValue = LogicConstantNode.tautology(ifNode.graph());
+        LogicConstantNode falseValue = LogicConstantNode.contradiction(ifNode.graph());
+        for (Node usage : condition.usages().snapshot()) {
+            if (usage == ifNode) {
+                continue;
+            }
+            NodeColor color = coloredNodes.get(usage);
+            GraalError.guarantee(color == NodeColor.TRUE_BRANCH || color == NodeColor.FALSE_BRANCH, "Unexpected color %s for %s", color, usage);
+            usage.replaceAllInputs(condition, color == NodeColor.TRUE_BRANCH ? trueValue : falseValue);
+        }
+    }
+
     /**
      * Propagates the branch profile of an eliminated {@code IfNode} to its preceding {@code IfNode}
      * when one of the successors is a loop exit. This ensures that the original loop frequency is