8374896: Min/Max identity optimization opportunities missing for int and long

Reviewed-by: chagedorn, bmaillard

Author: galderz

src/hotspot/share/opto/phaseX.cpp

@@ -2680,7 +2680,7 @@ void PhaseIterGVN::add_users_of_use_to_worklist(Node* n, Node* use, Unique_Node_
   if (use->is_MinMax()) {
     for (DUIterator_Fast i2max, i2 = use->fast_outs(i2max); i2 < i2max; i2++) {
       Node* u = use->fast_out(i2);
-      if (u->Opcode() == use->Opcode()) {
+      if (u->is_MinMax()) {
         worklist.push(u);
       }
     }

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

@@ -73,6 +73,10 @@ private static String generate(CompileFramework comp) {
             .flatMap(MinMaxOp::generate)
             .forEach(testTemplateTokens::add);
 
+        // Note that for floating point Min/Max these cases below don't hold
+        generate(MinMaxOp.MIN_I, MinMaxOp.MAX_I).forEach(testTemplateTokens::add);
+        generate(MinMaxOp.MIN_L, MinMaxOp.MAX_L).forEach(testTemplateTokens::add);
+
         Stream.of(Fp16MinMaxOp.values())
             .flatMap(Fp16MinMaxOp::generate)
             .forEach(testTemplateTokens::add);
@@ -89,6 +93,38 @@ private static String generate(CompileFramework comp) {
             testTemplateTokens);
     }
 
+    static Stream<TemplateToken> generate(MinMaxOp op1, MinMaxOp op2) {
+        return Stream.of(template("a", "b", op1, op2), template("b", "a", op1, op2),
+                template("a", "b", op2, op1), template("b", "a", op2, op1)).
+            map(Template.ZeroArgs::asToken);
+    }
+
+    static Template.ZeroArgs template(String arg1, String arg2, MinMaxOp op1, MinMaxOp op2) {
+        return Template.make(() -> scope(
+            let("boxedTypeName", op1.type.boxedTypeName()),
+            let("op1", op1.name()),
+            let("op2", op2.name()),
+            let("type", op1.type.name()),
+            let("fn1", op1.functionName),
+            let("fn2", op2.functionName),
+            let("arg1", arg1),
+            let("arg2", arg2),
+            """
+            @Test
+            @IR(counts = {IRNode.#op1, "= 0", IRNode.#op2, "= 0"},
+                phase = CompilePhase.BEFORE_MACRO_EXPANSION)
+            @Arguments(values = {Argument.NUMBER_42, Argument.NUMBER_42})
+            public #type $test(#type #arg1, #type #arg2) {
+                int i;
+                for (i = -10; i < 1; i++) {
+                }
+                #type c = a * i;
+                return #boxedTypeName.#fn1(a, #boxedTypeName.#fn2(b, c));
+            }
+            """
+        ));
+    }
+
     enum MinMaxOp {
         MIN_D("min", CodeGenerationDataNameType.doubles()),
         MAX_D("max", CodeGenerationDataNameType.doubles()),