1/0 works once again, maybe.

src/main/java/net/runelite/deob/Deob.java

@@ -92,9 +92,9 @@ public class Deob
 		{	
 			new MultiplicationDeobfuscator().run(group);
 
-			//new MultiplyOneDeobfuscator().run(group);
+			new MultiplyOneDeobfuscator().run(group);
 
-			//new MultiplyZeroDeobfuscator().run(group);
+			new MultiplyZeroDeobfuscator().run(group);
 			
 			if (last == cur)
 			{

src/main/java/net/runelite/deob/deobfuscators/arithmetic/MultiplyOneDeobfuscator.java

@@ -1,6 +1,9 @@
 package net.runelite.deob.deobfuscators.arithmetic;
 
+import java.util.Collection;
+import java.util.HashSet;
 import java.util.List;
+import java.util.Set;
 import net.runelite.deob.ClassGroup;
 import net.runelite.deob.Deobfuscator;
 import net.runelite.deob.attributes.code.Instruction;
@@ -35,6 +38,9 @@ public class MultiplyOneDeobfuscator implements Deobfuscator
 					continue;
 				
 				Instructions ins = ictx.getInstruction().getInstructions();
+				if (ins == null)
+					continue;
+				
 				List<Instruction> ilist = ins.getInstructions();
 
 				if (!ilist.contains(ictx.getInstruction()))
@@ -58,6 +64,9 @@ public class MultiplyOneDeobfuscator implements Deobfuscator
 				if (removeIdx == -1)
 					continue;
 				
+				if (!MultiplicationDeobfuscator.isOnlyPath(e, ictx))
+					continue;
+				
 				ictx.removeStack(removeIdx);
 				ins.replace(ictx.getInstruction(), new NOP(ins));
 				//ins.remove(ictx.getInstruction());

src/main/java/net/runelite/deob/deobfuscators/arithmetic/MultiplyZeroDeobfuscator.java

@@ -31,6 +31,8 @@ public class MultiplyZeroDeobfuscator implements Deobfuscator
 			{
 				Instruction instruction = ictx.getInstruction();
 				Instructions ins = instruction.getInstructions();
+				if (ins == null)
+					continue;
 				
 				if (!(instruction instanceof IMul))
 					continue;
@@ -69,6 +71,9 @@ public class MultiplyZeroDeobfuscator implements Deobfuscator
 				if (!ilist.contains(instruction))
 					continue; // already done
 				
+				if (!MultiplicationDeobfuscator.isOnlyPath(e, ictx))
+					continue;
+				
 				// remove both, remove imul, push 0
 				
 				ictx.removeStack(1);

src/test/java/net/runelite/deob/deobfuscators/arithmetic/MultiplyOneDeobfuscatorTest.java

@@ -24,7 +24,7 @@ import org.junit.Test;
 public class MultiplyOneDeobfuscatorTest
 {
 	@Test
-	public void test()
+	public void testDir()
 	{
 		ClassGroup group = ClassGroupFactory.generateGroup();
 		Code code = group.findClass("test").findMethod("func").getCode();
@@ -77,4 +77,58 @@ public class MultiplyOneDeobfuscatorTest
 		
 		Assert.assertTrue(one.getInstructions() != null);
 	}
+	
+	@Test
+	public void test()
+	{
+		ClassGroup group = ClassGroupFactory.generateGroup();
+		Code code = group.findClass("test").findMethod("func").getCode();
+		Instructions ins = code.getInstructions();
+		
+		code.setMaxStack(2);
+		
+		// vars[0] = 3
+		Instruction[] prepareVariables = {
+			new IConst_3(ins),
+			new IStore_0(ins)
+		};
+		
+		for (Instruction i : prepareVariables)
+			ins.addInstruction(i);
+		
+		NOP label = new NOP(ins),
+		    label2 = new NOP(ins);
+		
+		IConst_1 one = new IConst_1(ins);
+		IMul mul = new IMul(ins);
+		
+		Instruction body[] = {
+			new SiPush(ins, (short) 256),
+			
+			new ILoad(ins, 0),
+			new If0(ins, label),
+			
+			label,
+			one,
+			
+			label2,
+			mul,
+			
+			new VReturn(ins)
+		};
+		
+		for (Instruction i : body)
+			ins.addInstruction(i);
+		
+		// check execution runs ok
+		Execution e = new Execution(group);
+		e.populateInitialMethods();
+		e.run();
+		
+		Deobfuscator d = new MultiplyOneDeobfuscator();
+		d.run(group);
+		
+		Assert.assertTrue(one.getInstructions() == null);
+		Assert.assertTrue(mul.getInstructions() == null);
+	}
 }