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75747cd9e8
llvm-6502/lib/Transforms/ExprTypeConvert.cpp
Chris Lattner 75747cd9e8 Fix minor bug for shifts 
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@1160 91177308-0d34-0410-b5e6-96231b3b80d8
2001-11-06 21:51:48 +00:00

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//===- ExprTypeConvert.cpp - Code to change an LLVM Expr Type ---------------=//
//
// This file implements the part of level raising that checks to see if it is
// possible to coerce an entire expression tree into a different type. If
// convertable, other routines from this file will do the conversion.
//
//===----------------------------------------------------------------------===//
#include "TransformInternals.h"
#include "llvm/Method.h"
#include "llvm/Support/STLExtras.h"
#include "llvm/iOther.h"
#include "llvm/iMemory.h"
#include "llvm/ConstPoolVals.h"
#include "llvm/Optimizations/ConstantHandling.h"
#include "llvm/Optimizations/DCE.h"
#include <map>
#include <algorithm>
#include "llvm/Assembly/Writer.h"
//#define DEBUG_EXPR_CONVERT 1
static inline const Type *getTy(const Value *V, ValueTypeCache &CT) {
ValueTypeCache::iterator I = CT.find(V);
if (I == CT.end()) return V->getType();
return I->second;
}
static bool OperandConvertableToType(User *U, Value *V, const Type *Ty,
ValueTypeCache &ConvertedTypes);
static void ConvertOperandToType(User *U, Value *OldVal, Value *NewVal,
ValueMapCache &VMC);
// ExpressionConvertableToType - Return true if it is possible
static bool ExpressionConvertableToType(Value *V, const Type *Ty,
ValueTypeCache &CTMap) {
// Expression type must be holdable in a register.
if (!isFirstClassType(Ty))
return false;
ValueTypeCache::iterator CTMI = CTMap.find(V);
if (CTMI != CTMap.end()) return CTMI->second == Ty;
CTMap[V] = Ty;
// Expressions are only convertable if all of the users of the expression can
// have this value converted. This makes use of the map to avoid infinite
// recursion.
//
for (Value::use_iterator I = V->use_begin(), E = V->use_end(); I != E; ++I)
if (!OperandConvertableToType(*I, V, Ty, CTMap))
return false;
Instruction *I = dyn_cast<Instruction>(V);
if (I == 0) {
// It's not an instruction, check to see if it's a constant... all constants
// can be converted to an equivalent value (except pointers, they can't be
// const prop'd in general).
//
if (isa<ConstPoolVal>(V))
if (!isa<PointerType>(V->getType()) && !isa<PointerType>(Ty) &&
!isa<StructType>(Ty) && !isa<ArrayType>(Ty))
return true;
return false; // Otherwise, we can't convert!
}
if (I->getType() == Ty) return false; // Expression already correct type!
switch (I->getOpcode()) {
case Instruction::Cast:
// We can convert the expr if the cast destination type is losslessly
// convertable to the requested type.
return losslessCastableTypes(Ty, I->getType());
case Instruction::Add:
case Instruction::Sub:
return ExpressionConvertableToType(I->getOperand(0), Ty, CTMap) &&
ExpressionConvertableToType(I->getOperand(1), Ty, CTMap);
case Instruction::Shr:
if (Ty->isSigned() != V->getType()->isSigned()) return false;
// FALL THROUGH
case Instruction::Shl:
return ExpressionConvertableToType(I->getOperand(0), Ty, CTMap);
case Instruction::Load: {
LoadInst *LI = cast<LoadInst>(I);
if (LI->hasIndices()) return false;
return ExpressionConvertableToType(LI->getPtrOperand(),
PointerType::get(Ty), CTMap);
}
case Instruction::PHINode: {
PHINode *PN = cast<PHINode>(I);
for (unsigned i = 0; i < PN->getNumIncomingValues(); ++i)
if (!ExpressionConvertableToType(PN->getIncomingValue(i), Ty, CTMap))
return false;
return true;
}
case Instruction::GetElementPtr: {
// GetElementPtr's are directly convertable to a pointer type if they have
// a number of zeros at the end. Because removing these values does not
// change the logical offset of the GEP, it is okay and fair to remove them.
// This can change this:
// %t1 = getelementptr %Hosp * %hosp, ubyte 4, ubyte 0 ; <%List **>
// %t2 = cast %List * * %t1 to %List *
// into
// %t2 = getelementptr %Hosp * %hosp, ubyte 4 ; <%List *>
//
GetElementPtrInst *GEP = cast<GetElementPtrInst>(I);
const PointerType *PTy = dyn_cast<PointerType>(Ty);
if (!PTy) return false;
// Check to see if there are zero elements that we can remove from the
// index array. If there are, check to see if removing them causes us to
// get to the right type...
//
vector<ConstPoolVal*> Indices = GEP->getIndices();
const Type *BaseType = GEP->getPtrOperand()->getType();
while (Indices.size() &&
cast<ConstPoolUInt>(Indices.back())->getValue() == 0) {
Indices.pop_back();
const Type *ElTy = GetElementPtrInst::getIndexedType(BaseType, Indices,
true);
if (ElTy == PTy->getValueType())
return true; // Found a match!!
}
break; // No match, maybe next time.
}
}
return false;
}
static Value *ConvertExpressionToType(Value *V, const Type *Ty,
ValueMapCache &VMC) {
ValueMapCache::ExprMapTy::iterator VMCI = VMC.ExprMap.find(V);
if (VMCI != VMC.ExprMap.end())
return VMCI->second;
#ifdef DEBUG_EXPR_CONVERT
cerr << "CETT: " << (void*)V << " " << V;
#endif
Instruction *I = dyn_cast<Instruction>(V);
if (I == 0)
if (ConstPoolVal *CPV = cast<ConstPoolVal>(V)) {
// Constants are converted by constant folding the cast that is required.
// We assume here that all casts are implemented for constant prop.
Value *Result = opt::ConstantFoldCastInstruction(CPV, Ty);
if (!Result) cerr << "Couldn't fold " << CPV << " to " << Ty << endl;
assert(Result && "ConstantFoldCastInstruction Failed!!!");
// Add the instruction to the expression map
VMC.ExprMap[V] = Result;
return Result;
}
BasicBlock *BB = I->getParent();
BasicBlock::InstListType &BIL = BB->getInstList();
string Name = I->getName(); if (!Name.empty()) I->setName("");
Instruction *Res; // Result of conversion
ValueHandle IHandle(I); // Prevent I from being removed!
ConstPoolVal *Dummy = ConstPoolVal::getNullConstant(Ty);
//cerr << endl << endl << "Type:\t" << Ty << "\nInst: " << I << "BB Before: " << BB << endl;
switch (I->getOpcode()) {
case Instruction::Cast:
Res = new CastInst(I->getOperand(0), Ty, Name);
break;
case Instruction::Add:
case Instruction::Sub:
Res = BinaryOperator::create(cast<BinaryOperator>(I)->getOpcode(),
Dummy, Dummy, Name);
VMC.ExprMap[I] = Res; // Add node to expression eagerly
Res->setOperand(0, ConvertExpressionToType(I->getOperand(0), Ty, VMC));
Res->setOperand(1, ConvertExpressionToType(I->getOperand(1), Ty, VMC));
break;
case Instruction::Shl:
case Instruction::Shr:
Res = new ShiftInst(cast<ShiftInst>(I)->getOpcode(), Dummy,
I->getOperand(1), Name);
VMC.ExprMap[I] = Res;
Res->setOperand(0, ConvertExpressionToType(I->getOperand(0), Ty, VMC));
break;
case Instruction::Load: {
LoadInst *LI = cast<LoadInst>(I);
assert(!LI->hasIndices());
Res = new LoadInst(ConstPoolVal::getNullConstant(PointerType::get(Ty)),
Name);
VMC.ExprMap[I] = Res;
Res->setOperand(0, ConvertExpressionToType(LI->getPtrOperand(),
PointerType::get(Ty), VMC));
break;
}
case Instruction::PHINode: {
PHINode *OldPN = cast<PHINode>(I);
PHINode *NewPN = new PHINode(Ty, Name);
VMC.ExprMap[I] = NewPN; // Add node to expression eagerly
while (OldPN->getNumOperands()) {
BasicBlock *BB = OldPN->getIncomingBlock(0);
Value *OldVal = OldPN->getIncomingValue(0);
ValueHandle OldValHandle(OldVal);
OldPN->removeIncomingValue(BB);
Value *V = ConvertExpressionToType(OldVal, Ty, VMC);
NewPN->addIncoming(V, BB);
}
Res = NewPN;
break;
}
case Instruction::GetElementPtr: {
// GetElementPtr's are directly convertable to a pointer type if they have
// a number of zeros at the end. Because removing these values does not
// change the logical offset of the GEP, it is okay and fair to remove them.
// This can change this:
// %t1 = getelementptr %Hosp * %hosp, ubyte 4, ubyte 0 ; <%List **>
// %t2 = cast %List * * %t1 to %List *
// into
// %t2 = getelementptr %Hosp * %hosp, ubyte 4 ; <%List *>
//
GetElementPtrInst *GEP = cast<GetElementPtrInst>(I);
// Check to see if there are zero elements that we can remove from the
// index array. If there are, check to see if removing them causes us to
// get to the right type...
//
vector<ConstPoolVal*> Indices = GEP->getIndices();
const Type *BaseType = GEP->getPtrOperand()->getType();
const Type *PVTy = cast<PointerType>(Ty)->getValueType();
Res = 0;
while (Indices.size() &&
cast<ConstPoolUInt>(Indices.back())->getValue() == 0) {
Indices.pop_back();
if (GetElementPtrInst::getIndexedType(BaseType, Indices, true) == PVTy) {
if (Indices.size() == 0) {
Res = new CastInst(GEP->getPtrOperand(), BaseType); // NOOP
} else {
Res = new GetElementPtrInst(GEP->getPtrOperand(), Indices, Name);
}
break;
}
}
assert(Res && "Didn't find match!");
break; // No match, maybe next time.
}
default:
assert(0 && "Expression convertable, but don't know how to convert?");
return 0;
}
BasicBlock::iterator It = find(BIL.begin(), BIL.end(), I);
assert(It != BIL.end() && "Instruction not in own basic block??");
BIL.insert(It, Res);
// Add the instruction to the expression map
VMC.ExprMap[I] = Res;
// Expressions are only convertable if all of the users of the expression can
// have this value converted. This makes use of the map to avoid infinite
// recursion.
//
unsigned NumUses = I->use_size();
for (unsigned It = 0; It < NumUses; ) {
unsigned OldSize = NumUses;
ConvertOperandToType(*(I->use_begin()+It), I, Res, VMC);
NumUses = I->use_size();
if (NumUses == OldSize) ++It;
}
#ifdef DEBUG_EXPR_CONVERT
cerr << "ExpIn: " << (void*)I << " " << I
<< "ExpOut: " << (void*)Res << " " << Res;
cerr << "ExpCREATED: " << (void*)Res << " " << Res;
#endif
if (I->use_empty()) {
#ifdef DEBUG_EXPR_CONVERT
cerr << "EXPR DELETING: " << (void*)I << " " << I;
#endif
BIL.remove(I);
delete I;
}
return Res;
}
// RetValConvertableToType - Return true if it is possible
bool RetValConvertableToType(Value *V, const Type *Ty,
ValueTypeCache &ConvertedTypes) {
ValueTypeCache::iterator I = ConvertedTypes.find(V);
if (I != ConvertedTypes.end()) return I->second == Ty;
ConvertedTypes[V] = Ty;
// It is safe to convert the specified value to the specified type IFF all of
// the uses of the value can be converted to accept the new typed value.
//
for (Value::use_iterator I = V->use_begin(), E = V->use_end(); I != E; ++I)
if (!OperandConvertableToType(*I, V, Ty, ConvertedTypes))
return false;
return true;
}
// OperandConvertableToType - Return true if it is possible to convert operand
// V of User (instruction) U to the specified type. This is true iff it is
// possible to change the specified instruction to accept this. CTMap is a map
// of converted types, so that circular definitions will see the future type of
// the expression, not the static current type.
//
static bool OperandConvertableToType(User *U, Value *V, const Type *Ty,
ValueTypeCache &CTMap) {
assert(V->getType() != Ty &&
"OperandConvertableToType: Operand is already right type!");
Instruction *I = dyn_cast<Instruction>(U);
if (I == 0) return false; // We can't convert!
switch (I->getOpcode()) {
case Instruction::Cast:
assert(I->getOperand(0) == V);
// We can convert the expr if the cast destination type is losslessly
// convertable to the requested type.
return losslessCastableTypes(Ty, I->getOperand(0)->getType());
case Instruction::Add:
case Instruction::Sub: {
Value *OtherOp = I->getOperand((V == I->getOperand(0)) ? 1 : 0);
return RetValConvertableToType(I, Ty, CTMap) &&
ExpressionConvertableToType(OtherOp, Ty, CTMap);
}
case Instruction::SetEQ:
case Instruction::SetNE: {
Value *OtherOp = I->getOperand((V == I->getOperand(0)) ? 1 : 0);
return ExpressionConvertableToType(OtherOp, Ty, CTMap);
}
case Instruction::Shr:
if (Ty->isSigned() != V->getType()->isSigned()) return false;
// FALL THROUGH
case Instruction::Shl:
assert(I->getOperand(0) == V);
return RetValConvertableToType(I, Ty, CTMap);
case Instruction::Load:
assert(I->getOperand(0) == V);
if (const PointerType *PT = dyn_cast<PointerType>(Ty)) {
LoadInst *LI = cast<LoadInst>(I);
const Type *PVTy = PT->getValueType();
if (LI->hasIndices() || isa<ArrayType>(PVTy) ||
TD.getTypeSize(PVTy) != TD.getTypeSize(LI->getType()))
return false;
return RetValConvertableToType(LI, PT->getValueType(), CTMap);
}
return false;
case Instruction::Store: {
StoreInst *SI = cast<StoreInst>(I);
if (SI->hasIndices()) return false;
if (V == I->getOperand(0)) {
// Can convert the store if we can convert the pointer operand to match
// the new value type...
return ExpressionConvertableToType(I->getOperand(1), PointerType::get(Ty),
CTMap);
} else if (const PointerType *PT = dyn_cast<PointerType>(Ty)) {
if (isa<ArrayType>(PT->getValueType()))
return false; // Avoid getDataSize on unsized array type!
assert(V == I->getOperand(1));
// Must move the same amount of data...
if (TD.getTypeSize(PT->getValueType()) !=
TD.getTypeSize(I->getOperand(0)->getType())) return false;
// Can convert store if the incoming value is convertable...
return ExpressionConvertableToType(I->getOperand(0), PT->getValueType(),
CTMap);
}
return false;
}
case Instruction::PHINode: {
PHINode *PN = cast<PHINode>(I);
for (unsigned i = 0; i < PN->getNumIncomingValues(); ++i)
if (!ExpressionConvertableToType(PN->getIncomingValue(i), Ty, CTMap))
return false;
return true;
}
#if 0
case Instruction::GetElementPtr: {
// GetElementPtr's are directly convertable to a pointer type if they have
// a number of zeros at the end. Because removing these values does not
// change the logical offset of the GEP, it is okay and fair to remove them.
// This can change this:
// %t1 = getelementptr %Hosp * %hosp, ubyte 4, ubyte 0 ; <%List **>
// %t2 = cast %List * * %t1 to %List *
// into
// %t2 = getelementptr %Hosp * %hosp, ubyte 4 ; <%List *>
//
GetElementPtrInst *GEP = cast<GetElementPtrInst>(I);
const PointerType *PTy = dyn_cast<PointerType>(Ty);
if (!PTy) return false;
// Check to see if there are zero elements that we can remove from the
// index array. If there are, check to see if removing them causes us to
// get to the right type...
//
vector<ConstPoolVal*> Indices = GEP->getIndices();
const Type *BaseType = GEP->getPtrOperand()->getType();
while (Indices.size() &&
cast<ConstPoolUInt>(Indices.back())->getValue() == 0) {
Indices.pop_back();
const Type *ElTy = GetElementPtrInst::getIndexedType(BaseType, Indices,
true);
if (ElTy == PTy->getValueType())
return true; // Found a match!!
}
break; // No match, maybe next time.
}
#endif
}
return false;
}
void ConvertUsersType(Value *V, Value *NewVal, ValueMapCache &VMC) {
ValueHandle VH(V);
unsigned NumUses = V->use_size();
for (unsigned It = 0; It < NumUses; ) {
unsigned OldSize = NumUses;
ConvertOperandToType(*(V->use_begin()+It), V, NewVal, VMC);
NumUses = V->use_size();
if (NumUses == OldSize) ++It;
}
}
static void ConvertOperandToType(User *U, Value *OldVal, Value *NewVal,
ValueMapCache &VMC) {
if (isa<ValueHandle>(U)) return; // Valuehandles don't let go of operands...
if (VMC.OperandsMapped.count(U)) return;
VMC.OperandsMapped.insert(U);
ValueMapCache::ExprMapTy::iterator VMCI = VMC.ExprMap.find(U);
if (VMCI != VMC.ExprMap.end())
return;
Instruction *I = cast<Instruction>(U); // Only Instructions convertable
BasicBlock *BB = I->getParent();
BasicBlock::InstListType &BIL = BB->getInstList();
string Name = I->getName(); if (!Name.empty()) I->setName("");
Instruction *Res; // Result of conversion
//cerr << endl << endl << "Type:\t" << Ty << "\nInst: " << I << "BB Before: " << BB << endl;
// Prevent I from being removed...
ValueHandle IHandle(I);
const Type *NewTy = NewVal->getType();
ConstPoolVal *Dummy = (NewTy != Type::VoidTy) ?
ConstPoolVal::getNullConstant(NewTy) : 0;
switch (I->getOpcode()) {
case Instruction::Cast:
assert(I->getOperand(0) == OldVal);
Res = new CastInst(NewVal, I->getType(), Name);
break;
case Instruction::Add:
case Instruction::Sub:
case Instruction::SetEQ:
case Instruction::SetNE: {
Res = BinaryOperator::create(cast<BinaryOperator>(I)->getOpcode(),
Dummy, Dummy, Name);
VMC.ExprMap[I] = Res; // Add node to expression eagerly
unsigned OtherIdx = (OldVal == I->getOperand(0)) ? 1 : 0;
Value *OtherOp = I->getOperand(OtherIdx);
Value *NewOther = ConvertExpressionToType(OtherOp, NewTy, VMC);
Res->setOperand(OtherIdx, NewOther);
Res->setOperand(!OtherIdx, NewVal);
break;
}
case Instruction::Shl:
case Instruction::Shr:
assert(I->getOperand(0) == OldVal);
Res = new ShiftInst(cast<ShiftInst>(I)->getOpcode(), NewVal,
I->getOperand(1), Name);
break;
case Instruction::Load:
assert(I->getOperand(0) == OldVal);
Res = new LoadInst(NewVal, Name);
break;
case Instruction::Store: {
if (I->getOperand(0) == OldVal) { // Replace the source value
const PointerType *NewPT = PointerType::get(NewTy);
Res = new StoreInst(NewVal, ConstPoolVal::getNullConstant(NewPT));
VMC.ExprMap[I] = Res;
Res->setOperand(1, ConvertExpressionToType(I->getOperand(1), NewPT, VMC));
} else { // Replace the source pointer
const Type *ValTy = cast<PointerType>(NewTy)->getValueType();
Res = new StoreInst(ConstPoolVal::getNullConstant(ValTy), NewVal);
VMC.ExprMap[I] = Res;
Res->setOperand(0, ConvertExpressionToType(I->getOperand(0), ValTy, VMC));
}
break;
}
case Instruction::PHINode: {
PHINode *OldPN = cast<PHINode>(I);
PHINode *NewPN = new PHINode(NewTy, Name);
VMC.ExprMap[I] = NewPN;
while (OldPN->getNumOperands()) {
BasicBlock *BB = OldPN->getIncomingBlock(0);
Value *OldVal = OldPN->getIncomingValue(0);
OldPN->removeIncomingValue(BB);
Value *V = ConvertExpressionToType(OldVal, NewTy, VMC);
NewPN->addIncoming(V, BB);
}
Res = NewPN;
break;
}
#if 0
case Instruction::GetElementPtr: {
// GetElementPtr's are directly convertable to a pointer type if they have
// a number of zeros at the end. Because removing these values does not
// change the logical offset of the GEP, it is okay and fair to remove them.
// This can change this:
// %t1 = getelementptr %Hosp * %hosp, ubyte 4, ubyte 0 ; <%List **>
// %t2 = cast %List * * %t1 to %List *
// into
// %t2 = getelementptr %Hosp * %hosp, ubyte 4 ; <%List *>
//
GetElementPtrInst *GEP = cast<GetElementPtrInst>(I);
// Check to see if there are zero elements that we can remove from the
// index array. If there are, check to see if removing them causes us to
// get to the right type...
//
vector<ConstPoolVal*> Indices = GEP->getIndices();
const Type *BaseType = GEP->getPtrOperand()->getType();
const Type *PVTy = cast<PointerType>(Ty)->getValueType();
Res = 0;
while (Indices.size() &&
cast<ConstPoolUInt>(Indices.back())->getValue() == 0) {
Indices.pop_back();
if (GetElementPtrInst::getIndexedType(BaseType, Indices, true) == PVTy) {
if (Indices.size() == 0) {
Res = new CastInst(GEP->getPtrOperand(), BaseType); // NOOP
} else {
Res = new GetElementPtrInst(GEP->getPtrOperand(), Indices, Name);
}
break;
}
}
assert(Res && "Didn't find match!");
break; // No match, maybe next time.
}
#endif
default:
assert(0 && "Expression convertable, but don't know how to convert?");
return;
}
BasicBlock::iterator It = find(BIL.begin(), BIL.end(), I);
assert(It != BIL.end() && "Instruction not in own basic block??");
BIL.insert(It, Res); // Keep It pointing to old instruction
#ifdef DEBUG_EXPR_CONVERT
cerr << "COT CREATED: " << (void*)Res << " " << Res;
cerr << "In: " << (void*)I << " " << I << "Out: " << (void*)Res << " " << Res;
#endif
// Add the instruction to the expression map
VMC.ExprMap[I] = Res;
if (I->getType() != Res->getType())
ConvertUsersType(I, Res, VMC);
else {
for (unsigned It = 0; It < I->use_size(); ) {
User *Use = *(I->use_begin()+It);
if (isa<ValueHandle>(Use)) // Don't remove ValueHandles!
++It;
else
Use->replaceUsesOfWith(I, Res);
}
if (I->use_empty()) {
// Now we just need to remove the old instruction so we don't get infinite
// loops. Note that we cannot use DCE because DCE won't remove a store
// instruction, for example.
//
#ifdef DEBUG_EXPR_CONVERT
cerr << "DELETING: " << (void*)I << " " << I;
#endif
BIL.remove(I);
delete I;
} else {
for (Value::use_iterator UI = I->use_begin(), UE = I->use_end();
UI != UE; ++UI)
assert(isa<ValueHandle>((Value*)*UI) && "Uses of Instruction remain!!!");
}
}
}
ValueHandle::ValueHandle(Value *V) : Instruction(Type::VoidTy, UserOp1, "") {
#ifdef DEBUG_EXPR_CONVERT
cerr << "VH AQUIRING: " << (void*)V << " " << V;
#endif
Operands.push_back(Use(V, this));
}
static void RecursiveDelete(Instruction *I) {
if (!I || !I->use_empty()) return;
assert(I->getParent() && "Inst not in basic block!");
#ifdef DEBUG_EXPR_CONVERT
cerr << "VH DELETING: " << (void*)I << " " << I;
#endif
for (User::op_iterator OI = I->op_begin(), OE = I->op_end();
OI != OE; ++OI) {
Instruction *U = dyn_cast<Instruction>(*OI);
if (U) {
*OI = 0;
RecursiveDelete(dyn_cast<Instruction>(U));
}
}
I->getParent()->getInstList().remove(I);
delete I;
}
ValueHandle::~ValueHandle() {
if (Operands[0]->use_size() == 1) {
Value *V = Operands[0];
Operands[0] = 0; // Drop use!
// Now we just need to remove the old instruction so we don't get infinite
// loops. Note that we cannot use DCE because DCE won't remove a store
// instruction, for example.
//
RecursiveDelete(cast<Instruction>(V));
} else {
#ifdef DEBUG_EXPR_CONVERT
cerr << "VH RELEASING: " << (void*)Operands[0].get() << " " << Operands[0]->use_size() << " " << Operands[0];
#endif
}
}
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