mirror of
https://github.com/c64scene-ar/llvm-6502.git
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git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@1140 91177308-0d34-0410-b5e6-96231b3b80d8
629 lines
23 KiB
C++
629 lines
23 KiB
C++
//===- LevelRaise.cpp - Code to change LLVM to higher level -----------------=//
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//
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// This file implements the 'raising' part of the LevelChange API. This is
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// useful because, in general, it makes the LLVM code terser and easier to
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// analyze. Note that it is good to run DCE after doing this transformation.
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//
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// Eliminate silly things in the source that do not effect the level, but do
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// clean up the code:
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// * Casts of casts
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// - getelementptr/load & getelementptr/store are folded into a direct
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// load or store
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// - Convert this code (for both alloca and malloc):
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// %reg110 = shl uint %n, ubyte 2 ;;<uint>
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// %reg108 = alloca ubyte, uint %reg110 ;;<ubyte*>
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// %cast76 = cast ubyte* %reg108 to uint* ;;<uint*>
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// To: %cast76 = alloca uint, uint %n
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// Convert explicit addressing to use getelementptr instruction where possible
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// - ...
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//
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// Convert explicit addressing on pointers to use getelementptr instruction.
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// - If a pointer is used by arithmetic operation, insert an array casted
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// version into the source program, only for the following pointer types:
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// * Method argument pointers
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// - Pointers returned by alloca or malloc
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// - Pointers returned by function calls
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// - If a pointer is indexed with a value scaled by a constant size equal
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// to the element size of the array, the expression is replaced with a
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// getelementptr instruction.
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//
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//===----------------------------------------------------------------------===//
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#include "llvm/Transforms/LevelChange.h"
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#include "TransformInternals.h"
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#include "llvm/Method.h"
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#include "llvm/Support/STLExtras.h"
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#include "llvm/iOther.h"
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#include "llvm/iMemory.h"
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#include "llvm/ConstPoolVals.h"
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#include "llvm/Optimizations/ConstantHandling.h"
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#include "llvm/Optimizations/DCE.h"
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#include <algorithm>
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#include "llvm/Assembly/Writer.h"
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//#define DEBUG_PEEPHOLE_INSTS 1
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#ifdef DEBUG_PEEPHOLE_INSTS
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#define PRINT_PEEPHOLE(ID, NUM, I) \
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cerr << "Inst P/H " << ID << "[" << NUM << "] " << I;
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#else
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#define PRINT_PEEPHOLE(ID, NUM, I)
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#endif
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#define PRINT_PEEPHOLE1(ID, I1) do { PRINT_PEEPHOLE(ID, 0, I1); } while (0)
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#define PRINT_PEEPHOLE2(ID, I1, I2) \
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do { PRINT_PEEPHOLE(ID, 0, I1); PRINT_PEEPHOLE(ID, 1, I2); } while (0)
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#define PRINT_PEEPHOLE3(ID, I1, I2, I3) \
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do { PRINT_PEEPHOLE(ID, 0, I1); PRINT_PEEPHOLE(ID, 1, I2); \
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PRINT_PEEPHOLE(ID, 2, I3); } while (0)
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// isReinterpretingCast - Return true if the cast instruction specified will
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// cause the operand to be "reinterpreted". A value is reinterpreted if the
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// cast instruction would cause the underlying bits to change.
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//
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static inline bool isReinterpretingCast(const CastInst *CI) {
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return !losslessCastableTypes(CI->getOperand(0)->getType(), CI->getType());
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}
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// getPointedToStruct - If the argument is a pointer type, and the pointed to
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// value is a struct type, return the struct type, else return null.
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//
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static const StructType *getPointedToStruct(const Type *Ty) {
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const PointerType *PT = dyn_cast<PointerType>(Ty);
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return PT ? dyn_cast<StructType>(PT->getValueType()) : 0;
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}
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// getStructOffsetType - Return a vector of offsets that are to be used to index
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// into the specified struct type to get as close as possible to index as we
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// can. Note that it is possible that we cannot get exactly to Offset, in which
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// case we update offset to be the offset we actually obtained. The resultant
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// leaf type is returned.
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//
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static const Type *getStructOffsetType(const Type *Ty, unsigned &Offset,
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vector<ConstPoolVal*> &Offsets) {
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if (!isa<StructType>(Ty)) {
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Offset = 0; // Return the offset that we were able to acheive
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return Ty; // Return the leaf type
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}
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assert(Offset < TD.getTypeSize(Ty) && "Offset not in struct!");
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const StructType *STy = cast<StructType>(Ty);
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const StructLayout *SL = TD.getStructLayout(STy);
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// This loop terminates always on a 0 <= i < MemberOffsets.size()
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unsigned i;
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for (i = 0; i < SL->MemberOffsets.size()-1; ++i)
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if (Offset >= SL->MemberOffsets[i] && Offset < SL->MemberOffsets[i+1])
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break;
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assert(Offset >= SL->MemberOffsets[i] &&
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(i == SL->MemberOffsets.size()-1 || Offset < SL->MemberOffsets[i+1]));
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// Make sure to save the current index...
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Offsets.push_back(ConstPoolUInt::get(Type::UByteTy, i));
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unsigned SubOffs = Offset - SL->MemberOffsets[i];
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const Type *LeafTy = getStructOffsetType(STy->getElementTypes()[i], SubOffs,
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Offsets);
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Offset = SL->MemberOffsets[i] + SubOffs;
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return LeafTy;
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}
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// DoInsertArrayCast - If the argument value has a pointer type, and if the
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// argument value is used as an array, insert a cast before the specified
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// basic block iterator that casts the value to an array pointer. Return the
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// new cast instruction (in the CastResult var), or null if no cast is inserted.
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//
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static bool DoInsertArrayCast(Method *CurMeth, Value *V, BasicBlock *BB,
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BasicBlock::iterator &InsertBefore,
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CastInst *&CastResult) {
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const PointerType *ThePtrType = dyn_cast<PointerType>(V->getType());
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if (!ThePtrType) return false;
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bool InsertCast = false;
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for (Value::use_iterator I = V->use_begin(), E = V->use_end(); I != E; ++I) {
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Instruction *Inst = cast<Instruction>(*I);
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switch (Inst->getOpcode()) {
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default: break; // Not an interesting use...
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case Instruction::Add: // It's being used as an array index!
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//case Instruction::Sub:
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InsertCast = true;
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break;
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case Instruction::Cast: // There is already a cast instruction!
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if (const PointerType *PT = dyn_cast<const PointerType>(Inst->getType()))
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if (const ArrayType *AT = dyn_cast<const ArrayType>(PT->getValueType()))
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if (AT->getElementType() == ThePtrType->getValueType()) {
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// Cast already exists! Return the existing one!
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CastResult = cast<CastInst>(Inst);
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return false; // No changes made to program though...
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}
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break;
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}
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}
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if (!InsertCast) return false; // There is no reason to insert a cast!
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// Insert a cast!
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const Type *ElTy = ThePtrType->getValueType();
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const PointerType *DestTy = PointerType::get(ArrayType::get(ElTy));
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CastResult = new CastInst(V, DestTy);
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BB->getInstList().insert(InsertBefore, CastResult);
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//cerr << "Inserted cast: " << CastResult;
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return true; // Made a change!
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}
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// DoInsertArrayCasts - Loop over all "incoming" values in the specified method,
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// inserting a cast for pointer values that are used as arrays. For our
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// purposes, an incoming value is considered to be either a value that is
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// either a method parameter, a value created by alloca or malloc, or a value
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// returned from a function call. All casts are kept attached to their original
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// values through the PtrCasts map.
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//
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static bool DoInsertArrayCasts(Method *M, map<Value*, CastInst*> &PtrCasts) {
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assert(!M->isExternal() && "Can't handle external methods!");
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// Insert casts for all arguments to the function...
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bool Changed = false;
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BasicBlock *CurBB = M->front();
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BasicBlock::iterator It = CurBB->begin();
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for (Method::ArgumentListType::iterator AI = M->getArgumentList().begin(),
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AE = M->getArgumentList().end(); AI != AE; ++AI) {
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CastInst *TheCast = 0;
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if (DoInsertArrayCast(M, *AI, CurBB, It, TheCast)) {
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It = CurBB->begin(); // We might have just invalidated the iterator!
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Changed = true; // Yes we made a change
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++It; // Insert next cast AFTER this one...
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}
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if (TheCast) // Is there a cast associated with this value?
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PtrCasts[*AI] = TheCast; // Yes, add it to the map...
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}
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// TODO: insert casts for alloca, malloc, and function call results. Also,
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// look for pointers that already have casts, to add to the map.
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return Changed;
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}
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// DoElminatePointerArithmetic - Loop over each incoming pointer variable,
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// replacing indexing arithmetic with getelementptr calls.
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//
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static bool DoEliminatePointerArithmetic(const pair<Value*, CastInst*> &Val) {
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Value *V = Val.first; // The original pointer
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CastInst *CV = Val.second; // The array casted version of the pointer...
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for (Value::use_iterator I = V->use_begin(), E = V->use_end(); I != E; ++I) {
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Instruction *Inst = cast<Instruction>(*I);
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if (Inst->getOpcode() != Instruction::Add)
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continue; // We only care about add instructions
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BinaryOperator *Add = cast<BinaryOperator>(Inst);
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// Make sure the array is the first operand of the add expression...
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if (Add->getOperand(0) != V)
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Add->swapOperands();
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// Get the amount added to the pointer value...
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Value *AddAmount = Add->getOperand(1);
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}
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return false;
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}
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// Peephole Malloc instructions: we take a look at the use chain of the
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// malloc instruction, and try to find out if the following conditions hold:
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// 1. The malloc is of the form: 'malloc [sbyte], uint <constant>'
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// 2. The only users of the malloc are cast & add instructions
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// 3. Of the cast instructions, there is only one destination pointer type
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// [RTy] where the size of the pointed to object is equal to the number
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// of bytes allocated.
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//
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// If these conditions hold, we convert the malloc to allocate an [RTy]
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// element. This should be extended in the future to handle arrays. TODO
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//
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static bool PeepholeMallocInst(BasicBlock *BB, BasicBlock::iterator &BI) {
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MallocInst *MI = cast<MallocInst>(*BI);
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if (!MI->isArrayAllocation()) return false; // No array allocation?
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ConstPoolUInt *Amt = dyn_cast<ConstPoolUInt>(MI->getArraySize());
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if (Amt == 0 || MI->getAllocatedType() != ArrayType::get(Type::SByteTy))
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return false;
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// Get the number of bytes allocated...
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unsigned Size = Amt->getValue();
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const Type *ResultTy = 0;
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// Loop over all of the uses of the malloc instruction, inspecting casts.
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for (Value::use_iterator I = MI->use_begin(), E = MI->use_end();
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I != E; ++I) {
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if (!isa<CastInst>(*I) && !isa<BinaryOperator>(*I)) {
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//cerr << "\tnon" << *I;
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return false; // A non cast user?
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}
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if (CastInst *CI = dyn_cast<CastInst>(*I)) {
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//cerr << "\t" << CI;
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// We only work on casts to pointer types for sure, be conservative
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if (!isa<PointerType>(CI->getType())) {
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cerr << "Found cast of malloc value to non pointer type:\n" << CI;
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return false;
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}
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const Type *DestTy = cast<PointerType>(CI->getType())->getValueType();
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if (TD.getTypeSize(DestTy) == Size && DestTy != ResultTy) {
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// Does the size of the allocated type match the number of bytes
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// allocated?
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//
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if (ResultTy == 0) {
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ResultTy = DestTy; // Keep note of this for future uses...
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} else {
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// It's overdefined! We don't know which type to convert to!
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return false;
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}
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}
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}
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}
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// If we get this far, we have either found, or not, a type that is cast to
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// that is of the same size as the malloc instruction.
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if (!ResultTy) return false;
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PRINT_PEEPHOLE1("mall-refine:in ", MI);
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ReplaceInstWithInst(BB->getInstList(), BI,
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MI = new MallocInst(PointerType::get(ResultTy)));
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PRINT_PEEPHOLE1("mall-refine:out", MI);
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return true;
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}
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// Peephole optimize the following instructions:
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// %t1 = cast int (uint) * %reg111 to uint (...) *
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// %t2 = call uint (...) * %cast111( uint %key )
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//
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// Into: %t3 = call int (uint) * %reg111( uint %key )
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// %t2 = cast int %t3 to uint
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//
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static bool PeepholeCallInst(BasicBlock *BB, BasicBlock::iterator &BI) {
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CallInst *CI = cast<CallInst>(*BI);
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return false;
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}
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static bool PeepholeOptimize(BasicBlock *BB, BasicBlock::iterator &BI) {
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Instruction *I = *BI;
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if (CastInst *CI = dyn_cast<CastInst>(I)) {
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Value *Src = CI->getOperand(0);
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Instruction *SrcI = dyn_cast<Instruction>(Src); // Nonnull if instr source
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const Type *DestTy = CI->getType();
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// Peephole optimize the following instruction:
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// %V2 = cast <ty> %V to <ty>
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//
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// Into: <nothing>
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//
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if (DestTy == Src->getType()) { // Check for a cast to same type as src!!
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PRINT_PEEPHOLE1("cast-of-self-ty", CI);
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CI->replaceAllUsesWith(Src);
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if (!Src->hasName() && CI->hasName()) {
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string Name = CI->getName();
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CI->setName("");
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Src->setName(Name, BB->getParent()->getSymbolTable());
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}
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return true;
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}
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// Peephole optimize the following instructions:
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// %tmp = cast <ty> %V to <ty2>
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// %V = cast <ty2> %tmp to <ty3> ; Where ty & ty2 are same size
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//
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// Into: cast <ty> %V to <ty3>
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//
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if (SrcI)
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if (CastInst *CSrc = dyn_cast<CastInst>(SrcI))
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if (isReinterpretingCast(CI) + isReinterpretingCast(CSrc) < 2) {
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// We can only do c-c elimination if, at most, one cast does a
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// reinterpretation of the input data.
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//
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// If legal, make this cast refer the the original casts argument!
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//
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PRINT_PEEPHOLE2("cast-cast:in ", CI, CSrc);
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CI->setOperand(0, CSrc->getOperand(0));
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PRINT_PEEPHOLE1("cast-cast:out", CI);
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return true;
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}
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// Check to see if it's a cast of an instruction that does not depend on the
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// specific type of the operands to do it's job.
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if (!isReinterpretingCast(CI)) {
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ValueTypeCache ConvertedTypes;
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if (RetValConvertableToType(CI, Src->getType(), ConvertedTypes)) {
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PRINT_PEEPHOLE2("CAST-DEST-EXPR-CONV:in ", CI, Src);
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ValueMapCache ValueMap;
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ConvertUsersType(CI, Src, ValueMap); // This will delete CI!
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BI = BB->begin(); // Rescan basic block. BI might be invalidated.
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PRINT_PEEPHOLE1("CAST-DEST-EXPR-CONV:out", I);
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return true;
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}
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}
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// Check to see if we are casting from a structure pointer to a pointer to
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// the first element of the structure... to avoid munching other peepholes,
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// we only let this happen if there are no add uses of the cast.
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//
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// Peephole optimize the following instructions:
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// %t1 = cast {<...>} * %StructPtr to <ty> *
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//
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// Into: %t2 = getelementptr {<...>} * %StructPtr, <0, 0, 0, ...>
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// %t1 = cast <eltype> * %t1 to <ty> *
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//
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if (const StructType *STy = getPointedToStruct(Src->getType()))
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if (const PointerType *DestPTy = dyn_cast<PointerType>(DestTy)) {
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// Loop over uses of the cast, checking for add instructions. If an add
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// exists, this is probably a part of a more complex GEP, so we don't
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// want to mess around with the cast.
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//
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bool HasAddUse = false;
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for (Value::use_iterator I = CI->use_begin(), E = CI->use_end();
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I != E; ++I)
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if (isa<Instruction>(*I) &&
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cast<Instruction>(*I)->getOpcode() == Instruction::Add) {
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HasAddUse = true; break;
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}
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// If it doesn't have an add use, check to see if the dest type is
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// losslessly convertable to one of the types in the start of the struct
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// type.
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//
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if (!HasAddUse) {
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const Type *DestPointedTy = DestPTy->getValueType();
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unsigned Depth = 1;
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const StructType *CurSTy = STy;
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const Type *ElTy = 0;
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while (CurSTy) {
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// Check for a zero element struct type... if we have one, bail.
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if (CurSTy->getElementTypes().size() == 0) break;
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// Grab the first element of the struct type, which must lie at
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// offset zero in the struct.
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//
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ElTy = CurSTy->getElementTypes()[0];
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// Did we find what we're looking for?
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if (losslessCastableTypes(ElTy, DestPointedTy)) break;
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// Nope, go a level deeper.
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++Depth;
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CurSTy = dyn_cast<StructType>(ElTy);
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ElTy = 0;
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}
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// Did we find what we were looking for? If so, do the transformation
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if (ElTy) {
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PRINT_PEEPHOLE1("cast-for-first:in", CI);
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// Build the index vector, full of all zeros
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vector<ConstPoolVal *> Indices(Depth,
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ConstPoolUInt::get(Type::UByteTy,0));
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// Insert the new T cast instruction... stealing old T's name
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GetElementPtrInst *GEP = new GetElementPtrInst(Src, Indices,
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CI->getName());
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CI->setName("");
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BI = BB->getInstList().insert(BI, GEP)+1;
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// Make the old cast instruction reference the new GEP instead of
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// the old src value.
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//
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CI->setOperand(0, GEP);
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PRINT_PEEPHOLE2("cast-for-first:out", GEP, CI);
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return true;
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}
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}
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}
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} else if (MallocInst *MI = dyn_cast<MallocInst>(I)) {
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if (PeepholeMallocInst(BB, BI)) return true;
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} else if (CallInst *CI = dyn_cast<CallInst>(I)) {
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if (PeepholeCallInst(BB, BI)) return true;
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} else if (StoreInst *SI = dyn_cast<StoreInst>(I)) {
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Value *Val = SI->getOperand(0);
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Value *Pointer = SI->getPtrOperand();
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// Peephole optimize the following instructions:
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// %t1 = getelementptr {<...>} * %StructPtr, <element indices>
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|
// store <elementty> %v, <elementty> * %t1
|
|
//
|
|
// Into: store <elementty> %v, {<...>} * %StructPtr, <element indices>
|
|
//
|
|
if (GetElementPtrInst *GEP = dyn_cast<GetElementPtrInst>(Pointer)) {
|
|
PRINT_PEEPHOLE2("gep-store:in", GEP, SI);
|
|
ReplaceInstWithInst(BB->getInstList(), BI,
|
|
SI = new StoreInst(Val, GEP->getPtrOperand(),
|
|
GEP->getIndices()));
|
|
PRINT_PEEPHOLE1("gep-store:out", SI);
|
|
return true;
|
|
}
|
|
|
|
// Peephole optimize the following instructions:
|
|
// %t = cast <T1>* %P to <T2> * ;; If T1 is losslessly convertable to T2
|
|
// store <T2> %V, <T2>* %t
|
|
//
|
|
// Into:
|
|
// %t = cast <T2> %V to <T1>
|
|
// store <T1> %t2, <T1>* %P
|
|
//
|
|
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()) &&
|
|
!SI->hasIndices()) { // No subscripts yet!
|
|
PRINT_PEEPHOLE3("st-src-cast:in ", Pointer, Val, SI);
|
|
|
|
// Insert the new T cast instruction... stealing old T's name
|
|
CastInst *NCI = new CastInst(Val, CSPT->getValueType(),
|
|
CI->getName());
|
|
CI->setName("");
|
|
BI = BB->getInstList().insert(BI, NCI)+1;
|
|
|
|
// Replace the old store with a new one!
|
|
ReplaceInstWithInst(BB->getInstList(), BI,
|
|
SI = new StoreInst(NCI, CastSrc));
|
|
PRINT_PEEPHOLE3("st-src-cast:out", NCI, CastSrc, SI);
|
|
return true;
|
|
}
|
|
|
|
|
|
} else if (LoadInst *LI = dyn_cast<LoadInst>(I)) {
|
|
Value *Pointer = LI->getPtrOperand();
|
|
|
|
// Peephole optimize the following instructions:
|
|
// %t1 = getelementptr {<...>} * %StructPtr, <element indices>
|
|
// %V = load <elementty> * %t1
|
|
//
|
|
// Into: load {<...>} * %StructPtr, <element indices>
|
|
//
|
|
if (GetElementPtrInst *GEP = dyn_cast<GetElementPtrInst>(Pointer)) {
|
|
PRINT_PEEPHOLE2("gep-load:in", GEP, LI);
|
|
ReplaceInstWithInst(BB->getInstList(), BI,
|
|
LI = new LoadInst(GEP->getPtrOperand(),
|
|
GEP->getIndices()));
|
|
PRINT_PEEPHOLE1("gep-load:out", LI);
|
|
return true;
|
|
}
|
|
} else if (I->getOpcode() == Instruction::Add &&
|
|
isa<CastInst>(I->getOperand(1))) {
|
|
|
|
// Peephole optimize the following instructions:
|
|
// %t1 = cast ulong <const int> to {<...>} *
|
|
// %t2 = add {<...>} * %SP, %t1 ;; Constant must be 2nd operand
|
|
//
|
|
// or
|
|
// %t1 = cast {<...>}* %SP to int*
|
|
// %t5 = cast ulong <const int> to int*
|
|
// %t2 = add int* %t1, %t5 ;; int is same size as field
|
|
//
|
|
// Into: %t3 = getelementptr {<...>} * %SP, <element indices>
|
|
// %t2 = cast <eltype> * %t3 to {<...>}*
|
|
//
|
|
Value *AddOp1 = I->getOperand(0);
|
|
CastInst *AddOp2 = cast<CastInst>(I->getOperand(1));
|
|
ConstPoolUInt *OffsetV = dyn_cast<ConstPoolUInt>(AddOp2->getOperand(0));
|
|
unsigned Offset = OffsetV ? OffsetV->getValue() : 0;
|
|
Value *SrcPtr; // Of type pointer to struct...
|
|
const StructType *StructTy;
|
|
|
|
if ((StructTy = getPointedToStruct(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());
|
|
}
|
|
|
|
// Only proceed if we have detected all of our conditions successfully...
|
|
if (Offset && StructTy && SrcPtr && Offset < TD.getTypeSize(StructTy)) {
|
|
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
|
|
PRINT_PEEPHOLE2("add-to-gep1:in", AddOp2, I);
|
|
} else {
|
|
PRINT_PEEPHOLE3("add-to-gep2:in", AddOp1, AddOp2, I);
|
|
}
|
|
|
|
GetElementPtrInst *GEP = new GetElementPtrInst(SrcPtr, Offsets);
|
|
BI = BB->getInstList().insert(BI, GEP)+1;
|
|
|
|
assert(Offset-ActualOffset == 0 &&
|
|
"GEP to middle of element not implemented yet!");
|
|
|
|
ReplaceInstWithInst(BB->getInstList(), BI,
|
|
I = new CastInst(GEP, I->getType()));
|
|
PRINT_PEEPHOLE2("add-to-gep:out", GEP, I);
|
|
return true;
|
|
}
|
|
}
|
|
|
|
return false;
|
|
}
|
|
|
|
|
|
|
|
|
|
static bool DoRaisePass(Method *M) {
|
|
bool Changed = false;
|
|
for (Method::iterator MI = M->begin(), ME = M->end(); MI != ME; ++MI) {
|
|
BasicBlock *BB = *MI;
|
|
BasicBlock::InstListType &BIL = BB->getInstList();
|
|
|
|
for (BasicBlock::iterator BI = BB->begin(); BI != BB->end();) {
|
|
if (opt::DeadCodeElimination::dceInstruction(BIL, BI) ||
|
|
PeepholeOptimize(BB, BI))
|
|
Changed = true;
|
|
else
|
|
++BI;
|
|
}
|
|
}
|
|
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;
|
|
|
|
// 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.
|
|
//
|
|
Changed |= DoInsertArrayCasts(M, PtrCasts);
|
|
|
|
// Loop over each incoming pointer variable, replacing indexing arithmetic
|
|
// with getelementptr calls.
|
|
//
|
|
Changed |= reduce_apply_bool(PtrCasts.begin(), PtrCasts.end(),
|
|
ptr_fun(DoEliminatePointerArithmetic));
|
|
|
|
return Changed;
|
|
}
|