some opt

midend/llvm/instr/PhiInstr.java

@@ -0,0 +1,57 @@
+package midend.llvm.instr;
+
+import java.util.ArrayList;
+import java.util.StringJoiner;
+
+import midend.llvm.type.IrType;
+import midend.llvm.value.IrBasicBlock;
+import midend.llvm.value.IrValue;
+
+public class PhiInstr extends IrInstr {
+    private ArrayList<IrBasicBlock> predBBs;
+
+    public PhiInstr(IrType type, IrBasicBlock bblock, String name) {
+        super(type, name, IrInstrType.PHI);
+        this.setBBlock(bblock);
+        this.predBBs = new ArrayList<>(bblock.getPreds());
+        for (IrBasicBlock bb : predBBs) {
+            this.addUse(null);
+        }
+    }
+
+    public ArrayList<IrBasicBlock> getPredBBs() {
+        return predBBs;
+    }
+
+    public void setValueForPred(IrBasicBlock pred, IrValue value) {
+        int index = predBBs.indexOf(pred);
+        this.setUse(index, value);
+    }
+
+    public void deletePred(IrBasicBlock pred) {
+        int index = predBBs.indexOf(pred);
+        if (index != -1) {
+            predBBs.remove(index);
+            this.deleteUse(index);
+        }
+    }
+
+    public void replacePred(IrBasicBlock oldPred, IrBasicBlock newPred) {
+        //TODO: whether the function is needed    
+    }
+
+    public String toString() {
+        StringBuilder sb = new StringBuilder();
+        sb.append(getName());
+        sb.append(" = phi ");
+        sb.append(getType().toString());
+        for (int i = 0; i < this.predBBs.size(); i++) {
+            sb.append("[ ");
+            sb.append(getUse(i).getName());
+            sb.append(", %");
+            sb.append(this.predBBs.get(i).getName());
+            sb.append(" ]");
+        }
+        return sb.toString();
+    }
+}

midend/llvm/use/IrUser.java

@@ -18,11 +18,10 @@ public class IrUser extends IrValue {
     }
 
     public void addUse(IrValue value) {
-        if (value == null) {
-            return;
-        }
         uses.add(value);
-        value.addUser(this);
+        if (value != null) {
+            value.addUser(this);
+        }
     }
 
     public IrValue getUse(int index) {
@@ -32,6 +31,44 @@ public class IrUser extends IrValue {
         return uses.get(index);
     }
 
+    public void setUse(int index, IrValue value) {
+        if (index >= uses.size() || index < 0) {
+            return;
+        }
+        IrValue oldValue = uses.get(index);
+        if (oldValue != null) {
+            oldValue.deleteUser(this);
+        }
+        uses.set(index, value);
+        if (value != null) {
+            value.addUser(this);
+        }
+    }
+
+    public void deleteUse(IrValue value) {
+        uses.remove(value);
+        if (value != null) {
+            value.deleteUser(this);
+        }   
+    }
+
+    public void clearUses() {
+        for (IrValue value : uses) {
+            if (value != null) {
+                value.deleteUser(this);
+            }
+        }
+        uses.clear();
+    }
+
+    public void deleteUse(int index) {
+        if (index >= uses.size() || index < 0) {
+            return;
+        }
+        IrValue value = uses.get(index);
+        deleteUse(value);
+    }
+
     public int getNumUses() {
         return uses.size();
     }

midend/llvm/value/IrBasicBlock.java

@@ -35,6 +35,27 @@ public class IrBasicBlock extends IrValue {
         instr.setBBlock(this);
     }
 
+    public void addInstr(IrInstr instr, int index) {
+        instrs.add(index, instr);
+        instr.setBBlock(this);
+    }
+
+    public void deleteInstr(IrInstr instr) {
+        instrs.remove(instr);
+        instr.setBBlock(null);
+        instr.clearUses();
+        instr.clearUsers();
+    }
+
+    public void clearAllInstrs() {
+        for (IrInstr instr : instrs) {
+            instr.setBBlock(null);
+            instr.clearUses();
+            instr.clearUsers();
+        }
+        instrs.clear();
+    }
+
     public IrFuncValue getFunc() {
         return func;
     }
@@ -87,6 +108,20 @@ public class IrBasicBlock extends IrValue {
         return instrs;
     }
 
+    public IrInstr getFirstInstr() {
+        if (instrs.isEmpty()) {
+            return null;
+        }
+        return instrs.get(0);
+    }
+
+    public IrInstr getLastInstr() {
+        if (instrs.isEmpty()) {
+            return null;
+        }
+        return instrs.get(instrs.size() - 1);
+    }
+
     public void addPred(IrBasicBlock bb) {
         this.preds.add(bb);
     }
@@ -119,6 +154,14 @@ public class IrBasicBlock extends IrValue {
         return this.directDomi;
     }
 
+    public HashSet<IrBasicBlock> getDirectDomies() {
+        return directDomies;
+    }
+
+    public HashSet<IrBasicBlock> getDomiFrontier() {
+        return domiFrontier;
+    }
+
     public void toMips() {
         new MipsLabel(getMipsLabel());
         for (IrInstr instr : instrs) {

midend/llvm/value/IrFuncValue.java

@@ -45,6 +45,27 @@ public class IrFuncValue extends IrValue {
         bblocks.add(bblock);
     }
 
+    public void deleteBBlock(IrBasicBlock bblock) {
+        bblocks.remove(bblock);
+        bblock.clearAllInstrs();
+    }
+
+    public void deleteDeadBlock() {
+        ArrayList<IrBasicBlock> liveBlocks = new ArrayList<>();
+        ArrayList<IrBasicBlock> deadBlocks = new ArrayList<>();
+        for (IrBasicBlock bb : bblocks) {
+            if (!bb.getPreds().isEmpty() || bb.isEntry()) {
+                liveBlocks.add(bb);
+            } else {
+                deadBlocks.add(bb);
+            }
+        }
+        bblocks = liveBlocks;
+        for (IrBasicBlock bb : deadBlocks) {
+            bb.clearAllInstrs();
+        }
+    }
+
     public Register getRegister(IrValue value) {
         return valueRegisterMap.get(value);
     }

midend/llvm/value/IrValue.java

@@ -32,6 +32,28 @@ public class IrValue {
         users.add(user);
     }
 
+    public void deleteUser(IrUser user) {
+        users.remove(user);
+    }
+
+    public void clearUsers() {
+        ArrayList<IrUser> usersCopy = new ArrayList<>(users);
+        for (IrUser user : usersCopy) {
+            user.deleteUse(this);
+        }
+    }
+
+    public void replaceUserToAnother(IrValue newValue) {
+        ArrayList<IrUser> usersCopy = new ArrayList<>(users);
+        for (IrUser user : usersCopy) {
+            for (int i = 0; i < user.getUses().size(); i++) {
+                if (user.getUse(i) == this) {
+                    user.setUse(i, newValue);
+                }
+            }
+        }
+    }
+
     public String toString() {
         return type.toString() + " " + name;
     }