dev/core/test/com/google/gwt/dev/jjs/impl/DeadCodeEliminationTest.java - gwt - Git at Google

 /*
  * Copyright 2008 Google Inc.
  *
  * Licensed under the Apache License, Version 2.0 (the "License"); you may not
  * use this file except in compliance with the License. You may obtain a copy of
  * the License at
  *
  * http://www.apache.org/licenses/LICENSE-2.0
  *
  * Unless required by applicable law or agreed to in writing, software
  * distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
  * WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
  * License for the specific language governing permissions and limitations under
  * the License.
  */
 package com.google.gwt.dev.jjs.impl;

 import com.google.gwt.core.ext.TreeLogger;
 import com.google.gwt.dev.jjs.ast.JMethod;
 import com.google.gwt.dev.jjs.ast.JProgram;

 /**
  * Tests {@link DeadCodeElimination}.
  */
 public class DeadCodeEliminationTest extends OptimizerTestBase {
   /*
    * TODO: this class needs more tests, and more sophisticated cases. Especially
    * to ensure we converge in a single pass.
    */

   @Override
   public void setUp() throws Exception {
     addSnippetClassDecl("static volatile boolean b;");
     addSnippetClassDecl("static volatile boolean b1;");
     addSnippetClassDecl("static volatile int i;");
     addSnippetClassDecl("static volatile long l;");
     addSnippetClassDecl("static volatile float f;");
     addSnippetClassDecl("static volatile double d;");
     addSnippetClassDecl("static volatile String s;");
     addSnippetClassDecl("static volatile Object o;");

     runMethodInliner = false;
     runSpecializer = false;
   }

   public void testConditionalOptimizations() throws Exception {
     optimize("int", "return true ? 3 : 4;").into("return 3;");
     optimize("int", "return false ? 3 : 4;").into("return 4;");

     optimize("boolean", "return b ? true : b1;").into("return b || b1;");
     optimize("boolean", "return b ? false : b1;").into("return !b && b1;");
     optimize("boolean", "return b ? b1 : true;").into("return !b || b1;");
     optimize("boolean", "return b ? b1 : false;").into("return b && b1;");
   }

   public void testConditionalOptimizations_exactType() throws Exception {
     addSnippetClassDecl("static class A {};");
     addSnippetClassDecl("static class B extends A {};");
     optimize("int", "return new A() == new B() ? 3 : 4;")
         .intoString("return (new EntryPoint$A(), new EntryPoint$B(), 4);");
     optimize("int", "return null == new B() ? 3 : 4;")
         .intoString("return (new EntryPoint$B(), 4);");
   }

   public void testInstanceOf_exactNonNullTypes() throws Exception {
     addSnippetClassDecl("static class A {};");
     addSnippetClassDecl("static class B extends A {};");
     Result result = optimize("void",
         "boolean test;",
         "test = new A() instanceof A;",
         "test = new B() instanceof B;",
         "test = new A() instanceof B;",
         "test = new B() instanceof A;");
     result.intoString(
         "boolean test;",
         "test = (new EntryPoint$A(), true);",
         "test = (new EntryPoint$B(), true);",
         "test = (new EntryPoint$A(), false);",
         "test = (new EntryPoint$B(), true);");
   }

   public void testInstanceOf_nullability() throws Exception {
     addSnippetClassDecl("static class A {};");
     addSnippetClassDecl("static class B extends A {};");
     addSnippetClassDecl("static class C {};");
     Result result = optimize("void",
         "A a = new A();",
         "boolean test;",
         "test = null instanceof B;",
         "test = a instanceof A;");
     result.intoString(
         "EntryPoint$A a = new EntryPoint$A();",
         "boolean test;",
         "test = false;",
         "test = a != null;");
   }

   public void testSwitchOverConstant_noMatchingCase() throws Exception {
     optimize("int", "switch (0) { case 1: return 1; } return 0;")
         .into("return 0;");
   }

   public void testSwitchOverConstant_MatchingCase() throws Exception {
     optimize("int",
         "switch (1) { case 1: return 1; } return 0;")
         .into("return 1;");

     // The if isn't really the focus of the optimization, but the `into`
     // string will not compile if it is invalid Java.  It makes the opt form
     // valid java.
     optimize("int",
         "int j = 1;",
         "if (b) {",
         "  switch (1) {",
         "    case 0:",
         "    case 1:",
         "    case 2:",
         "      j = 5;",
         "    case 3:",
         "      return 1;",
         "    default:",
         "      return j;",
         "  }",
         "}",
         "return -1;")
         .into(
             "int j = 1;",
             "if (b) {",
             "  switch (1) {",
             "    case 1:",  // All of the other cases and the default are gone
             "      j = 5;", // this is a dead-store but is currently retained
             "      return 1;",
             "  }",
             "}",
             "return -1;");
   }

   public void testSwitchOverConstant_NonConstant() throws Exception {
     // doesn't optimize when there is a non-constant switch expr
     // (though, in this case, it's easy to imagine that it could)
     String[] nonConstantSwitch = new String[] {
       "int j = 1;",
       "switch (j) {",
       "  case 0: ",
       "  case 1: ",
       "  case 2: ",
       "    j = 5; ",
       "  case 3: ",
       "    return 1; ",
       "  default: ",
       "    return j; ",
       "}"
     };
     optimize("int", nonConstantSwitch).into(nonConstantSwitch);
   }

   public void testIfOptimizations() throws Exception {
     optimize("int", "if (true) return 1; return 0;").into("return 1;");
     optimize("int", "if (false) return 1; return 0;").into("return 0;");
     optimize("int", "if (true) return 1; else return 2;").into("return 1;");
     optimize("int", "if (false) return 1; else return 2;").into("return 2;");

     optimize("int", "if (true) {} else return 4; return 0;").into("return 0;");

     addSnippetClassDecl("static boolean test() { return b; }");
     optimize("int", "if (test()) {} else {}; return 0;").into(
         "test(); return 0;");
   }

   public void testIfStatementToBoolean_NotOptimization() throws Exception {
     optimize("void", "if (!b) i = 1;").intoString(
         "EntryPoint.b || (EntryPoint.i = 1);");
     optimize("void", "if (!b) i = 1; else i = 2;").intoString(
         "EntryPoint.b ? (EntryPoint.i = 2) : (EntryPoint.i = 1);");
     optimize("int", "if (!b) { return 1;} else {return 2;}").into(
         "return b ? 2 : 1;");
   }

   public void testIfStatementToBoolean_ReturnLifting() throws Exception {
     optimize("int", "if (b) return 1; return 2;").into(
         "if (b) return 1; return 2;");
     optimize("int", "if (b) { return 1; }  return 2;").into(
         "if (b) { return 1; } return 2;");
     optimize("int", "if (b) { return 1;} else {return 2;}").into(
         "return b ? 1 : 2;");
     optimize("int", "if (b) return 1; else {return 2;}").into(
         "return b ? 1 : 2;");
     optimize("int", "if (b) return 1; else return 2;").into("return b ? 1 : 2;");
     optimize("void", "if (b) return; else return;").into(
         "if (b) return; else return;");
   }

   public void testIfStatementToBoolean_ThenElseOptimization() throws Exception {
     optimize("void", "if (b) i = 1; else i = 2;").intoString(
         "EntryPoint.b ? (EntryPoint.i = 1) : (EntryPoint.i = 2);");
     optimize("void", "if (b) {i = 1;} else {i = 2;}").intoString(
         "EntryPoint.b ? (EntryPoint.i = 1) : (EntryPoint.i = 2);");
   }

   public void testIfStatementToBoolean_ThenOptimization() throws Exception {
     optimize("void", "if (b) i = 1;").intoString(
         "EntryPoint.b && (EntryPoint.i = 1);");
     optimize("void", "if (b) {i = 1;}").intoString(
         "EntryPoint.b && (EntryPoint.i = 1);");
   }

   /**
    * BUG: JInstance was marked as not having side effects whereas it all depends on the
    * whether the expression on the left has side effects.
    *
    * Reproduces Issue:7818.
    */
   public void testInstanceOfOptimization() throws Exception {
     runMethodInliner = true;
     addSnippetClassDecl(
         "static class A  { "
             + "static int f1;"
             + "static A createA() { A.f1 = 1; return new A(); } "
             + "static boolean instanceofMulti() { return (createA() instanceof A); } "
             + "static boolean inlineable() { instanceofMulti(); return true;}"
             + "}");

     optimizeExpressions(false, "void", "A.inlineable()")
         .into("A.f1 = 1; new A();");
   }

   public void testCommuteMultiExpression() throws Exception {
     runMethodInliner = true;
     addSnippetClassDecl(
         "static class A  { "
             + "static int f1;"
             + "static A createA() { A.f1 = 1; return new A(); } "
             + "static boolean booleanWithSideEffects() { createA(); return true;}"
             + "static boolean booleanWithoutSideEffects() { return true;}"
             + "static int arithmeticWithSideEffects() { createA(); return 4;}"
             + "}");

     optimizeExpressions(false, "boolean", "true && A.booleanWithoutSideEffects()")
         .intoString("return true;");

     optimizeExpressions(false, "boolean", "true && A.booleanWithSideEffects()")
         .intoString("return (EntryPoint$A.f1 = 1, new EntryPoint$A(), true);");

     optimizeExpressions(false, "boolean", "false && A.booleanWithSideEffects()")
         .intoString("return false;");

     optimizeExpressions(false, "int", "3 + A.arithmeticWithSideEffects()")
         .intoString("return (EntryPoint$A.f1 = 1, new EntryPoint$A(), 7);");
   }

   public void testStringOptimizations() throws Exception {
     runMethodInliner = true;
     addSnippetClassDecl(
         "static class A  { ",
         "  final static String s1 = \"a\";",
         "  final static String s2 = \"a\";",
         "  final static String s3 = \"b\";",
         "  final static String s4 = null;",
         "}");

     // TODO(rluble): This test is not 100% meaninful as the JDT performs some optimizations for us.
     optimizeExpressions(false, "boolean", "\"a\".equals(\"a\")")
         .into("return true;");
     optimizeExpressions(false, "boolean", "\"a\" == \"a\"")
         .into("return true;");
     optimizeExpressions(false, "boolean", "\"a\" != \"b\"")
         .into("return true;");
     optimizeExpressions(false, "boolean", "A.s1.equals(A.s1)")
         .into("return true;");
     optimizeExpressions(false, "boolean", "A.s1 == A.s1")
         .into("return true;");
     optimizeExpressions(false, "boolean", "A.s1 == \"a\"")
         .into("return true;");
     optimizeExpressions(false, "boolean", "\"a\" != null")
         .into("return true;");
     optimizeExpressions(false, "boolean", "\"a\".equals(A.s2)")
         .into("return true;");
     optimizeExpressions(false, "boolean", "!\"a\".equals(A.s3)")
         .into("return true;");
     optimizeExpressions(false, "boolean", "\"a\" == A.s2")
         .into("return true;");
     optimizeExpressions(false, "boolean", "\"a\" != A.s3")
         .into("return true;");
     optimizeExpressions(false, "boolean", "A.s1.equals(A.s2)")
         .into("return true;");
     // Next two are not directly optimizable because of inserted clinits.
     // optimizeExpressions(false, "boolean", "\"a\" != A.s4")
     //     .into("return true;");
     // optimizeExpressions(false, "boolean", "A.s4 == null")
     //    .into("return true;");
   }

   public void testStringOptimizations_withSpecializer() throws Exception {
     runSpecializer = true;
     testStringOptimizations();
   }

   public void testDoOptimization() throws Exception {
     optimize("void", "do {} while (b);").intoString(
         "do;",
         "while (EntryPoint.b);");
     optimize("void", "do {} while (true);").intoString(
         "do;",
         "while (true);");
     optimize("void", "do {} while (false);").intoString("");
     optimize("void", "do { i++; } while (false);").intoString("++EntryPoint.i;");
     optimize("void", "do { break; } while (false);").intoString(
         "do {",
         "  break;",
         "} while (false);");
   }

   public void testMultiExpressionOptimization() throws Exception {
     runMethodInliner = true;
     addSnippetClassDecl(
         "static class A  { ",
         "  static int f;",
         "  static { if (4-f ==0) f=4; }",
         "  static boolean t() { return true; }",
         "  static boolean f() { return false; }",
         "  static boolean notInlineable() { if (4-f == 0) return true;return false;}",
         "}");

     addSnippetClassDecl(
         "static class B  { ",
         "  static boolean inlineableOr() { return A.t() || A.notInlineable(); }",
         "  static boolean inlineableAnd() { return A.t() && A.notInlineable(); }",
         "}");

     optimize("void", "B.inlineableAnd();")
         .intoString("EntryPoint$A.$clinit();\nEntryPoint$A.notInlineable();");
     optimize("void", "B.inlineableOr();")
         .intoString("EntryPoint$A.$clinit();");
   }

   public void testOptimizeStringCalls() throws Exception {
     // Note: we're limited here by the methods declared in the mock String in
     // JJSTestBase#addBuiltinClasses

     // String.length
     optimize("int", "return \"abc\".length();").intoString("return 3;");
     optimize("int", "return s.length();").intoString("return EntryPoint.s.length();");

     // String.charAt
     optimize("char", "return \"abc\".charAt(1);").intoString("return 'b';");
     optimize("char", "return s.charAt(1);").intoString("return EntryPoint.s.charAt(1);");

     // String.toString
     optimize("String", "return \"a\".toString();").intoString("return \"a\";");
     optimize("String", "return s.toString();").intoString("return EntryPoint.s.toString();");
     optimize("String", "return o.toString();").intoString("return EntryPoint.o.toString();");

     // String.hashCode: never optimized
     optimize("int", "return \"abc\".hashCode();").intoString("return \"abc\".hashCode();");
     optimize("int", "return s.hashCode();").intoString("return EntryPoint.s.hashCode();");

     // String.equals
     optimize("boolean", "return \"a\".equals(\"a\");").intoString("return true;");
     optimize("boolean", "return \"a\".equals(\"b\");").intoString("return false;");
     optimize("boolean", "return s.equals(\"a\");")
         .intoString("return EntryPoint.s.equals(\"a\");");

     // String concat
     optimize("String", "return \"a\" + \"a\";").intoString("return \"aa\";");
     optimize("String", "return \"a\" + 1;").intoString("return \"a1\";");
     optimize("String", "return \"a\" + '1';").intoString("return \"a1\";");
     optimize("String", "return \"a\" +  1L;").intoString("return \"a1\";");
   }

   public void testSubtractFromZero() throws Exception {
     optimize("int", "return 0 - i;").intoString("return -EntryPoint.i;");
     optimize("long", "return 0 - l;").intoString("return -EntryPoint.l;");
     // Verify that float/double subtracts from zero aren't replaced, since they
     // are needed for obscure IEEE754 functionality -- specifically, converting
     // 0.0 - v into -v means the sign of the result is the opposite of the input
     // rather than always being positive.
     optimize("float", "return 0.0F - f;").intoString("return 0.0 - EntryPoint.f;");
     optimize("double", "return 0.0 - d;").intoString("return 0.0 - EntryPoint.d;");
   }

   public void testFloatingPoint() throws Exception {
     // Internally we represent float literals as double, so here we make sure that 1.1f is
     // is printed as a double with the right precision.
     optimize("float", "return 1.1f;").intoString("return " + String.format("%.16g", (double) 1.1f) +
         ";");
     optimize("boolean", "return 2d > 1;").intoString("return true;");
     optimize("boolean", "return 1 < 2d;").intoString("return true;");
   }

   public void testMultiExpression_RedundantClinitRemoval() throws Exception {
     addSnippetClassDecl(
         "static class A  { "
             + "static int f1;"
             + "static int f2;"
             + "static { f1 = 1; }"
             + "static void m1() { } "
             + "}" +
         "static class B extends A  { "
             + "static int f3;"
             + "static int f4;"
             + "static { f3 = 1; }"
             + "static void m2() { } "
             + "}");

     optimizeExpressions(true, "void", "A.m1()", "A.m1()").intoString("EntryPoint$A.$clinit();\n"
         + "EntryPoint$A.m1();\n"
         + "EntryPoint$A.m1();");
     optimizeExpressions(true, "void", "B.m2()", "A.m1()").intoString("EntryPoint$B.$clinit();\n"
         + "EntryPoint$B.m2();\n"
         + "EntryPoint$A.m1();");
     optimizeExpressions(true, "void", "A.m1()", "B.m2()").intoString("EntryPoint$A.$clinit();\n"
         + "EntryPoint$A.m1();\n"
         + "EntryPoint$B.$clinit();\n"
         + "EntryPoint$B.m2();");
   }

   private boolean runMethodInliner;
   private boolean runSpecializer;

   @Override
   protected boolean doOptimizeMethod(TreeLogger logger, JProgram program, JMethod method) {
     if (runMethodInliner) {
       MethodInliner.exec(program);
     }
     if (runSpecializer) {
       Finalizer.exec(program); // required so that method is marked final
       MakeCallsStatic.exec(program, false); // required so that method is static
       TypeTightener.exec(program); // required so that the parameter types are tightened
       MethodCallSpecializer.exec(program);
     }

     OptimizerStats result = DeadCodeElimination.exec(program, method);
     if (result.didChange()) {
       // Make sure we converge in one pass.
       //
       // TODO(rluble): It does not appear to be true in general unless we iterate until a
       // fixpoint in exec().
       //
       // Example:
       //
       //     Constructor( ) { deadcode }
       //     m( new Constructor(); }
       //
       // If m is processed first, it will see the constructor as having side effects.
       // Then the constructor will become empty enabling m() become empty in the next round.
       //
       assertFalse(DeadCodeElimination.exec(program, method).didChange());
     }
     return result.didChange();
   }
 }
	/*
	* Copyright 2008 Google Inc.
	*
	* Licensed under the Apache License, Version 2.0 (the "License"); you may not
	* use this file except in compliance with the License. You may obtain a copy of
	* the License at
	*
	* http://www.apache.org/licenses/LICENSE-2.0
	*
	* Unless required by applicable law or agreed to in writing, software
	* distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
	* WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
	* License for the specific language governing permissions and limitations under
	* the License.
	*/
	package com.google.gwt.dev.jjs.impl;

	import com.google.gwt.core.ext.TreeLogger;
	import com.google.gwt.dev.jjs.ast.JMethod;
	import com.google.gwt.dev.jjs.ast.JProgram;

	/**
	* Tests {@link DeadCodeElimination}.
	*/
	public class DeadCodeEliminationTest extends OptimizerTestBase {
	/*
	* TODO: this class needs more tests, and more sophisticated cases. Especially
	* to ensure we converge in a single pass.
	*/

	@Override
	public void setUp() throws Exception {
	addSnippetClassDecl("static volatile boolean b;");
	addSnippetClassDecl("static volatile boolean b1;");
	addSnippetClassDecl("static volatile int i;");
	addSnippetClassDecl("static volatile long l;");
	addSnippetClassDecl("static volatile float f;");
	addSnippetClassDecl("static volatile double d;");
	addSnippetClassDecl("static volatile String s;");
	addSnippetClassDecl("static volatile Object o;");

	runMethodInliner = false;
	runSpecializer = false;
	}

	public void testConditionalOptimizations() throws Exception {
	optimize("int", "return true ? 3 : 4;").into("return 3;");
	optimize("int", "return false ? 3 : 4;").into("return 4;");

	optimize("boolean", "return b ? true : b1;").into("return b \|\| b1;");
	optimize("boolean", "return b ? false : b1;").into("return !b && b1;");
	optimize("boolean", "return b ? b1 : true;").into("return !b \|\| b1;");
	optimize("boolean", "return b ? b1 : false;").into("return b && b1;");
	}

	public void testConditionalOptimizations_exactType() throws Exception {
	addSnippetClassDecl("static class A {};");
	addSnippetClassDecl("static class B extends A {};");
	optimize("int", "return new A() == new B() ? 3 : 4;")
	.intoString("return (new EntryPoint$A(), new EntryPoint$B(), 4);");
	optimize("int", "return null == new B() ? 3 : 4;")
	.intoString("return (new EntryPoint$B(), 4);");
	}

	public void testInstanceOf_exactNonNullTypes() throws Exception {
	addSnippetClassDecl("static class A {};");
	addSnippetClassDecl("static class B extends A {};");
	Result result = optimize("void",
	"boolean test;",
	"test = new A() instanceof A;",
	"test = new B() instanceof B;",
	"test = new A() instanceof B;",
	"test = new B() instanceof A;");
	result.intoString(
	"boolean test;",
	"test = (new EntryPoint$A(), true);",
	"test = (new EntryPoint$B(), true);",
	"test = (new EntryPoint$A(), false);",
	"test = (new EntryPoint$B(), true);");
	}

	public void testInstanceOf_nullability() throws Exception {
	addSnippetClassDecl("static class A {};");
	addSnippetClassDecl("static class B extends A {};");
	addSnippetClassDecl("static class C {};");
	Result result = optimize("void",
	"A a = new A();",
	"boolean test;",
	"test = null instanceof B;",
	"test = a instanceof A;");
	result.intoString(
	"EntryPoint$A a = new EntryPoint$A();",
	"boolean test;",
	"test = false;",
	"test = a != null;");
	}

	public void testSwitchOverConstant_noMatchingCase() throws Exception {
	optimize("int", "switch (0) { case 1: return 1; } return 0;")
	.into("return 0;");
	}

	public void testSwitchOverConstant_MatchingCase() throws Exception {
	optimize("int",
	"switch (1) { case 1: return 1; } return 0;")
	.into("return 1;");

	// The if isn't really the focus of the optimization, but the `into`
	// string will not compile if it is invalid Java. It makes the opt form
	// valid java.
	optimize("int",
	"int j = 1;",
	"if (b) {",
	" switch (1) {",
	" case 0:",
	" case 1:",
	" case 2:",
	" j = 5;",
	" case 3:",
	" return 1;",
	" default:",
	" return j;",
	" }",
	"}",
	"return -1;")
	.into(
	"int j = 1;",
	"if (b) {",
	" switch (1) {",
	" case 1:", // All of the other cases and the default are gone
	" j = 5;", // this is a dead-store but is currently retained
	" return 1;",
	" }",
	"}",
	"return -1;");
	}

	public void testSwitchOverConstant_NonConstant() throws Exception {
	// doesn't optimize when there is a non-constant switch expr
	// (though, in this case, it's easy to imagine that it could)
	String[] nonConstantSwitch = new String[] {
	"int j = 1;",
	"switch (j) {",
	" case 0: ",
	" case 1: ",
	" case 2: ",
	" j = 5; ",
	" case 3: ",
	" return 1; ",
	" default: ",
	" return j; ",
	"}"
	};
	optimize("int", nonConstantSwitch).into(nonConstantSwitch);
	}

	public void testIfOptimizations() throws Exception {
	optimize("int", "if (true) return 1; return 0;").into("return 1;");
	optimize("int", "if (false) return 1; return 0;").into("return 0;");
	optimize("int", "if (true) return 1; else return 2;").into("return 1;");
	optimize("int", "if (false) return 1; else return 2;").into("return 2;");

	optimize("int", "if (true) {} else return 4; return 0;").into("return 0;");

	addSnippetClassDecl("static boolean test() { return b; }");
	optimize("int", "if (test()) {} else {}; return 0;").into(
	"test(); return 0;");
	}

	public void testIfStatementToBoolean_NotOptimization() throws Exception {
	optimize("void", "if (!b) i = 1;").intoString(
	"EntryPoint.b \|\| (EntryPoint.i = 1);");
	optimize("void", "if (!b) i = 1; else i = 2;").intoString(
	"EntryPoint.b ? (EntryPoint.i = 2) : (EntryPoint.i = 1);");
	optimize("int", "if (!b) { return 1;} else {return 2;}").into(
	"return b ? 2 : 1;");
	}

	public void testIfStatementToBoolean_ReturnLifting() throws Exception {
	optimize("int", "if (b) return 1; return 2;").into(
	"if (b) return 1; return 2;");
	optimize("int", "if (b) { return 1; } return 2;").into(
	"if (b) { return 1; } return 2;");
	optimize("int", "if (b) { return 1;} else {return 2;}").into(
	"return b ? 1 : 2;");
	optimize("int", "if (b) return 1; else {return 2;}").into(
	"return b ? 1 : 2;");
	optimize("int", "if (b) return 1; else return 2;").into("return b ? 1 : 2;");
	optimize("void", "if (b) return; else return;").into(
	"if (b) return; else return;");
	}

	public void testIfStatementToBoolean_ThenElseOptimization() throws Exception {
	optimize("void", "if (b) i = 1; else i = 2;").intoString(
	"EntryPoint.b ? (EntryPoint.i = 1) : (EntryPoint.i = 2);");
	optimize("void", "if (b) {i = 1;} else {i = 2;}").intoString(
	"EntryPoint.b ? (EntryPoint.i = 1) : (EntryPoint.i = 2);");
	}

	public void testIfStatementToBoolean_ThenOptimization() throws Exception {
	optimize("void", "if (b) i = 1;").intoString(
	"EntryPoint.b && (EntryPoint.i = 1);");
	optimize("void", "if (b) {i = 1;}").intoString(
	"EntryPoint.b && (EntryPoint.i = 1);");
	}

	/**
	* BUG: JInstance was marked as not having side effects whereas it all depends on the
	* whether the expression on the left has side effects.
	*
	* Reproduces Issue:7818.
	*/
	public void testInstanceOfOptimization() throws Exception {
	runMethodInliner = true;
	addSnippetClassDecl(
	"static class A { "
	+ "static int f1;"
	+ "static A createA() { A.f1 = 1; return new A(); } "
	+ "static boolean instanceofMulti() { return (createA() instanceof A); } "
	+ "static boolean inlineable() { instanceofMulti(); return true;}"
	+ "}");

	optimizeExpressions(false, "void", "A.inlineable()")
	.into("A.f1 = 1; new A();");
	}

	public void testCommuteMultiExpression() throws Exception {
	runMethodInliner = true;
	addSnippetClassDecl(
	"static class A { "
	+ "static int f1;"
	+ "static A createA() { A.f1 = 1; return new A(); } "
	+ "static boolean booleanWithSideEffects() { createA(); return true;}"
	+ "static boolean booleanWithoutSideEffects() { return true;}"
	+ "static int arithmeticWithSideEffects() { createA(); return 4;}"
	+ "}");

	optimizeExpressions(false, "boolean", "true && A.booleanWithoutSideEffects()")
	.intoString("return true;");

	optimizeExpressions(false, "boolean", "true && A.booleanWithSideEffects()")
	.intoString("return (EntryPoint$A.f1 = 1, new EntryPoint$A(), true);");

	optimizeExpressions(false, "boolean", "false && A.booleanWithSideEffects()")
	.intoString("return false;");

	optimizeExpressions(false, "int", "3 + A.arithmeticWithSideEffects()")
	.intoString("return (EntryPoint$A.f1 = 1, new EntryPoint$A(), 7);");
	}

	public void testStringOptimizations() throws Exception {
	runMethodInliner = true;
	addSnippetClassDecl(
	"static class A { ",
	" final static String s1 = \"a\";",
	" final static String s2 = \"a\";",
	" final static String s3 = \"b\";",
	" final static String s4 = null;",
	"}");

	// TODO(rluble): This test is not 100% meaninful as the JDT performs some optimizations for us.
	optimizeExpressions(false, "boolean", "\"a\".equals(\"a\")")
	.into("return true;");
	optimizeExpressions(false, "boolean", "\"a\" == \"a\"")
	.into("return true;");
	optimizeExpressions(false, "boolean", "\"a\" != \"b\"")
	.into("return true;");
	optimizeExpressions(false, "boolean", "A.s1.equals(A.s1)")
	.into("return true;");
	optimizeExpressions(false, "boolean", "A.s1 == A.s1")
	.into("return true;");
	optimizeExpressions(false, "boolean", "A.s1 == \"a\"")
	.into("return true;");
	optimizeExpressions(false, "boolean", "\"a\" != null")
	.into("return true;");
	optimizeExpressions(false, "boolean", "\"a\".equals(A.s2)")
	.into("return true;");
	optimizeExpressions(false, "boolean", "!\"a\".equals(A.s3)")
	.into("return true;");
	optimizeExpressions(false, "boolean", "\"a\" == A.s2")
	.into("return true;");
	optimizeExpressions(false, "boolean", "\"a\" != A.s3")
	.into("return true;");
	optimizeExpressions(false, "boolean", "A.s1.equals(A.s2)")
	.into("return true;");
	// Next two are not directly optimizable because of inserted clinits.
	// optimizeExpressions(false, "boolean", "\"a\" != A.s4")
	// .into("return true;");
	// optimizeExpressions(false, "boolean", "A.s4 == null")
	// .into("return true;");
	}

	public void testStringOptimizations_withSpecializer() throws Exception {
	runSpecializer = true;
	testStringOptimizations();
	}

	public void testDoOptimization() throws Exception {
	optimize("void", "do {} while (b);").intoString(
	"do;",
	"while (EntryPoint.b);");
	optimize("void", "do {} while (true);").intoString(
	"do;",
	"while (true);");
	optimize("void", "do {} while (false);").intoString("");
	optimize("void", "do { i++; } while (false);").intoString("++EntryPoint.i;");
	optimize("void", "do { break; } while (false);").intoString(
	"do {",
	" break;",
	"} while (false);");
	}

	public void testMultiExpressionOptimization() throws Exception {
	runMethodInliner = true;
	addSnippetClassDecl(
	"static class A { ",
	" static int f;",
	" static { if (4-f ==0) f=4; }",
	" static boolean t() { return true; }",
	" static boolean f() { return false; }",
	" static boolean notInlineable() { if (4-f == 0) return true;return false;}",
	"}");

	addSnippetClassDecl(
	"static class B { ",
	" static boolean inlineableOr() { return A.t() \|\| A.notInlineable(); }",
	" static boolean inlineableAnd() { return A.t() && A.notInlineable(); }",
	"}");

	optimize("void", "B.inlineableAnd();")
	.intoString("EntryPoint$A.$clinit();\nEntryPoint$A.notInlineable();");
	optimize("void", "B.inlineableOr();")
	.intoString("EntryPoint$A.$clinit();");
	}

	public void testOptimizeStringCalls() throws Exception {
	// Note: we're limited here by the methods declared in the mock String in
	// JJSTestBase#addBuiltinClasses

	// String.length
	optimize("int", "return \"abc\".length();").intoString("return 3;");
	optimize("int", "return s.length();").intoString("return EntryPoint.s.length();");

	// String.charAt
	optimize("char", "return \"abc\".charAt(1);").intoString("return 'b';");
	optimize("char", "return s.charAt(1);").intoString("return EntryPoint.s.charAt(1);");

	// String.toString
	optimize("String", "return \"a\".toString();").intoString("return \"a\";");
	optimize("String", "return s.toString();").intoString("return EntryPoint.s.toString();");
	optimize("String", "return o.toString();").intoString("return EntryPoint.o.toString();");

	// String.hashCode: never optimized
	optimize("int", "return \"abc\".hashCode();").intoString("return \"abc\".hashCode();");
	optimize("int", "return s.hashCode();").intoString("return EntryPoint.s.hashCode();");

	// String.equals
	optimize("boolean", "return \"a\".equals(\"a\");").intoString("return true;");
	optimize("boolean", "return \"a\".equals(\"b\");").intoString("return false;");
	optimize("boolean", "return s.equals(\"a\");")
	.intoString("return EntryPoint.s.equals(\"a\");");

	// String concat
	optimize("String", "return \"a\" + \"a\";").intoString("return \"aa\";");
	optimize("String", "return \"a\" + 1;").intoString("return \"a1\";");
	optimize("String", "return \"a\" + '1';").intoString("return \"a1\";");
	optimize("String", "return \"a\" + 1L;").intoString("return \"a1\";");
	}

	public void testSubtractFromZero() throws Exception {
	optimize("int", "return 0 - i;").intoString("return -EntryPoint.i;");
	optimize("long", "return 0 - l;").intoString("return -EntryPoint.l;");
	// Verify that float/double subtracts from zero aren't replaced, since they
	// are needed for obscure IEEE754 functionality -- specifically, converting
	// 0.0 - v into -v means the sign of the result is the opposite of the input
	// rather than always being positive.
	optimize("float", "return 0.0F - f;").intoString("return 0.0 - EntryPoint.f;");
	optimize("double", "return 0.0 - d;").intoString("return 0.0 - EntryPoint.d;");
	}

	public void testFloatingPoint() throws Exception {
	// Internally we represent float literals as double, so here we make sure that 1.1f is
	// is printed as a double with the right precision.
	optimize("float", "return 1.1f;").intoString("return " + String.format("%.16g", (double) 1.1f) +
	";");
	optimize("boolean", "return 2d > 1;").intoString("return true;");
	optimize("boolean", "return 1 < 2d;").intoString("return true;");
	}

	public void testMultiExpression_RedundantClinitRemoval() throws Exception {
	addSnippetClassDecl(
	"static class A { "
	+ "static int f1;"
	+ "static int f2;"
	+ "static { f1 = 1; }"
	+ "static void m1() { } "
	+ "}" +
	"static class B extends A { "
	+ "static int f3;"
	+ "static int f4;"
	+ "static { f3 = 1; }"
	+ "static void m2() { } "
	+ "}");

	optimizeExpressions(true, "void", "A.m1()", "A.m1()").intoString("EntryPoint$A.$clinit();\n"
	+ "EntryPoint$A.m1();\n"
	+ "EntryPoint$A.m1();");
	optimizeExpressions(true, "void", "B.m2()", "A.m1()").intoString("EntryPoint$B.$clinit();\n"
	+ "EntryPoint$B.m2();\n"
	+ "EntryPoint$A.m1();");
	optimizeExpressions(true, "void", "A.m1()", "B.m2()").intoString("EntryPoint$A.$clinit();\n"
	+ "EntryPoint$A.m1();\n"
	+ "EntryPoint$B.$clinit();\n"
	+ "EntryPoint$B.m2();");
	}

	private boolean runMethodInliner;
	private boolean runSpecializer;

	@Override
	protected boolean doOptimizeMethod(TreeLogger logger, JProgram program, JMethod method) {
	if (runMethodInliner) {
	MethodInliner.exec(program);
	}
	if (runSpecializer) {
	Finalizer.exec(program); // required so that method is marked final
	MakeCallsStatic.exec(program, false); // required so that method is static
	TypeTightener.exec(program); // required so that the parameter types are tightened
	MethodCallSpecializer.exec(program);
	}

	OptimizerStats result = DeadCodeElimination.exec(program, method);
	if (result.didChange()) {
	// Make sure we converge in one pass.
	//
	// TODO(rluble): It does not appear to be true in general unless we iterate until a
	// fixpoint in exec().
	//
	// Example:
	//
	// Constructor( ) { deadcode }
	// m( new Constructor(); }
	//
	// If m is processed first, it will see the constructor as having side effects.
	// Then the constructor will become empty enabling m() become empty in the next round.
	//
	assertFalse(DeadCodeElimination.exec(program, method).didChange());
	}
	return result.didChange();
	}
	}