forked from OSchip/llvm-project
rename InstValue to LatticeValue, as it holds for more than instructions.
llvm-svn: 17818
This commit is contained in:
Chris Lattner
parent
dacbf466c8
commit
4f0316229c
|
|
@ -21,6 +21,7 @@
|
|||
//
|
||||
//===----------------------------------------------------------------------===//
|
||||
|
||||
#define DEBUG_TYPE "sccp"
|
||||
#include "llvm/Transforms/Scalar.h"
|
||||
#include "llvm/Constants.h"
|
||||
#include "llvm/Function.h"
|
||||
|
|
@ -38,13 +39,13 @@
|
|||
#include <set>
|
||||
using namespace llvm;
|
||||
|
||||
// InstVal class - This class represents the different lattice values that an
|
||||
// LatticeVal class - This class represents the different lattice values that an
|
||||
// instruction may occupy. It is a simple class with value semantics.
|
||||
//
|
||||
namespace {
|
||||
Statistic<> NumInstRemoved("sccp", "Number of instructions removed");
|
||||
|
||||
class InstVal {
|
||||
class LatticeVal {
|
||||
enum {
|
||||
undefined, // This instruction has no known value
|
||||
constant, // This instruction has a constant value
|
||||
|
|
@ -52,7 +53,7 @@ class InstVal {
|
|||
} LatticeValue; // The current lattice position
|
||||
Constant *ConstantVal; // If Constant value, the current value
|
||||
public:
|
||||
inline InstVal() : LatticeValue(undefined), ConstantVal(0) {}
|
||||
inline LatticeVal() : LatticeValue(undefined), ConstantVal(0) {}
|
||||
|
||||
// markOverdefined - Return true if this is a new status to be in...
|
||||
inline bool markOverdefined() {
|
||||
|
|
@ -95,7 +96,7 @@ public:
|
|||
///
|
||||
class SCCPSolver : public InstVisitor<SCCPSolver> {
|
||||
std::set<BasicBlock*> BBExecutable;// The basic blocks that are executable
|
||||
hash_map<Value*, InstVal> ValueState; // The state each value is in...
|
||||
hash_map<Value*, LatticeVal> ValueState; // The state each value is in...
|
||||
|
||||
// The reason for two worklists is that overdefined is the lowest state
|
||||
// on the lattice, and moving things to overdefined as fast as possible
|
||||
|
|
@ -139,8 +140,8 @@ public:
|
|||
}
|
||||
|
||||
/// getValueMapping - Once we have solved for constants, return the mapping of
|
||||
/// LLVM values to InstVals.
|
||||
hash_map<Value*, InstVal> &getValueMapping() {
|
||||
/// LLVM values to LatticeVals.
|
||||
hash_map<Value*, LatticeVal> &getValueMapping() {
|
||||
return ValueState;
|
||||
}
|
||||
|
||||
|
|
@ -149,7 +150,7 @@ private:
|
|||
// is not already a constant, add it to the instruction work list so that
|
||||
// the users of the instruction are updated later.
|
||||
//
|
||||
inline void markConstant(InstVal &IV, Instruction *I, Constant *C) {
|
||||
inline void markConstant(LatticeVal &IV, Instruction *I, Constant *C) {
|
||||
if (IV.markConstant(C)) {
|
||||
DEBUG(std::cerr << "markConstant: " << *C << ": " << *I);
|
||||
InstWorkList.push_back(I);
|
||||
|
|
@ -163,7 +164,7 @@ private:
|
|||
// value is not already overdefined, add it to the overdefined instruction
|
||||
// work list so that the users of the instruction are updated later.
|
||||
|
||||
inline void markOverdefined(InstVal &IV, Instruction *I) {
|
||||
inline void markOverdefined(LatticeVal &IV, Instruction *I) {
|
||||
if (IV.markOverdefined()) {
|
||||
DEBUG(std::cerr << "markOverdefined: " << *I);
|
||||
// Only instructions go on the work list
|
||||
|
|
@ -174,14 +175,14 @@ private:
|
|||
markOverdefined(ValueState[I], I);
|
||||
}
|
||||
|
||||
// getValueState - Return the InstVal object that corresponds to the value.
|
||||
// getValueState - Return the LatticeVal object that corresponds to the value.
|
||||
// This function is necessary because not all values should start out in the
|
||||
// underdefined state... Argument's should be overdefined, and
|
||||
// constants should be marked as constants. If a value is not known to be an
|
||||
// Instruction object, then use this accessor to get its value from the map.
|
||||
//
|
||||
inline InstVal &getValueState(Value *V) {
|
||||
hash_map<Value*, InstVal>::iterator I = ValueState.find(V);
|
||||
inline LatticeVal &getValueState(Value *V) {
|
||||
hash_map<Value*, LatticeVal>::iterator I = ValueState.find(V);
|
||||
if (I != ValueState.end()) return I->second; // Common case, in the map
|
||||
|
||||
if (isa<UndefValue>(V)) {
|
||||
|
|
@ -291,7 +292,7 @@ void SCCPSolver::getFeasibleSuccessors(TerminatorInst &TI,
|
|||
if (BI->isUnconditional()) {
|
||||
Succs[0] = true;
|
||||
} else {
|
||||
InstVal &BCValue = getValueState(BI->getCondition());
|
||||
LatticeVal &BCValue = getValueState(BI->getCondition());
|
||||
if (BCValue.isOverdefined() ||
|
||||
(BCValue.isConstant() && !isa<ConstantBool>(BCValue.getConstant()))) {
|
||||
// Overdefined condition variables, and branches on unfoldable constant
|
||||
|
|
@ -306,7 +307,7 @@ void SCCPSolver::getFeasibleSuccessors(TerminatorInst &TI,
|
|||
// Invoke instructions successors are always executable.
|
||||
Succs[0] = Succs[1] = true;
|
||||
} else if (SwitchInst *SI = dyn_cast<SwitchInst>(&TI)) {
|
||||
InstVal &SCValue = getValueState(SI->getCondition());
|
||||
LatticeVal &SCValue = getValueState(SI->getCondition());
|
||||
if (SCValue.isOverdefined() || // Overdefined condition?
|
||||
(SCValue.isConstant() && !isa<ConstantInt>(SCValue.getConstant()))) {
|
||||
// All destinations are executable!
|
||||
|
|
@ -347,7 +348,7 @@ bool SCCPSolver::isEdgeFeasible(BasicBlock *From, BasicBlock *To) {
|
|||
if (BI->isUnconditional())
|
||||
return true;
|
||||
else {
|
||||
InstVal &BCValue = getValueState(BI->getCondition());
|
||||
LatticeVal &BCValue = getValueState(BI->getCondition());
|
||||
if (BCValue.isOverdefined()) {
|
||||
// Overdefined condition variables mean the branch could go either way.
|
||||
return true;
|
||||
|
|
@ -365,7 +366,7 @@ bool SCCPSolver::isEdgeFeasible(BasicBlock *From, BasicBlock *To) {
|
|||
// Invoke instructions successors are always executable.
|
||||
return true;
|
||||
} else if (SwitchInst *SI = dyn_cast<SwitchInst>(TI)) {
|
||||
InstVal &SCValue = getValueState(SI->getCondition());
|
||||
LatticeVal &SCValue = getValueState(SI->getCondition());
|
||||
if (SCValue.isOverdefined()) { // Overdefined condition?
|
||||
// All destinations are executable!
|
||||
return true;
|
||||
|
|
@ -409,7 +410,7 @@ bool SCCPSolver::isEdgeFeasible(BasicBlock *From, BasicBlock *To) {
|
|||
// successors executable.
|
||||
//
|
||||
void SCCPSolver::visitPHINode(PHINode &PN) {
|
||||
InstVal &PNIV = getValueState(&PN);
|
||||
LatticeVal &PNIV = getValueState(&PN);
|
||||
if (PNIV.isOverdefined()) {
|
||||
// There may be instructions using this PHI node that are not overdefined
|
||||
// themselves. If so, make sure that they know that the PHI node operand
|
||||
|
|
@ -443,7 +444,7 @@ void SCCPSolver::visitPHINode(PHINode &PN) {
|
|||
//
|
||||
Constant *OperandVal = 0;
|
||||
for (unsigned i = 0, e = PN.getNumIncomingValues(); i != e; ++i) {
|
||||
InstVal &IV = getValueState(PN.getIncomingValue(i));
|
||||
LatticeVal &IV = getValueState(PN.getIncomingValue(i));
|
||||
if (IV.isUndefined()) continue; // Doesn't influence PHI node.
|
||||
|
||||
if (isEdgeFeasible(PN.getIncomingBlock(i), PN.getParent())) {
|
||||
|
|
@ -494,7 +495,7 @@ void SCCPSolver::visitTerminatorInst(TerminatorInst &TI) {
|
|||
|
||||
void SCCPSolver::visitCastInst(CastInst &I) {
|
||||
Value *V = I.getOperand(0);
|
||||
InstVal &VState = getValueState(V);
|
||||
LatticeVal &VState = getValueState(V);
|
||||
if (VState.isOverdefined()) // Inherit overdefinedness of operand
|
||||
markOverdefined(&I);
|
||||
else if (VState.isConstant()) // Propagate constant value
|
||||
|
|
@ -502,18 +503,18 @@ void SCCPSolver::visitCastInst(CastInst &I) {
|
|||
}
|
||||
|
||||
void SCCPSolver::visitSelectInst(SelectInst &I) {
|
||||
InstVal &CondValue = getValueState(I.getCondition());
|
||||
LatticeVal &CondValue = getValueState(I.getCondition());
|
||||
if (CondValue.isOverdefined())
|
||||
markOverdefined(&I);
|
||||
else if (CondValue.isConstant()) {
|
||||
if (CondValue.getConstant() == ConstantBool::True) {
|
||||
InstVal &Val = getValueState(I.getTrueValue());
|
||||
LatticeVal &Val = getValueState(I.getTrueValue());
|
||||
if (Val.isOverdefined())
|
||||
markOverdefined(&I);
|
||||
else if (Val.isConstant())
|
||||
markConstant(&I, Val.getConstant());
|
||||
} else if (CondValue.getConstant() == ConstantBool::False) {
|
||||
InstVal &Val = getValueState(I.getFalseValue());
|
||||
LatticeVal &Val = getValueState(I.getFalseValue());
|
||||
if (Val.isOverdefined())
|
||||
markOverdefined(&I);
|
||||
else if (Val.isConstant())
|
||||
|
|
@ -525,11 +526,11 @@ void SCCPSolver::visitSelectInst(SelectInst &I) {
|
|||
|
||||
// Handle BinaryOperators and Shift Instructions...
|
||||
void SCCPSolver::visitBinaryOperator(Instruction &I) {
|
||||
InstVal &IV = ValueState[&I];
|
||||
LatticeVal &IV = ValueState[&I];
|
||||
if (IV.isOverdefined()) return;
|
||||
|
||||
InstVal &V1State = getValueState(I.getOperand(0));
|
||||
InstVal &V2State = getValueState(I.getOperand(1));
|
||||
LatticeVal &V1State = getValueState(I.getOperand(0));
|
||||
LatticeVal &V2State = getValueState(I.getOperand(1));
|
||||
|
||||
if (V1State.isOverdefined() || V2State.isOverdefined()) {
|
||||
// If both operands are PHI nodes, it is possible that this instruction has
|
||||
|
|
@ -544,11 +545,12 @@ void SCCPSolver::visitBinaryOperator(Instruction &I) {
|
|||
// evaluating this expression with all incoming value pairs is the
|
||||
// same, then this expression is a constant even though the PHI node
|
||||
// is not a constant!
|
||||
InstVal Result;
|
||||
LatticeVal Result;
|
||||
for (unsigned i = 0, e = PN1->getNumIncomingValues(); i != e; ++i) {
|
||||
InstVal &In1 = getValueState(PN1->getIncomingValue(i));
|
||||
LatticeVal &In1 = getValueState(PN1->getIncomingValue(i));
|
||||
BasicBlock *InBlock = PN1->getIncomingBlock(i);
|
||||
InstVal &In2 =getValueState(PN2->getIncomingValueForBlock(InBlock));
|
||||
LatticeVal &In2 =
|
||||
getValueState(PN2->getIncomingValueForBlock(InBlock));
|
||||
|
||||
if (In1.isOverdefined() || In2.isOverdefined()) {
|
||||
Result.markOverdefined();
|
||||
|
|
@ -611,14 +613,14 @@ void SCCPSolver::visitBinaryOperator(Instruction &I) {
|
|||
// can turn this into a getelementptr ConstantExpr.
|
||||
//
|
||||
void SCCPSolver::visitGetElementPtrInst(GetElementPtrInst &I) {
|
||||
InstVal &IV = ValueState[&I];
|
||||
LatticeVal &IV = ValueState[&I];
|
||||
if (IV.isOverdefined()) return;
|
||||
|
||||
std::vector<Constant*> Operands;
|
||||
Operands.reserve(I.getNumOperands());
|
||||
|
||||
for (unsigned i = 0, e = I.getNumOperands(); i != e; ++i) {
|
||||
InstVal &State = getValueState(I.getOperand(i));
|
||||
LatticeVal &State = getValueState(I.getOperand(i));
|
||||
if (State.isUndefined())
|
||||
return; // Operands are not resolved yet...
|
||||
else if (State.isOverdefined()) {
|
||||
|
|
@ -664,10 +666,10 @@ static Constant *GetGEPGlobalInitializer(Constant *C, ConstantExpr *CE) {
|
|||
// Handle load instructions. If the operand is a constant pointer to a constant
|
||||
// global, we can replace the load with the loaded constant value!
|
||||
void SCCPSolver::visitLoadInst(LoadInst &I) {
|
||||
InstVal &IV = ValueState[&I];
|
||||
LatticeVal &IV = ValueState[&I];
|
||||
if (IV.isOverdefined()) return;
|
||||
|
||||
InstVal &PtrVal = getValueState(I.getOperand(0));
|
||||
LatticeVal &PtrVal = getValueState(I.getOperand(0));
|
||||
if (PtrVal.isUndefined()) return; // The pointer is not resolved yet!
|
||||
if (PtrVal.isConstant() && !I.isVolatile()) {
|
||||
Value *Ptr = PtrVal.getConstant();
|
||||
|
|
@ -702,7 +704,7 @@ void SCCPSolver::visitLoadInst(LoadInst &I) {
|
|||
}
|
||||
|
||||
void SCCPSolver::visitCallInst(CallInst &I) {
|
||||
InstVal &IV = ValueState[&I];
|
||||
LatticeVal &IV = ValueState[&I];
|
||||
if (IV.isOverdefined()) return;
|
||||
|
||||
Function *F = I.getCalledFunction();
|
||||
|
|
@ -715,7 +717,7 @@ void SCCPSolver::visitCallInst(CallInst &I) {
|
|||
Operands.reserve(I.getNumOperands()-1);
|
||||
|
||||
for (unsigned i = 1, e = I.getNumOperands(); i != e; ++i) {
|
||||
InstVal &State = getValueState(I.getOperand(i));
|
||||
LatticeVal &State = getValueState(I.getOperand(i));
|
||||
if (State.isUndefined())
|
||||
return; // Operands are not resolved yet...
|
||||
else if (State.isOverdefined()) {
|
||||
|
|
@ -845,12 +847,12 @@ bool SCCP::runOnFunction(Function &F) {
|
|||
// constants if we have found them to be of constant values.
|
||||
//
|
||||
bool MadeChanges = false;
|
||||
hash_map<Value*, InstVal> &Values = Solver.getValueMapping();
|
||||
hash_map<Value*, LatticeVal> &Values = Solver.getValueMapping();
|
||||
for (Function::iterator BB = F.begin(), BBE = F.end(); BB != BBE; ++BB)
|
||||
for (BasicBlock::iterator BI = BB->begin(), E = BB->end(); BI != E; ) {
|
||||
Instruction *Inst = BI++;
|
||||
if (Inst->getType() != Type::VoidTy) {
|
||||
InstVal &IV = Values[Inst];
|
||||
LatticeVal &IV = Values[Inst];
|
||||
if (IV.isConstant() || IV.isUndefined()) {
|
||||
Constant *Const;
|
||||
if (IV.isConstant()) {
|
||||
|
|
|
|||
Loading…
Reference in New Issue