Clean up code, implement array indexing stuff

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@1340 91177308-0d34-0410-b5e6-96231b3b80d8

1 files changed, 175 insertions, 423 deletions

diff --git a/lib/Transforms/LevelRaise.cpp b/lib/Transforms/LevelRaise.cpp
index 78bb2eb..3472dec 100644
--- a/lib/Transforms/LevelRaise.cpp
+++ b/lib/Transforms/LevelRaise.cpp
@@ -2,30 +2,7 @@
 //
 // This file implements the 'raising' part of the LevelChange API.  This is
 // useful because, in general, it makes the LLVM code terser and easier to
-// analyze.  Note that it is good to run DCE after doing this transformation.
-//
-//  Eliminate silly things in the source that do not effect the level, but do
-//  clean up the code:
-//    * Casts of casts
-//    - getelementptr/load & getelementptr/store are folded into a direct
-//      load or store
-//    - Convert this code (for both alloca and malloc):
-//          %reg110 = shl uint %n, ubyte 2          ;;<uint>
-//          %reg108 = alloca ubyte, uint %reg110            ;;<ubyte*>
-//          %cast76 = cast ubyte* %reg108 to uint*          ;;<uint*>
-//      To: %cast76 = alloca uint, uint %n
-//   Convert explicit addressing to use getelementptr instruction where possible
-//      - ...
-//
-//   Convert explicit addressing on pointers to use getelementptr instruction.
-//    - If a pointer is used by arithmetic operation, insert an array casted
-//      version into the source program, only for the following pointer types:
-//        * Method argument pointers
-//        - Pointers returned by alloca or malloc
-//        - Pointers returned by function calls
-//    - If a pointer is indexed with a value scaled by a constant size equal
-//      to the element size of the array, the expression is replaced with a
-//      getelementptr instruction.
+// analyze.
 //
 //===----------------------------------------------------------------------===//
 
@@ -43,7 +20,7 @@
 
 #include "llvm/Assembly/Writer.h"
 
-//#define DEBUG_PEEPHOLE_INSTS 1
+#define DEBUG_PEEPHOLE_INSTS 1
 
 #ifdef DEBUG_PEEPHOLE_INSTS
 #define PRINT_PEEPHOLE(ID, NUM, I)            \
@@ -68,211 +45,12 @@
 // cast instruction would cause the underlying bits to change.
 //
 static inline bool isReinterpretingCast(const CastInst *CI) {
-  return !losslessCastableTypes(CI->getOperand(0)->getType(), CI->getType());
+  return!CI->getOperand(0)->getType()->isLosslesslyConvertableTo(CI->getType());
 }
 
 
 
 
-// DoInsertArrayCast - If the argument value has a pointer type, and if the
-// argument value is used as an array, insert a cast before the specified 
-// basic block iterator that casts the value to an array pointer.  Return the
-// new cast instruction (in the CastResult var), or null if no cast is inserted.
-//
-static bool DoInsertArrayCast(Method *CurMeth, Value *V, BasicBlock *BB,
-			      BasicBlock::iterator &InsertBefore,
-			      CastInst *&CastResult) {
-  const PointerType *ThePtrType = dyn_cast<PointerType>(V->getType());
-  if (!ThePtrType) return false;
-  bool InsertCast = false;
-
-  for (Value::use_iterator I = V->use_begin(), E = V->use_end(); I != E; ++I) {
-    Instruction *Inst = cast<Instruction>(*I);
-    switch (Inst->getOpcode()) {
-    default: break;                  // Not an interesting use...
-    case Instruction::Add:           // It's being used as an array index!
-  //case Instruction::Sub:
-      InsertCast = true;
-      break;
-    case Instruction::Cast:          // There is already a cast instruction!
-      if (const PointerType *PT = dyn_cast<const PointerType>(Inst->getType()))
-	if (const ArrayType *AT = dyn_cast<const ArrayType>(PT->getValueType()))
-	  if (AT->getElementType() == ThePtrType->getValueType()) {
-	    // Cast already exists! Return the existing one!
-	    CastResult = cast<CastInst>(Inst);
-	    return false;       // No changes made to program though...
-	  }
-      break;
-    }
-  }
-
-  if (!InsertCast) return false;  // There is no reason to insert a cast!
-
-  // Insert a cast!
-  const Type *ElTy = ThePtrType->getValueType();
-  const PointerType *DestTy = PointerType::get(ArrayType::get(ElTy));
-
-  CastResult = new CastInst(V, DestTy);
-  BB->getInstList().insert(InsertBefore, CastResult);
-  //cerr << "Inserted cast: " << CastResult;
-  return true;            // Made a change!
-}
-
-
-// DoInsertArrayCasts - Loop over all "incoming" values in the specified method,
-// inserting a cast for pointer values that are used as arrays. For our
-// purposes, an incoming value is considered to be either a value that is 
-// either a method parameter, a value created by alloca or malloc, or a value
-// returned from a function call.  All casts are kept attached to their original
-// values through the PtrCasts map.
-//
-static bool DoInsertArrayCasts(Method *M, map<Value*, CastInst*> &PtrCasts) {
-  assert(!M->isExternal() && "Can't handle external methods!");
-
-  // Insert casts for all arguments to the function...
-  bool Changed = false;
-  BasicBlock *CurBB = M->front();
-  BasicBlock::iterator It = CurBB->begin();
-  for (Method::ArgumentListType::iterator AI = M->getArgumentList().begin(), 
-	 AE = M->getArgumentList().end(); AI != AE; ++AI) {
-    CastInst *TheCast = 0;
-    if (DoInsertArrayCast(M, *AI, CurBB, It, TheCast)) {
-      It = CurBB->begin();      // We might have just invalidated the iterator!
-      Changed = true;           // Yes we made a change
-      ++It;                     // Insert next cast AFTER this one...
-    }
-
-    if (TheCast)                // Is there a cast associated with this value?
-      PtrCasts[*AI] = TheCast;  // Yes, add it to the map...
-  }
-
-  // TODO: insert casts for alloca, malloc, and function call results.  Also, 
-  // look for pointers that already have casts, to add to the map.
-
-  return Changed;
-}
-
-
-
-
-// DoElminatePointerArithmetic - Loop over each incoming pointer variable,
-// replacing indexing arithmetic with getelementptr calls.
-//
-static bool DoEliminatePointerArithmetic(const pair<Value*, CastInst*> &Val) {
-  Value    *V  = Val.first;   // The original pointer
-  CastInst *CV = Val.second;  // The array casted version of the pointer...
-
-  for (Value::use_iterator I = V->use_begin(), E = V->use_end(); I != E; ++I) {
-    Instruction *Inst = cast<Instruction>(*I);
-    if (Inst->getOpcode() != Instruction::Add) 
-      continue;   // We only care about add instructions
-
-    BinaryOperator *Add = cast<BinaryOperator>(Inst);
-
-    // Make sure the array is the first operand of the add expression...
-    if (Add->getOperand(0) != V)
-      Add->swapOperands();
-
-    // Get the amount added to the pointer value...
-    Value *AddAmount = Add->getOperand(1);
-
-    
-  }
-  return false;
-}
-
-
-// Peephole Malloc instructions: we take a look at the use chain of the
-// malloc instruction, and try to find out if the following conditions hold:
-//   1. The malloc is of the form: 'malloc [sbyte], uint <constant>'
-//   2. The only users of the malloc are cast & add instructions
-//   3. Of the cast instructions, there is only one destination pointer type
-//      [RTy] where the size of the pointed to object is equal to the number
-//      of bytes allocated.
-//
-// If these conditions hold, we convert the malloc to allocate an [RTy]
-// element.  This should be extended in the future to handle arrays. TODO
-//
-static bool PeepholeMallocInst(BasicBlock *BB, BasicBlock::iterator &BI) {
-  MallocInst *MI = cast<MallocInst>(*BI);
-  if (!MI->isArrayAllocation()) return false;    // No array allocation?
-
-  ConstPoolUInt *Amt = dyn_cast<ConstPoolUInt>(MI->getArraySize());
-  if (Amt == 0 || MI->getAllocatedType() != ArrayType::get(Type::SByteTy))
-    return false;
-
-  // Get the number of bytes allocated...
-  unsigned Size = Amt->getValue();
-  const Type *ResultTy = 0;
-
-  // Loop over all of the uses of the malloc instruction, inspecting casts.
-  for (Value::use_iterator I = MI->use_begin(), E = MI->use_end();
-       I != E; ++I) {
-    if (CastInst *CI = dyn_cast<CastInst>(*I)) {
-        //cerr << "\t" << CI;
-    
-      // We only work on casts to pointer types for sure, be conservative
-      if (!isa<PointerType>(CI->getType())) {
-        cerr << "Found cast of malloc value to non pointer type:\n" << CI;
-        return false;
-      }
-
-      const Type *DestTy = cast<PointerType>(CI->getType())->getValueType();
-      if (isa<ArrayType>(DestTy)) {
-        cerr << "Avoided malloc conversion because of type: " << DestTy
-             << " TODO.\n";
-        return false;
-      }
-      if (TD.getTypeSize(DestTy) == Size && DestTy != ResultTy) {
-        // Does the size of the allocated type match the number of bytes
-        // allocated?
-        //
-        if (ResultTy == 0) {
-          ResultTy = DestTy;   // Keep note of this for future uses...
-        } else {
-          // It's overdefined!  We don't know which type to convert to!
-          return false;
-        }
-      }
-    }
-  }
-
-  // If we get this far, we have either found, or not, a type that is cast to
-  // that is of the same size as the malloc instruction.
-  if (!ResultTy) return false;
-
-  // Now we check to see if we can convert the return value of malloc to the
-  // specified pointer type.  All this is moot if we can't.
-  //
-  ValueTypeCache ConvertedTypes;
-  if (RetValConvertableToType(MI, PointerType::get(ResultTy), ConvertedTypes)) {
-    // Yup, it's convertable, do the transformation now!
-    PRINT_PEEPHOLE1("mall-refine:in ", MI);
-
-    // Create a new malloc instruction, and insert it into the method...
-    MallocInst *NewMI = new MallocInst(PointerType::get(ResultTy));
-    NewMI->setName(MI->getName());
-    MI->setName("");
-    BI = BB->getInstList().insert(BI, NewMI)+1;
-
-    // Create a new cast instruction to cast it to the old type...
-    CastInst *NewCI = new CastInst(NewMI, MI->getType());
-    BB->getInstList().insert(BI, NewCI);
-
-    // Move all users of the old malloc instruction over to use the new cast...
-    MI->replaceAllUsesWith(NewCI);
-
-    ValueMapCache ValueMap;
-    ConvertUsersType(NewCI, NewMI, ValueMap);  // This will delete MI!
-        
-    BI = BB->begin();  // Rescan basic block.  BI might be invalidated.
-    PRINT_PEEPHOLE1("mall-refine:out", NewMI);
-    return true;
-  }
-  return false;
-}
-
-
 
 // Peephole optimize the following instructions:
 // %t1 = cast ulong <const int> to {<...>} *
@@ -288,172 +66,41 @@ static bool PeepholeMallocInst(BasicBlock *BB, BasicBlock::iterator &BI) {
 //
 static bool PeepholeOptimizeAddCast(BasicBlock *BB, BasicBlock::iterator &BI,
                                     Value *AddOp1, CastInst *AddOp2) {
-  Value            *OffsetVal = AddOp2->getOperand(0);
-  Value            *SrcPtr;  // Of type pointer to struct...
-  const StructType *StructTy;
+  const CompositeType *CompTy;
+  Value *OffsetVal = AddOp2->getOperand(0);
+  Value *SrcPtr;  // Of type pointer to struct...
 
-  if ((StructTy = getPointedToStruct(AddOp1->getType()))) {
+  if ((CompTy = getPointedToComposite(AddOp1->getType()))) {
     SrcPtr = AddOp1;                      // Handle the first case...
   } else if (CastInst *AddOp1c = dyn_cast<CastInst>(AddOp1)) {
     SrcPtr = AddOp1c->getOperand(0);      // Handle the second case...
-    StructTy = getPointedToStruct(SrcPtr->getType());
+    CompTy = getPointedToComposite(SrcPtr->getType());
   }
 
   // Only proceed if we have detected all of our conditions successfully...
-  if (!StructTy || !SrcPtr || !OffsetVal->getType()->isIntegral())
+  if (!CompTy || !SrcPtr || !OffsetVal->getType()->isIntegral())
     return false;
 
-  // See if the cast is of an integer expression that is either a constant,
-  // or a value scaled by some amount with a possible offset.
-  //
-  analysis::ExprType Expr = analysis::ClassifyExpression(OffsetVal);
-  unsigned         Offset = 0, Scale = 1;
-
-  // The expression must either be a constant, or a scaled index to be useful
-  if (!Expr.Offset && !Expr.Scale)
-    return false;
-
-  // Get the offset value if it exists...
-  if (Expr.Offset) {
-    if (ConstPoolSInt *CPSI = dyn_cast<ConstPoolSInt>(Expr.Offset))
-      Offset = (unsigned)CPSI->getValue();
-    else {
-      ConstPoolUInt *CPUI = cast<ConstPoolUInt>(Expr.Offset);
-      Offset = (unsigned)CPUI->getValue();
-    }
-    assert(Offset != 0 && "Expression analysis failure!");
-  }
-
-  // Get the scale value if it exists...
-  if (Expr.Scale) {
-    if (ConstPoolSInt *CPSI = dyn_cast<ConstPoolSInt>(Expr.Scale))
-      Scale = (unsigned)CPSI->getValue();
-    else {
-      ConstPoolUInt *CPUI = cast<ConstPoolUInt>(Expr.Scale);
-      Scale = (unsigned)CPUI->getValue();
-    }
-    assert(Scale != 1 && "Expression analysis failure!");
-  }
-  
-  // Check to make sure the offset is not negative or really large, outside the
-  // scope of this structure...
-  //
-  if (Offset >= TD.getTypeSize(StructTy))
-    return false;
+  vector<Value*> Indices;
+  if (!ConvertableToGEP(SrcPtr->getType(), OffsetVal, Indices, &BI))
+    return false;  // Not convertable... perhaps next time
 
-  const StructLayout *SL = TD.getStructLayout(StructTy);
-  vector<ConstPoolVal*> Offsets;
-  unsigned ActualOffset = Offset;
-  const Type *ElTy = getStructOffsetType(StructTy, ActualOffset, Offsets);
-  
-  if (getPointedToStruct(AddOp1->getType())) {  // case 1
+  if (getPointedToComposite(AddOp1->getType())) {  // case 1
     PRINT_PEEPHOLE2("add-to-gep1:in", AddOp2, *BI);
   } else {
     PRINT_PEEPHOLE3("add-to-gep2:in", AddOp1, AddOp2, *BI);
   }
 
-  GetElementPtrInst *GEP = new GetElementPtrInst(SrcPtr, Offsets);
-  //AddOp2->getName());
+  GetElementPtrInst *GEP = new GetElementPtrInst(SrcPtr, Indices,
+                                                 AddOp2->getName());
   BI = BB->getInstList().insert(BI, GEP)+1;
-  
-  Instruction *AddrSrc = GEP;
-  
-  if (const ArrayType *AT = dyn_cast<ArrayType>(ElTy)) {
-    assert((Scale == 1 || Offset == ActualOffset) &&
-           "Cannot handle scaled expression and unused offset in the same "
-           "instruction until after GEP array works!");
-
-    // Check to see if we have bottomed out INSIDE of an array reference..
-    //
-    if (Offset != ActualOffset) {
-      // Insert a cast of the "rest" of the offset to the appropriate
-      // pointer type.
-      CastInst *OffInst =
-        new CastInst(ConstPoolUInt::get(Type::ULongTy, 
-                                        Offset-ActualOffset),
-                     GEP->getType());
-      BI = BB->getInstList().insert(BI, OffInst)+1;
-      
-      // Now insert an ADD to actually adjust the pointer...
-      Instruction *AddInst =
-        BinaryOperator::create(Instruction::Add, GEP, OffInst);
-      BI = BB->getInstList().insert(BI, AddInst)+1;
 
-      PRINT_PEEPHOLE2("add-to-gep:out1", OffInst, AddInst);
-      
-      AddrSrc = AddInst;
-    } else if (Scale != 1) {
-      // If the scale factor occurs, then this means that there is an index into
-      // this element of the array.  Check to make sure the scale factor is the
-      // same as the size of the datatype that we are dealing with.
-      //
-      assert(Scale == TD.getTypeSize(AT->getElementType()) && 
-             "Scaling by something other than the array element size!!");
-      
-      // TODO: In the future, we will not want to cast the index and scale to
-      // pointer types first.  We will want to create a GEP directly here.
-
-      // Now we must actually perform the scaling operation to get an
-      // appropriate value to add in... but the scale has to be done in the
-      // appropriate destination pointer type, so cast the index value now.
-      //
-      // Cast the base index pointer
-      CastInst *IdxValue = new CastInst(Expr.Var, GEP->getType());
-      BI = BB->getInstList().insert(BI, IdxValue)+1;
-
-      // Case the scale amount as well...
-      CastInst *ScaleAmt =
-        new CastInst(ConstPoolUInt::get(Type::ULongTy, Scale), GEP->getType());
-      BI = BB->getInstList().insert(BI, ScaleAmt)+1;
-
-      // Insert the multiply now.  Make sure to make the constant the second arg
-      Instruction *ScaledVal =
-        BinaryOperator::create(Instruction::Mul, IdxValue, ScaleAmt);
-      BI = BB->getInstList().insert(BI, ScaledVal)+1;
-
-      // Now insert an ADD to actually adjust the pointer...
-      Instruction *AddInst =
-        BinaryOperator::create(Instruction::Add, GEP, ScaledVal);
-      BI = BB->getInstList().insert(BI, AddInst)+1;
-
-      PRINT_PEEPHOLE4("add-to-gep:out1", IdxValue, ScaleAmt, ScaledVal, 
-                      AddInst);
-      AddrSrc = AddInst;
-    }
-    
-    // Insert a cast of the pointer to array of X to be a pointer to the
-    // element of the array.
-    //
-    // Insert a cast of the "rest" of the offset to the appropriate
-    // pointer type.
-    CastInst *ACI = new CastInst(AddrSrc, AT->getElementType());
-    BI = BB->getInstList().insert(BI, ACI)+1;
-    AddrSrc = ACI;
-    
-  } else {
-    assert(Offset == ActualOffset && "GEP to middle of non array!");
-    assert(Scale == 1 && "Scale factor for expr that is not an array idx!");
-  }
-  
-  Instruction *NCI = new CastInst(AddrSrc, AddOp1->getType());
+  Instruction *NCI = new CastInst(GEP, AddOp1->getType());
   ReplaceInstWithInst(BB->getInstList(), BI, NCI);
   PRINT_PEEPHOLE2("add-to-gep:out", GEP, NCI);
   return true;
 }
 
-// Peephole optimize the following instructions:
-//   %t1 = cast int (uint) * %reg111 to uint (...) *
-//   %t2 = call uint (...) * %cast111( uint %key )
-//
-// Into: %t3 = call int (uint) * %reg111( uint %key )
-//       %t2 = cast int %t3 to uint
-//
-static bool PeepholeCallInst(BasicBlock *BB, BasicBlock::iterator &BI) {
-  CallInst *CI = cast<CallInst>(*BI);
-  return false;
-}
-
-
 static bool PeepholeOptimize(BasicBlock *BB, BasicBlock::iterator &BI) {
   Instruction *I = *BI;
 
@@ -502,14 +149,14 @@ static bool PeepholeOptimize(BasicBlock *BB, BasicBlock::iterator &BI) {
     // specific type of the operands to do it's job.
     if (!isReinterpretingCast(CI)) {
       ValueTypeCache ConvertedTypes;
-      if (RetValConvertableToType(CI, Src->getType(), ConvertedTypes)) {
-        PRINT_PEEPHOLE2("CAST-DEST-EXPR-CONV:in ", CI, Src);
+      if (ValueConvertableToType(CI, Src->getType(), ConvertedTypes)) {
+        PRINT_PEEPHOLE2("CAST-DEST-EXPR-CONV:in ", Src, CI);
 
 #ifdef DEBUG_PEEPHOLE_INSTS
         cerr << "\nCONVERTING EXPR TYPE:\n";
 #endif
         ValueMapCache ValueMap;
-        ConvertUsersType(CI, Src, ValueMap);  // This will delete CI!
+        ConvertValueToNewType(CI, Src, ValueMap);  // This will delete CI!
 
         BI = BB->begin();  // Rescan basic block.  BI might be invalidated.
         PRINT_PEEPHOLE1("CAST-DEST-EXPR-CONV:out", Src);
@@ -520,7 +167,7 @@ static bool PeepholeOptimize(BasicBlock *BB, BasicBlock::iterator &BI) {
       } else {
         ConvertedTypes.clear();
         if (ExpressionConvertableToType(Src, DestTy, ConvertedTypes)) {
-          PRINT_PEEPHOLE2("CAST-SRC-EXPR-CONV:in ", CI, Src);
+          PRINT_PEEPHOLE2("CAST-SRC-EXPR-CONV:in ", Src, CI);
           
 #ifdef DEBUG_PEEPHOLE_INSTS
           cerr << "\nCONVERTING SRC EXPR TYPE:\n";
@@ -552,7 +199,7 @@ static bool PeepholeOptimize(BasicBlock *BB, BasicBlock::iterator &BI) {
     //       %t1 = cast <eltype> * %t1 to <ty> *
     //
 #if 1
-    if (const StructType *STy = getPointedToStruct(Src->getType()))
+    if (const CompositeType *CTy = getPointedToComposite(Src->getType()))
       if (const PointerType *DestPTy = dyn_cast<PointerType>(DestTy)) {
 
         // Loop over uses of the cast, checking for add instructions.  If an add
@@ -574,24 +221,34 @@ static bool PeepholeOptimize(BasicBlock *BB, BasicBlock::iterator &BI) {
         if (!HasAddUse) {
           const Type *DestPointedTy = DestPTy->getValueType();
           unsigned Depth = 1;
-          const StructType *CurSTy = STy;
+          const CompositeType *CurCTy = CTy;
           const Type *ElTy = 0;
-          while (CurSTy) {
-            
-            // Check for a zero element struct type... if we have one, bail.
-            if (CurSTy->getElementTypes().size() == 0) break;
+
+          // Build the index vector, full of all zeros
+          vector<Value*> Indices;
+
+          while (CurCTy) {
+            if (const StructType *CurSTy = dyn_cast<StructType>(CurCTy)) {
+              // Check for a zero element struct type... if we have one, bail.
+              if (CurSTy->getElementTypes().size() == 0) break;
             
-            // Grab the first element of the struct type, which must lie at
-            // offset zero in the struct.
-            //
-            ElTy = CurSTy->getElementTypes()[0];
+              // Grab the first element of the struct type, which must lie at
+              // offset zero in the struct.
+              //
+              ElTy = CurSTy->getElementTypes()[0];
+            } else {
+              ElTy = cast<ArrayType>(CurCTy)->getElementType();
+            }
+
+            // Insert a zero to index through this type...
+            Indices.push_back(ConstPoolUInt::get(CurCTy->getIndexType(), 0));
 
             // Did we find what we're looking for?
-            if (losslessCastableTypes(ElTy, DestPointedTy)) break;
+            if (ElTy->isLosslesslyConvertableTo(DestPointedTy)) break;
             
             // Nope, go a level deeper.
             ++Depth;
-            CurSTy = dyn_cast<StructType>(ElTy);
+            CurCTy = dyn_cast<CompositeType>(ElTy);
             ElTy = 0;
           }
           
@@ -599,10 +256,6 @@ static bool PeepholeOptimize(BasicBlock *BB, BasicBlock::iterator &BI) {
           if (ElTy) {
             PRINT_PEEPHOLE1("cast-for-first:in", CI);
 
-            // Build the index vector, full of all zeros
-            vector<ConstPoolVal *> Indices(Depth,
-                                           ConstPoolUInt::get(Type::UByteTy,0));
-
             // Insert the new T cast instruction... stealing old T's name
             GetElementPtrInst *GEP = new GetElementPtrInst(Src, Indices,
                                                            CI->getName());
@@ -622,12 +275,6 @@ static bool PeepholeOptimize(BasicBlock *BB, BasicBlock::iterator &BI) {
 #endif
 
 #if 1
-  } else if (MallocInst *MI = dyn_cast<MallocInst>(I)) {
-    if (PeepholeMallocInst(BB, BI)) return true;
-
-  } else if (CallInst *CI = dyn_cast<CallInst>(I)) {
-    if (PeepholeCallInst(BB, BI)) return true;
-
   } else if (StoreInst *SI = dyn_cast<StoreInst>(I)) {
     Value *Val     = SI->getOperand(0);
     Value *Pointer = SI->getPointerOperand();
@@ -642,9 +289,8 @@ static bool PeepholeOptimize(BasicBlock *BB, BasicBlock::iterator &BI) {
       // Append any indices that the store instruction has onto the end of the
       // ones that the GEP is carrying...
       //
-      vector<ConstPoolVal*> Indices(GEP->getIndices());
-      Indices.insert(Indices.end(), SI->getIndices().begin(),
-                     SI->getIndices().end());
+      vector<Value*> Indices(GEP->copyIndices());
+      Indices.insert(Indices.end(), SI->idx_begin(), SI->idx_end());
 
       PRINT_PEEPHOLE2("gep-store:in", GEP, SI);
       ReplaceInstWithInst(BB->getInstList(), BI,
@@ -665,8 +311,8 @@ static bool PeepholeOptimize(BasicBlock *BB, BasicBlock::iterator &BI) {
     if (CastInst *CI = dyn_cast<CastInst>(Pointer))
       if (Value *CastSrc = CI->getOperand(0)) // CSPT = CastSrcPointerType
         if (PointerType *CSPT = dyn_cast<PointerType>(CastSrc->getType()))
-          if (losslessCastableTypes(Val->getType(), // convertable types!
-                                    CSPT->getValueType()) &&
+          // convertable types?
+          if (Val->getType()->isLosslesslyConvertableTo(CSPT->getValueType()) &&
               !SI->hasIndices()) {      // No subscripts yet!
             PRINT_PEEPHOLE3("st-src-cast:in ", Pointer, Val, SI);
 
@@ -697,9 +343,8 @@ static bool PeepholeOptimize(BasicBlock *BB, BasicBlock::iterator &BI) {
       // Append any indices that the load instruction has onto the end of the
       // ones that the GEP is carrying...
       //
-      vector<ConstPoolVal*> Indices(GEP->getIndices());
-      Indices.insert(Indices.end(), LI->getIndices().begin(),
-                     LI->getIndices().end());
+      vector<Value*> Indices(GEP->copyIndices());
+      Indices.insert(Indices.end(), LI->idx_begin(), LI->idx_end());
 
       PRINT_PEEPHOLE2("gep-load:in", GEP, LI);
       ReplaceInstWithInst(BB->getInstList(), BI,
@@ -729,7 +374,8 @@ static bool PeepholeOptimize(BasicBlock *BB, BasicBlock::iterator &BI) {
       const Type *ElTy = SrcTy ? SrcTy->getValueType() : 0;
 
       // Make sure that nothing will be lost in the new cast...
-      if (SrcTy && losslessCastableTypes(ElTy, LI->getType())) {
+      if (!LI->hasIndices() && SrcTy &&
+          ElTy->isLosslesslyConvertableTo(LI->getType())) {
         PRINT_PEEPHOLE2("CL-LoadCast:in ", CI, LI);
 
         string CName = CI->getName(); CI->setName("");
@@ -785,37 +431,143 @@ static bool DoRaisePass(Method *M) {
 }
 
 
+
+
+// DoInsertArrayCast - If the argument value has a pointer type, and if the
+// argument value is used as an array, insert a cast before the specified 
+// basic block iterator that casts the value to an array pointer.  Return the
+// new cast instruction (in the CastResult var), or null if no cast is inserted.
+//
+static bool DoInsertArrayCast(Value *V, BasicBlock *BB,
+			      BasicBlock::iterator InsertBefore) {
+  const PointerType *ThePtrType = dyn_cast<PointerType>(V->getType());
+  if (!ThePtrType) return false;
+
+  const Type *ElTy = ThePtrType->getValueType();
+  if (isa<MethodType>(ElTy) || isa<ArrayType>(ElTy)) return false;
+
+  unsigned ElementSize = TD.getTypeSize(ElTy);
+  bool InsertCast = false;
+
+  for (Value::use_iterator I = V->use_begin(), E = V->use_end(); I != E; ++I) {
+    Instruction *Inst = cast<Instruction>(*I);
+    switch (Inst->getOpcode()) {
+    case Instruction::Cast:          // There is already a cast instruction!
+      if (const PointerType *PT = dyn_cast<const PointerType>(Inst->getType()))
+	if (const ArrayType *AT = dyn_cast<const ArrayType>(PT->getValueType()))
+	  if (AT->getElementType() == ThePtrType->getValueType()) {
+	    // Cast already exists! Don't mess around with it.
+	    return false;       // No changes made to program though...
+	  }
+      break;
+    case Instruction::Add: {         // Analyze pointer arithmetic...
+      Value *OtherOp = Inst->getOperand(Inst->getOperand(0) == V);
+      analysis::ExprType Expr = analysis::ClassifyExpression(OtherOp);
+
+      // This looks like array addressing iff:
+      //   A. The constant of the index is larger than the size of the element
+      //      type.
+      //   B. The scale factor is >= the size of the type.
+      //
+      if (Expr.Offset && getConstantValue(Expr.Offset) >= (int)ElementSize) // A
+        InsertCast = true;
+
+      if (Expr.Scale && getConstantValue(Expr.Scale) >= (int)ElementSize) // B
+        InsertCast = true;
+
+      break;
+    }
+    default: break;                  // Not an interesting use...
+    }
+  }
+
+  if (!InsertCast) return false;  // There is no reason to insert a cast!
+
+  // Calculate the destination pointer type
+  const PointerType *DestTy = PointerType::get(ArrayType::get(ElTy));
+
+  // Check to make sure that all uses of the value can be converted over to use
+  // the newly typed value.
+  //
+  ValueTypeCache ConvertedTypes;
+  if (!ValueConvertableToType(V, DestTy, ConvertedTypes)) {
+    cerr << "FAILED to convert types of values for " << V << "\n";
+    ConvertedTypes.clear();
+    ValueConvertableToType(V, DestTy, ConvertedTypes);
+    return false;
+  }
+  ConvertedTypes.clear();
+
+  // Insert a cast!
+  CastInst *TheCast = 
+    new CastInst(ConstPoolVal::getNullConstant(V->getType()), DestTy,
+                 V->getName());
+  BB->getInstList().insert(InsertBefore, TheCast);
+
+  cerr << "Inserting cast for " << V << endl;
+
+  // Convert users of the old value over to use the cast result...
+  ValueMapCache VMC;
+  ConvertValueToNewType(V, TheCast, VMC);
+
+  // The cast is the only thing that is allowed to reference the value...
+  TheCast->setOperand(0, V);
+
+  cerr << "Inserted ptr-array cast: " << TheCast;
+  return true;            // Made a change!
+}
+
+
+// DoInsertArrayCasts - Loop over all "incoming" values in the specified method,
+// inserting a cast for pointer values that are used as arrays. For our
+// purposes, an incoming value is considered to be either a value that is 
+// either a method parameter, or a pointer returned from a function call.
+//
+static bool DoInsertArrayCasts(Method *M) {
+  assert(!M->isExternal() && "Can't handle external methods!");
+
+  // Insert casts for all arguments to the function...
+  bool Changed = false;
+  BasicBlock *CurBB = M->front();
+
+  for (Method::ArgumentListType::iterator AI = M->getArgumentList().begin(), 
+	 AE = M->getArgumentList().end(); AI != AE; ++AI) {
+
+    Changed |= DoInsertArrayCast(*AI, CurBB, CurBB->begin());
+  }
+
+  // TODO: insert casts for alloca, malloc, and function call results.  Also, 
+  // look for pointers that already have casts, to add to the map.
+
+  return Changed;
+}
+
+
+
+
 // RaisePointerReferences::doit - Raise a method representation to a higher
 // level.
 //
 bool RaisePointerReferences::doit(Method *M) {
   if (M->isExternal()) return false;
-  bool Changed = false;
 
 #ifdef DEBUG_PEEPHOLE_INSTS
   cerr << "\n\n\nStarting to work on Method '" << M->getName() << "'\n";
 #endif
 
-  while (DoRaisePass(M)) Changed = true;
-
-#if 0
-  // PtrCasts - Keep a mapping between the pointer values (the key of the 
-  // map), and the cast to array pointer (the value) in this map.  This is
-  // used when converting pointer math into array addressing.
-  // 
-  map<Value*, CastInst*> PtrCasts;
-
-  // Insert casts for all incoming pointer values.  Keep track of those casts
-  // and the identified incoming values in the PtrCasts map.
+  // Insert casts for all incoming pointer pointer values that are treated as
+  // arrays...
   //
-  Changed |= DoInsertArrayCasts(M, PtrCasts);
+  bool Changed = false, LocalChange;
+  do {
+    LocalChange = DoInsertArrayCasts(M);
 
-  // Loop over each incoming pointer variable, replacing indexing arithmetic
-  // with getelementptr calls.
-  //
-  Changed |= reduce_apply_bool(PtrCasts.begin(), PtrCasts.end(), 
-                               ptr_fun(DoEliminatePointerArithmetic));
-#endif
+    // Iterate over the method, refining it, until it converges on a stable
+    // state
+    while (DoRaisePass(M)) LocalChange = true;
+    Changed |= LocalChange;
+
+  } while (LocalChange);
 
   return Changed;
 }