core: simplify conditions, omit redundant parenthesis

jadx-core/src/main/java/jadx/core/codegen/InsnGen.java

@@ -309,7 +309,7 @@ public class InsnGen {
 				break;
 
 			case APUT:
-				code.add(arg(insn, 0)).add('[').add(arg(insn, 1)).add("] = ").add(arg(insn, 2));
+				code.add(arg(insn, 0)).add('[').add(arg(insn.getArg(1), false)).add("] = ").add(arg(insn.getArg(2), false));
 				break;
 
 			case IGET: {

jadx-core/src/main/java/jadx/core/codegen/RegionGen.java

@@ -167,7 +167,7 @@ public class RegionGen extends InsnGen {
 				return "!" + makeCondition(condition.getArgs().get(0));
 			case AND:
 			case OR:
-				String mode = condition.getMode() == IfCondition.MODE.AND ? " && " : " || ";
+				String mode = condition.getMode() == IfCondition.Mode.AND ? " && " : " || ";
 				StringBuilder sb = new StringBuilder();
 				for (IfCondition arg : condition.getArgs()) {
 					if (sb.length() != 0) {

jadx-core/src/main/java/jadx/core/dex/regions/IfCondition.java

@@ -5,6 +5,7 @@ import jadx.core.dex.instructions.IfOp;
 import jadx.core.dex.instructions.args.InsnArg;
 import jadx.core.dex.nodes.BlockNode;
 
+import java.util.ArrayList;
 import java.util.Arrays;
 import java.util.List;
 
@@ -21,16 +22,18 @@ public final class IfCondition {
 		return new IfCondition(new Compare(insn));
 	}
 
-	public static IfCondition not(IfCondition a) {
-		return new IfCondition(MODE.NOT, Arrays.asList(a));
-	}
-
-	public static IfCondition and(IfCondition a, IfCondition b) {
-		return new IfCondition(MODE.AND, Arrays.asList(a, b));
-	}
-
-	public static IfCondition or(IfCondition a, IfCondition b) {
-		return new IfCondition(MODE.OR, Arrays.asList(a, b));
+	public static IfCondition merge(Mode mode, IfCondition a, IfCondition b) {
+		if (a.getMode() == mode) {
+			IfCondition n = new IfCondition(a);
+			n.addArg(b);
+			return n;
+		} else if (b.getMode() == mode) {
+			IfCondition n = new IfCondition(b);
+			n.addArg(a);
+			return n;
+		} else {
+			return new IfCondition(mode, Arrays.asList(a, b));
+		}
 	}
 
 	public static final class Compare {
@@ -61,30 +64,36 @@ public final class IfCondition {
 		}
 	}
 
-	public static enum MODE {
+	public static enum Mode {
 		COMPARE,
 		NOT,
 		AND,
 		OR
 	}
 
-	private final MODE mode;
+	private final Mode mode;
 	private final List<IfCondition> args;
 	private final Compare compare;
 
 	private IfCondition(Compare compare) {
-		this.mode = MODE.COMPARE;
+		this.mode = Mode.COMPARE;
 		this.compare = compare;
 		this.args = null;
 	}
 
-	private IfCondition(MODE mode, List<IfCondition> args) {
+	private IfCondition(Mode mode, List<IfCondition> args) {
 		this.mode = mode;
 		this.args = args;
 		this.compare = null;
 	}
 
-	public MODE getMode() {
+	private IfCondition(IfCondition c) {
+		this.mode = c.mode;
+		this.compare = c.compare;
+		this.args = new ArrayList<IfCondition>(c.args);
+	}
+
+	public Mode getMode() {
 		return mode;
 	}
 
@@ -92,8 +101,12 @@ public final class IfCondition {
 		return args;
 	}
 
+	public void addArg(IfCondition c) {
+		args.add(c);
+	}
+
 	public boolean isCompare() {
-		return mode == MODE.COMPARE;
+		return mode == Mode.COMPARE;
 	}
 
 	public Compare getCompare() {

jadx-core/src/main/java/jadx/core/dex/visitors/regions/RegionMaker.java

@@ -40,6 +40,7 @@ import java.util.Set;
 import org.slf4j.Logger;
 import org.slf4j.LoggerFactory;
 
+import static jadx.core.dex.regions.IfCondition.Mode;
 import static jadx.core.utils.BlockUtils.getBlockByOffset;
 import static jadx.core.utils.BlockUtils.isPathExists;
 import static jadx.core.utils.BlockUtils.selectOther;
@@ -400,6 +401,7 @@ public class RegionMaker {
 
 					IfCondition condition;
 					boolean inverted = false;
+					IfCondition nestedCondition = IfCondition.fromIfNode(nestedIfInsn);
 					if (isPathExists(bElse, nestedIfBlock)) {
 						// else branch
 						if (bThen != nbThen) {
@@ -409,7 +411,7 @@ public class RegionMaker {
 							nestedIfInsn.invertOp(nbElse.getStartOffset());
 							inverted = true;
 						}
-						condition = IfCondition.or(ifRegion.getCondition(), IfCondition.fromIfNode(nestedIfInsn));
+						condition = IfCondition.merge(Mode.OR, ifRegion.getCondition(), nestedCondition);
 					} else {
 						// then branch
 						if (bElse != nbElse) {
@@ -419,7 +421,7 @@ public class RegionMaker {
 							nestedIfInsn.invertOp(nbElse.getStartOffset());
 							inverted = true;
 						}
-						condition = IfCondition.and(ifRegion.getCondition(), IfCondition.fromIfNode(nestedIfInsn));
+						condition = IfCondition.merge(Mode.AND, ifRegion.getCondition(), nestedCondition);
 					}
 					ifRegion.setCondition(condition);
 					nestedIfBlock.getAttributes().add(AttributeFlag.SKIP);

jadx-core/src/test/java/jadx/tests/internal/TestRedundantBrackets.java

@@ -31,6 +31,17 @@ public class TestRedundantBrackets extends InternalJadxTest {
 			}
 			return b;
 		}
+
+		public void method4(int num) {
+			if (num == 4 || num == 6 || num == 8 || num == 10) {
+				method2(null);
+			}
+		}
+
+		public void method5(int a[], int n) {
+			a[1] = n * 2;
+			a[n - 1] = 1;
+		}
 	}
 
 	@Test
@@ -42,5 +53,9 @@ public class TestRedundantBrackets extends InternalJadxTest {
 		assertThat(code, containsString("if (obj instanceof String)"));
 		assertThat(code, containsString("if (a + b < 10)"));
 		assertThat(code, containsString("if ((a & b) != 0)"));
+		assertThat(code, containsString("if (num == 4 || num == 6 || num == 8 || num == 10)"));
+
+		assertThat(code, containsString("a[1] = n * 2;"));
+		assertThat(code, containsString("a[n - 1] = 1;"));
 	}
 }

jadx-samples/src/main/java/jadx/samples/TestConditions.java

@@ -50,6 +50,16 @@ public class TestConditions extends AbstractTest {
 		test1(0);
 	}
 
+	public void test4(int num) {
+		if (num == 4 || num == 6 || num == 8 || num == 10) {
+			accept("a");
+		}
+	}
+
+	public boolean test5(int num) {
+		return num > 5 && (num < 10 || num == 7);
+	}
+
 	public boolean accept(String name) {
 		return name.startsWith("Test") && name.endsWith(".class") && !name.contains("$");
 	}
@@ -71,6 +81,12 @@ public class TestConditions extends AbstractTest {
 		assertTrue(accept("Test.class"));
 
 		test3(false, false);
+
+		assertFalse(test5(4));
+		assertFalse(test5(11));
+		assertTrue(test5(6));
+		assertTrue(test5(7));
+		assertTrue(test5(8));
 		return true;
 	}