8373396: Min and Max Ideal missing AddNode::Ideal optimisations

Reviewed-by: epeter, roland

Author: galderz

src/hotspot/share/opto/addnode.cpp

@@ -1328,6 +1328,10 @@ static ConstAddOperands as_add_with_constant(Node* n) {
 }
 
 Node* MaxNode::IdealI(PhaseGVN* phase, bool can_reshape) {
+  Node* n = AddNode::Ideal(phase, can_reshape);
+  if (n != nullptr) {
+    return n;
+  }
   int opcode = Opcode();
   assert(opcode == Op_MinI || opcode == Op_MaxI, "Unexpected opcode");
   // Try to transform the following pattern, in any of its four possible

test/hotspot/jtreg/compiler/igvn/TestMinMaxIdeal.java

@@ -0,0 +1,140 @@
+/*
+ * Copyright (c) 2025 IBM Corporation. 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 8373396
+ * @summary Verify that min/max add ideal optimizations get applied correctly
+ * @modules java.base/jdk.internal.misc
+ * @library /test/lib /
+ * @run driver ${test.main.class}
+ */
+
+package compiler.igvn;
+
+import compiler.lib.compile_framework.CompileFramework;
+import compiler.lib.template_framework.Template;
+import compiler.lib.template_framework.TemplateToken;
+import compiler.lib.template_framework.library.CodeGenerationDataNameType;
+import compiler.lib.template_framework.library.PrimitiveType;
+import compiler.lib.template_framework.library.TestFrameworkClass;
+
+import java.util.Collections;
+import java.util.List;
+import java.util.stream.Stream;
+
+import static compiler.lib.template_framework.Template.let;
+import static compiler.lib.template_framework.Template.scope;
+
+public class TestMinMaxIdeal {
+    public static void main(String[] args) {
+        // Create a new CompileFramework instance.
+        CompileFramework comp = new CompileFramework();
+
+        // Add a java source file.
+        comp.addJavaSourceCode("compiler.igvn.templated.MinMaxIdeal", generate(comp));
+
+        // Compile the source file.
+        comp.compile();
+
+        comp.invoke("compiler.igvn.templated.MinMaxIdeal", "main", new Object[] {new String[] {}});
+    }
+
+    private static String generate(CompileFramework comp) {
+        // Create a list to collect all tests.
+        List<TemplateToken> testTemplateTokens = Stream.of(Op.values())
+            .map(op -> new TestGenerator(op).generate())
+            .toList();
+
+        // Create the test class, which runs all testTemplateTokens.
+        return TestFrameworkClass.render(
+            // package and class name.
+            "compiler.igvn.templated", "MinMaxIdeal",
+            // List of imports.
+            Collections.emptySet(),
+            // classpath, so the Test VM has access to the compiled class files.
+            comp.getEscapedClassPathOfCompiledClasses(),
+            // The list of tests.
+            testTemplateTokens);
+    }
+
+    enum Op {
+        MIN_I("min", CodeGenerationDataNameType.ints()),
+        MAX_I("max", CodeGenerationDataNameType.ints()),
+        MIN_L("min", CodeGenerationDataNameType.longs()),
+        MAX_L("max", CodeGenerationDataNameType.longs());
+
+        final String functionName;
+        final PrimitiveType type;
+
+        Op(String functionName, PrimitiveType type) {
+            this.functionName = functionName;
+            this.type = type;
+        }
+    }
+
+    record TestGenerator(Op op) {
+        TemplateToken generate() {
+            var template = Template.make(() -> scope(
+                let("boxedTypeName", op.type.boxedTypeName()),
+                let("op", op.name()),
+                let("type", op.type.name()),
+                let("functionName", op.functionName),
+                """
+                @Test
+                @IR(counts = {IRNode.#op, "= 1"},
+                    phase = CompilePhase.BEFORE_MACRO_EXPANSION)
+                @Arguments(values = {Argument.NUMBER_42, Argument.NUMBER_42})
+                public #type test_commute_#op(#type a, #type b) {
+                    return #boxedTypeName.#functionName(a, b) + #boxedTypeName.#functionName(b, a);
+                }
+
+                @Test
+                @IR(counts = {IRNode.#op, "= 1"},
+                    phase = CompilePhase.BEFORE_MACRO_EXPANSION)
+                @Arguments(values = {Argument.NUMBER_42})
+                public #type test_flatten_#op(#type a) {
+                    return #boxedTypeName.#functionName(#boxedTypeName.#functionName(a, 1), 2);
+                }
+
+                @Test
+                @IR(counts = {IRNode.#op, "= 2"},
+                    phase = CompilePhase.BEFORE_MACRO_EXPANSION)
+                @Arguments(values = {Argument.NUMBER_42, Argument.NUMBER_42})
+                public #type test_push_constant_left_#op(#type a, #type b) {
+                    return #boxedTypeName.#functionName(#boxedTypeName.#functionName(a, 1), b) + #boxedTypeName.#functionName(b, a);
+                }
+
+                @Test
+                @IR(counts = {IRNode.#op, "= 2"},
+                    phase = CompilePhase.BEFORE_MACRO_EXPANSION)
+                @Arguments(values = {Argument.NUMBER_42, Argument.NUMBER_42})
+                public #type test_push_constant_right_#op(#type a, #type b) {
+                    return #boxedTypeName.#functionName(a, #boxedTypeName.#functionName(b, 1)) + #boxedTypeName.#functionName(b, a);
+                }
+                """
+            ));
+            return template.asToken();
+        }
+    }
+}