[llvm-commits] [llvm] r40469 - in /llvm/trunk: include/llvm/LinkAllPasses.h include/llvm/Transforms/Scalar.h lib/Transforms/Scalar/GVN.cpp test/Transforms/GVN/ test/Transforms/GVN/basic.ll test/Transforms/GVN/dg.exp test/Transforms/GVN/mixed.ll
Owen Anderson
resistor at mac.com
Tue Jul 24 10:55:58 PDT 2007
Author: resistor
Date: Tue Jul 24 12:55:58 2007
New Revision: 40469
URL: http://llvm.org/viewvc/llvm-project?rev=40469&view=rev
Log:
Add a GVN pass, using the value numbering code I developed for GVNPRE and the
load elimination code from RedundantLoadElimination.
Added:
llvm/trunk/lib/Transforms/Scalar/GVN.cpp
llvm/trunk/test/Transforms/GVN/
llvm/trunk/test/Transforms/GVN/basic.ll
llvm/trunk/test/Transforms/GVN/dg.exp
llvm/trunk/test/Transforms/GVN/mixed.ll
Modified:
llvm/trunk/include/llvm/LinkAllPasses.h
llvm/trunk/include/llvm/Transforms/Scalar.h
Modified: llvm/trunk/include/llvm/LinkAllPasses.h
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/include/llvm/LinkAllPasses.h?rev=40469&r1=40468&r2=40469&view=diff
==============================================================================
--- llvm/trunk/include/llvm/LinkAllPasses.h (original)
+++ llvm/trunk/include/llvm/LinkAllPasses.h Tue Jul 24 12:55:58 2007
@@ -114,6 +114,7 @@
(void) llvm::createInstCountPass();
(void) llvm::createPredicateSimplifierPass();
(void) llvm::createCodeGenPreparePass();
+ (void) llvm::createGVNPass();
(void)new llvm::IntervalPartition();
(void)new llvm::FindUsedTypes();
Modified: llvm/trunk/include/llvm/Transforms/Scalar.h
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/include/llvm/Transforms/Scalar.h?rev=40469&r1=40468&r2=40469&view=diff
==============================================================================
--- llvm/trunk/include/llvm/Transforms/Scalar.h (original)
+++ llvm/trunk/include/llvm/Transforms/Scalar.h Tue Jul 24 12:55:58 2007
@@ -339,6 +339,13 @@
//===----------------------------------------------------------------------===//
//
+// GVN - This pass performs global value numbering and redundant load
+// elimination cotemporaneously.
+//
+FunctionPass *createGVNPass();
+
+//===----------------------------------------------------------------------===//
+//
// CodeGenPrepare - This pass prepares a function for instruction selection.
//
FunctionPass *createCodeGenPreparePass(const TargetLowering *TLI = 0);
Added: llvm/trunk/lib/Transforms/Scalar/GVN.cpp
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/Transforms/Scalar/GVN.cpp?rev=40469&view=auto
==============================================================================
--- llvm/trunk/lib/Transforms/Scalar/GVN.cpp (added)
+++ llvm/trunk/lib/Transforms/Scalar/GVN.cpp Tue Jul 24 12:55:58 2007
@@ -0,0 +1,816 @@
+//===- GVN.cpp - Eliminate redundant values and loads ------------===//
+//
+// The LLVM Compiler Infrastructure
+//
+// This file was developed by the Owen Anderson and is distributed under
+// the University of Illinois Open Source License. See LICENSE.TXT for details.
+//
+//===----------------------------------------------------------------------===//
+//
+// This pass performs global value numbering to eliminate fully redundant
+// instructions. It also performs simple dead load elimination.
+//
+//===----------------------------------------------------------------------===//
+
+#define DEBUG_TYPE "gvn"
+#include "llvm/Value.h"
+#include "llvm/Transforms/Scalar.h"
+#include "llvm/Instructions.h"
+#include "llvm/Function.h"
+#include "llvm/DerivedTypes.h"
+#include "llvm/Analysis/Dominators.h"
+#include "llvm/ADT/BitVector.h"
+#include "llvm/ADT/DenseMap.h"
+#include "llvm/ADT/DepthFirstIterator.h"
+#include "llvm/ADT/SmallPtrSet.h"
+#include "llvm/ADT/SmallVector.h"
+#include "llvm/ADT/Statistic.h"
+#include "llvm/Analysis/MemoryDependenceAnalysis.h"
+#include "llvm/Support/CFG.h"
+#include "llvm/Support/Compiler.h"
+using namespace llvm;
+
+//===----------------------------------------------------------------------===//
+// ValueTable Class
+//===----------------------------------------------------------------------===//
+
+/// This class holds the mapping between values and value numbers. It is used
+/// as an efficient mechanism to determine the expression-wise equivalence of
+/// two values.
+namespace {
+ struct VISIBILITY_HIDDEN Expression {
+ enum ExpressionOpcode { ADD, SUB, MUL, UDIV, SDIV, FDIV, UREM, SREM,
+ FREM, SHL, LSHR, ASHR, AND, OR, XOR, ICMPEQ,
+ ICMPNE, ICMPUGT, ICMPUGE, ICMPULT, ICMPULE,
+ ICMPSGT, ICMPSGE, ICMPSLT, ICMPSLE, FCMPOEQ,
+ FCMPOGT, FCMPOGE, FCMPOLT, FCMPOLE, FCMPONE,
+ FCMPORD, FCMPUNO, FCMPUEQ, FCMPUGT, FCMPUGE,
+ FCMPULT, FCMPULE, FCMPUNE, EXTRACT, INSERT,
+ SHUFFLE, SELECT, TRUNC, ZEXT, SEXT, FPTOUI,
+ FPTOSI, UITOFP, SITOFP, FPTRUNC, FPEXT,
+ PTRTOINT, INTTOPTR, BITCAST, GEP, EMPTY,
+ TOMBSTONE };
+
+ ExpressionOpcode opcode;
+ const Type* type;
+ uint32_t firstVN;
+ uint32_t secondVN;
+ uint32_t thirdVN;
+ SmallVector<uint32_t, 4> varargs;
+
+ Expression() { }
+ Expression(ExpressionOpcode o) : opcode(o) { }
+
+ bool operator==(const Expression &other) const {
+ if (opcode != other.opcode)
+ return false;
+ else if (opcode == EMPTY || opcode == TOMBSTONE)
+ return true;
+ else if (type != other.type)
+ return false;
+ else if (firstVN != other.firstVN)
+ return false;
+ else if (secondVN != other.secondVN)
+ return false;
+ else if (thirdVN != other.thirdVN)
+ return false;
+ else {
+ if (varargs.size() != other.varargs.size())
+ return false;
+
+ for (size_t i = 0; i < varargs.size(); ++i)
+ if (varargs[i] != other.varargs[i])
+ return false;
+
+ return true;
+ }
+ }
+
+ bool operator!=(const Expression &other) const {
+ if (opcode != other.opcode)
+ return true;
+ else if (opcode == EMPTY || opcode == TOMBSTONE)
+ return false;
+ else if (type != other.type)
+ return true;
+ else if (firstVN != other.firstVN)
+ return true;
+ else if (secondVN != other.secondVN)
+ return true;
+ else if (thirdVN != other.thirdVN)
+ return true;
+ else {
+ if (varargs.size() != other.varargs.size())
+ return true;
+
+ for (size_t i = 0; i < varargs.size(); ++i)
+ if (varargs[i] != other.varargs[i])
+ return true;
+
+ return false;
+ }
+ }
+ };
+
+ class VISIBILITY_HIDDEN ValueTable {
+ private:
+ DenseMap<Value*, uint32_t> valueNumbering;
+ DenseMap<Expression, uint32_t> expressionNumbering;
+
+ uint32_t nextValueNumber;
+
+ Expression::ExpressionOpcode getOpcode(BinaryOperator* BO);
+ Expression::ExpressionOpcode getOpcode(CmpInst* C);
+ Expression::ExpressionOpcode getOpcode(CastInst* C);
+ Expression create_expression(BinaryOperator* BO);
+ Expression create_expression(CmpInst* C);
+ Expression create_expression(ShuffleVectorInst* V);
+ Expression create_expression(ExtractElementInst* C);
+ Expression create_expression(InsertElementInst* V);
+ Expression create_expression(SelectInst* V);
+ Expression create_expression(CastInst* C);
+ Expression create_expression(GetElementPtrInst* G);
+ public:
+ ValueTable() { nextValueNumber = 1; }
+ uint32_t lookup_or_add(Value* V);
+ uint32_t lookup(Value* V) const;
+ void add(Value* V, uint32_t num);
+ void clear();
+ void erase(Value* v);
+ unsigned size();
+ };
+}
+
+namespace llvm {
+template <> struct DenseMapKeyInfo<Expression> {
+ static inline Expression getEmptyKey() { return Expression(Expression::EMPTY); }
+ static inline Expression getTombstoneKey() { return Expression(Expression::TOMBSTONE); }
+
+ static unsigned getHashValue(const Expression e) {
+ unsigned hash = e.opcode;
+
+ hash = e.firstVN + hash * 37;
+ hash = e.secondVN + hash * 37;
+ hash = e.thirdVN + hash * 37;
+
+ hash = (unsigned)((uintptr_t)e.type >> 4) ^
+ (unsigned)((uintptr_t)e.type >> 9) +
+ hash * 37;
+
+ for (SmallVector<uint32_t, 4>::const_iterator I = e.varargs.begin(), E = e.varargs.end();
+ I != E; ++I)
+ hash = *I + hash * 37;
+
+ return hash;
+ }
+ static bool isPod() { return true; }
+};
+}
+
+//===----------------------------------------------------------------------===//
+// ValueTable Internal Functions
+//===----------------------------------------------------------------------===//
+Expression::ExpressionOpcode
+ ValueTable::getOpcode(BinaryOperator* BO) {
+ switch(BO->getOpcode()) {
+ case Instruction::Add:
+ return Expression::ADD;
+ case Instruction::Sub:
+ return Expression::SUB;
+ case Instruction::Mul:
+ return Expression::MUL;
+ case Instruction::UDiv:
+ return Expression::UDIV;
+ case Instruction::SDiv:
+ return Expression::SDIV;
+ case Instruction::FDiv:
+ return Expression::FDIV;
+ case Instruction::URem:
+ return Expression::UREM;
+ case Instruction::SRem:
+ return Expression::SREM;
+ case Instruction::FRem:
+ return Expression::FREM;
+ case Instruction::Shl:
+ return Expression::SHL;
+ case Instruction::LShr:
+ return Expression::LSHR;
+ case Instruction::AShr:
+ return Expression::ASHR;
+ case Instruction::And:
+ return Expression::AND;
+ case Instruction::Or:
+ return Expression::OR;
+ case Instruction::Xor:
+ return Expression::XOR;
+
+ // THIS SHOULD NEVER HAPPEN
+ default:
+ assert(0 && "Binary operator with unknown opcode?");
+ return Expression::ADD;
+ }
+}
+
+Expression::ExpressionOpcode ValueTable::getOpcode(CmpInst* C) {
+ if (C->getOpcode() == Instruction::ICmp) {
+ switch (C->getPredicate()) {
+ case ICmpInst::ICMP_EQ:
+ return Expression::ICMPEQ;
+ case ICmpInst::ICMP_NE:
+ return Expression::ICMPNE;
+ case ICmpInst::ICMP_UGT:
+ return Expression::ICMPUGT;
+ case ICmpInst::ICMP_UGE:
+ return Expression::ICMPUGE;
+ case ICmpInst::ICMP_ULT:
+ return Expression::ICMPULT;
+ case ICmpInst::ICMP_ULE:
+ return Expression::ICMPULE;
+ case ICmpInst::ICMP_SGT:
+ return Expression::ICMPSGT;
+ case ICmpInst::ICMP_SGE:
+ return Expression::ICMPSGE;
+ case ICmpInst::ICMP_SLT:
+ return Expression::ICMPSLT;
+ case ICmpInst::ICMP_SLE:
+ return Expression::ICMPSLE;
+
+ // THIS SHOULD NEVER HAPPEN
+ default:
+ assert(0 && "Comparison with unknown predicate?");
+ return Expression::ICMPEQ;
+ }
+ } else {
+ switch (C->getPredicate()) {
+ case FCmpInst::FCMP_OEQ:
+ return Expression::FCMPOEQ;
+ case FCmpInst::FCMP_OGT:
+ return Expression::FCMPOGT;
+ case FCmpInst::FCMP_OGE:
+ return Expression::FCMPOGE;
+ case FCmpInst::FCMP_OLT:
+ return Expression::FCMPOLT;
+ case FCmpInst::FCMP_OLE:
+ return Expression::FCMPOLE;
+ case FCmpInst::FCMP_ONE:
+ return Expression::FCMPONE;
+ case FCmpInst::FCMP_ORD:
+ return Expression::FCMPORD;
+ case FCmpInst::FCMP_UNO:
+ return Expression::FCMPUNO;
+ case FCmpInst::FCMP_UEQ:
+ return Expression::FCMPUEQ;
+ case FCmpInst::FCMP_UGT:
+ return Expression::FCMPUGT;
+ case FCmpInst::FCMP_UGE:
+ return Expression::FCMPUGE;
+ case FCmpInst::FCMP_ULT:
+ return Expression::FCMPULT;
+ case FCmpInst::FCMP_ULE:
+ return Expression::FCMPULE;
+ case FCmpInst::FCMP_UNE:
+ return Expression::FCMPUNE;
+
+ // THIS SHOULD NEVER HAPPEN
+ default:
+ assert(0 && "Comparison with unknown predicate?");
+ return Expression::FCMPOEQ;
+ }
+ }
+}
+
+Expression::ExpressionOpcode
+ ValueTable::getOpcode(CastInst* C) {
+ switch(C->getOpcode()) {
+ case Instruction::Trunc:
+ return Expression::TRUNC;
+ case Instruction::ZExt:
+ return Expression::ZEXT;
+ case Instruction::SExt:
+ return Expression::SEXT;
+ case Instruction::FPToUI:
+ return Expression::FPTOUI;
+ case Instruction::FPToSI:
+ return Expression::FPTOSI;
+ case Instruction::UIToFP:
+ return Expression::UITOFP;
+ case Instruction::SIToFP:
+ return Expression::SITOFP;
+ case Instruction::FPTrunc:
+ return Expression::FPTRUNC;
+ case Instruction::FPExt:
+ return Expression::FPEXT;
+ case Instruction::PtrToInt:
+ return Expression::PTRTOINT;
+ case Instruction::IntToPtr:
+ return Expression::INTTOPTR;
+ case Instruction::BitCast:
+ return Expression::BITCAST;
+
+ // THIS SHOULD NEVER HAPPEN
+ default:
+ assert(0 && "Cast operator with unknown opcode?");
+ return Expression::BITCAST;
+ }
+}
+
+Expression ValueTable::create_expression(BinaryOperator* BO) {
+ Expression e;
+
+ e.firstVN = lookup_or_add(BO->getOperand(0));
+ e.secondVN = lookup_or_add(BO->getOperand(1));
+ e.thirdVN = 0;
+ e.type = BO->getType();
+ e.opcode = getOpcode(BO);
+
+ return e;
+}
+
+Expression ValueTable::create_expression(CmpInst* C) {
+ Expression e;
+
+ e.firstVN = lookup_or_add(C->getOperand(0));
+ e.secondVN = lookup_or_add(C->getOperand(1));
+ e.thirdVN = 0;
+ e.type = C->getType();
+ e.opcode = getOpcode(C);
+
+ return e;
+}
+
+Expression ValueTable::create_expression(CastInst* C) {
+ Expression e;
+
+ e.firstVN = lookup_or_add(C->getOperand(0));
+ e.secondVN = 0;
+ e.thirdVN = 0;
+ e.type = C->getType();
+ e.opcode = getOpcode(C);
+
+ return e;
+}
+
+Expression ValueTable::create_expression(ShuffleVectorInst* S) {
+ Expression e;
+
+ e.firstVN = lookup_or_add(S->getOperand(0));
+ e.secondVN = lookup_or_add(S->getOperand(1));
+ e.thirdVN = lookup_or_add(S->getOperand(2));
+ e.type = S->getType();
+ e.opcode = Expression::SHUFFLE;
+
+ return e;
+}
+
+Expression ValueTable::create_expression(ExtractElementInst* E) {
+ Expression e;
+
+ e.firstVN = lookup_or_add(E->getOperand(0));
+ e.secondVN = lookup_or_add(E->getOperand(1));
+ e.thirdVN = 0;
+ e.type = E->getType();
+ e.opcode = Expression::EXTRACT;
+
+ return e;
+}
+
+Expression ValueTable::create_expression(InsertElementInst* I) {
+ Expression e;
+
+ e.firstVN = lookup_or_add(I->getOperand(0));
+ e.secondVN = lookup_or_add(I->getOperand(1));
+ e.thirdVN = lookup_or_add(I->getOperand(2));
+ e.type = I->getType();
+ e.opcode = Expression::INSERT;
+
+ return e;
+}
+
+Expression ValueTable::create_expression(SelectInst* I) {
+ Expression e;
+
+ e.firstVN = lookup_or_add(I->getCondition());
+ e.secondVN = lookup_or_add(I->getTrueValue());
+ e.thirdVN = lookup_or_add(I->getFalseValue());
+ e.type = I->getType();
+ e.opcode = Expression::SELECT;
+
+ return e;
+}
+
+Expression ValueTable::create_expression(GetElementPtrInst* G) {
+ Expression e;
+
+ e.firstVN = lookup_or_add(G->getPointerOperand());
+ e.secondVN = 0;
+ e.thirdVN = 0;
+ e.type = G->getType();
+ e.opcode = Expression::GEP;
+
+ for (GetElementPtrInst::op_iterator I = G->idx_begin(), E = G->idx_end();
+ I != E; ++I)
+ e.varargs.push_back(lookup_or_add(*I));
+
+ return e;
+}
+
+//===----------------------------------------------------------------------===//
+// ValueTable External Functions
+//===----------------------------------------------------------------------===//
+
+/// lookup_or_add - Returns the value number for the specified value, assigning
+/// it a new number if it did not have one before.
+uint32_t ValueTable::lookup_or_add(Value* V) {
+ DenseMap<Value*, uint32_t>::iterator VI = valueNumbering.find(V);
+ if (VI != valueNumbering.end())
+ return VI->second;
+
+
+ if (BinaryOperator* BO = dyn_cast<BinaryOperator>(V)) {
+ Expression e = create_expression(BO);
+
+ DenseMap<Expression, uint32_t>::iterator EI = expressionNumbering.find(e);
+ if (EI != expressionNumbering.end()) {
+ valueNumbering.insert(std::make_pair(V, EI->second));
+ return EI->second;
+ } else {
+ expressionNumbering.insert(std::make_pair(e, nextValueNumber));
+ valueNumbering.insert(std::make_pair(V, nextValueNumber));
+
+ return nextValueNumber++;
+ }
+ } else if (CmpInst* C = dyn_cast<CmpInst>(V)) {
+ Expression e = create_expression(C);
+
+ DenseMap<Expression, uint32_t>::iterator EI = expressionNumbering.find(e);
+ if (EI != expressionNumbering.end()) {
+ valueNumbering.insert(std::make_pair(V, EI->second));
+ return EI->second;
+ } else {
+ expressionNumbering.insert(std::make_pair(e, nextValueNumber));
+ valueNumbering.insert(std::make_pair(V, nextValueNumber));
+
+ return nextValueNumber++;
+ }
+ } else if (ShuffleVectorInst* U = dyn_cast<ShuffleVectorInst>(V)) {
+ Expression e = create_expression(U);
+
+ DenseMap<Expression, uint32_t>::iterator EI = expressionNumbering.find(e);
+ if (EI != expressionNumbering.end()) {
+ valueNumbering.insert(std::make_pair(V, EI->second));
+ return EI->second;
+ } else {
+ expressionNumbering.insert(std::make_pair(e, nextValueNumber));
+ valueNumbering.insert(std::make_pair(V, nextValueNumber));
+
+ return nextValueNumber++;
+ }
+ } else if (ExtractElementInst* U = dyn_cast<ExtractElementInst>(V)) {
+ Expression e = create_expression(U);
+
+ DenseMap<Expression, uint32_t>::iterator EI = expressionNumbering.find(e);
+ if (EI != expressionNumbering.end()) {
+ valueNumbering.insert(std::make_pair(V, EI->second));
+ return EI->second;
+ } else {
+ expressionNumbering.insert(std::make_pair(e, nextValueNumber));
+ valueNumbering.insert(std::make_pair(V, nextValueNumber));
+
+ return nextValueNumber++;
+ }
+ } else if (InsertElementInst* U = dyn_cast<InsertElementInst>(V)) {
+ Expression e = create_expression(U);
+
+ DenseMap<Expression, uint32_t>::iterator EI = expressionNumbering.find(e);
+ if (EI != expressionNumbering.end()) {
+ valueNumbering.insert(std::make_pair(V, EI->second));
+ return EI->second;
+ } else {
+ expressionNumbering.insert(std::make_pair(e, nextValueNumber));
+ valueNumbering.insert(std::make_pair(V, nextValueNumber));
+
+ return nextValueNumber++;
+ }
+ } else if (SelectInst* U = dyn_cast<SelectInst>(V)) {
+ Expression e = create_expression(U);
+
+ DenseMap<Expression, uint32_t>::iterator EI = expressionNumbering.find(e);
+ if (EI != expressionNumbering.end()) {
+ valueNumbering.insert(std::make_pair(V, EI->second));
+ return EI->second;
+ } else {
+ expressionNumbering.insert(std::make_pair(e, nextValueNumber));
+ valueNumbering.insert(std::make_pair(V, nextValueNumber));
+
+ return nextValueNumber++;
+ }
+ } else if (CastInst* U = dyn_cast<CastInst>(V)) {
+ Expression e = create_expression(U);
+
+ DenseMap<Expression, uint32_t>::iterator EI = expressionNumbering.find(e);
+ if (EI != expressionNumbering.end()) {
+ valueNumbering.insert(std::make_pair(V, EI->second));
+ return EI->second;
+ } else {
+ expressionNumbering.insert(std::make_pair(e, nextValueNumber));
+ valueNumbering.insert(std::make_pair(V, nextValueNumber));
+
+ return nextValueNumber++;
+ }
+ } else if (GetElementPtrInst* U = dyn_cast<GetElementPtrInst>(V)) {
+ Expression e = create_expression(U);
+
+ DenseMap<Expression, uint32_t>::iterator EI = expressionNumbering.find(e);
+ if (EI != expressionNumbering.end()) {
+ valueNumbering.insert(std::make_pair(V, EI->second));
+ return EI->second;
+ } else {
+ expressionNumbering.insert(std::make_pair(e, nextValueNumber));
+ valueNumbering.insert(std::make_pair(V, nextValueNumber));
+
+ return nextValueNumber++;
+ }
+ } else {
+ valueNumbering.insert(std::make_pair(V, nextValueNumber));
+ return nextValueNumber++;
+ }
+}
+
+/// lookup - Returns the value number of the specified value. Fails if
+/// the value has not yet been numbered.
+uint32_t ValueTable::lookup(Value* V) const {
+ DenseMap<Value*, uint32_t>::iterator VI = valueNumbering.find(V);
+ if (VI != valueNumbering.end())
+ return VI->second;
+ else
+ assert(0 && "Value not numbered?");
+
+ return 0;
+}
+
+/// clear - Remove all entries from the ValueTable
+void ValueTable::clear() {
+ valueNumbering.clear();
+ expressionNumbering.clear();
+ nextValueNumber = 1;
+}
+
+//===----------------------------------------------------------------------===//
+// ValueNumberedSet Class
+//===----------------------------------------------------------------------===//
+namespace {
+class ValueNumberedSet {
+ private:
+ SmallPtrSet<Value*, 8> contents;
+ BitVector numbers;
+ public:
+ ValueNumberedSet() { numbers.resize(1); }
+ ValueNumberedSet(const ValueNumberedSet& other) {
+ numbers = other.numbers;
+ contents = other.contents;
+ }
+
+ typedef SmallPtrSet<Value*, 8>::iterator iterator;
+
+ iterator begin() { return contents.begin(); }
+ iterator end() { return contents.end(); }
+
+ bool insert(Value* v) { return contents.insert(v); }
+ void insert(iterator I, iterator E) { contents.insert(I, E); }
+ void erase(Value* v) { contents.erase(v); }
+ unsigned count(Value* v) { return contents.count(v); }
+ size_t size() { return contents.size(); }
+
+ void set(unsigned i) {
+ if (i >= numbers.size())
+ numbers.resize(i+1);
+
+ numbers.set(i);
+ }
+
+ void operator=(const ValueNumberedSet& other) {
+ contents = other.contents;
+ numbers = other.numbers;
+ }
+
+ void reset(unsigned i) {
+ if (i < numbers.size())
+ numbers.reset(i);
+ }
+
+ bool test(unsigned i) {
+ if (i >= numbers.size())
+ return false;
+
+ return numbers.test(i);
+ }
+
+ void clear() {
+ contents.clear();
+ numbers.clear();
+ }
+};
+}
+
+//===----------------------------------------------------------------------===//
+// GVN Pass
+//===----------------------------------------------------------------------===//
+
+namespace {
+
+ class VISIBILITY_HIDDEN GVN : public FunctionPass {
+ bool runOnFunction(Function &F);
+ public:
+ static char ID; // Pass identification, replacement for typeid
+ GVN() : FunctionPass((intptr_t)&ID) { }
+
+ private:
+ ValueTable VN;
+
+ DenseMap<BasicBlock*, ValueNumberedSet> availableOut;
+
+ // This transformation requires dominator postdominator info
+ virtual void getAnalysisUsage(AnalysisUsage &AU) const {
+ AU.setPreservesCFG();
+ AU.addRequired<DominatorTree>();
+ AU.addRequired<MemoryDependenceAnalysis>();
+ AU.addPreserved<MemoryDependenceAnalysis>();
+ }
+
+ // Helper fuctions
+ // FIXME: eliminate or document these better
+ Value* find_leader(ValueNumberedSet& vals, uint32_t v) ;
+ void val_insert(ValueNumberedSet& s, Value* v);
+ bool processLoad(LoadInst* L,
+ DenseMap<Value*, LoadInst*>& lastLoad,
+ SmallVector<Instruction*, 4>& toErase);
+ bool processInstruction(Instruction* I,
+ ValueNumberedSet& currAvail,
+ DenseMap<Value*, LoadInst*>& lastSeenLoad,
+ SmallVector<Instruction*, 4>& toErase);
+ };
+
+ char GVN::ID = 0;
+
+}
+
+// createGVNPass - The public interface to this file...
+FunctionPass *llvm::createGVNPass() { return new GVN(); }
+
+static RegisterPass<GVN> X("gvn",
+ "Global Value Numbering");
+
+STATISTIC(NumGVNInstr, "Number of instructions deleted");
+STATISTIC(NumGVNLoad, "Number of loads deleted");
+
+/// find_leader - Given a set and a value number, return the first
+/// element of the set with that value number, or 0 if no such element
+/// is present
+Value* GVN::find_leader(ValueNumberedSet& vals, uint32_t v) {
+ if (!vals.test(v))
+ return 0;
+
+ for (ValueNumberedSet::iterator I = vals.begin(), E = vals.end();
+ I != E; ++I)
+ if (v == VN.lookup(*I))
+ return *I;
+
+ assert(0 && "No leader found, but present bit is set?");
+ return 0;
+}
+
+/// val_insert - Insert a value into a set only if there is not a value
+/// with the same value number already in the set
+void GVN::val_insert(ValueNumberedSet& s, Value* v) {
+ uint32_t num = VN.lookup(v);
+ if (!s.test(num))
+ s.insert(v);
+}
+
+bool GVN::processLoad(LoadInst* L,
+ DenseMap<Value*, LoadInst*>& lastLoad,
+ SmallVector<Instruction*, 4>& toErase) {
+ if (L->isVolatile()) {
+ lastLoad[L->getPointerOperand()] = L;
+ return false;
+ }
+
+ Value* pointer = L->getPointerOperand();
+ LoadInst*& last = lastLoad[pointer];
+
+ // ... to a pointer that has been loaded from before...
+ MemoryDependenceAnalysis& MD = getAnalysis<MemoryDependenceAnalysis>();
+ Instruction* dep = MD.getDependency(L);
+ bool deletedLoad = false;
+
+ while (dep != MemoryDependenceAnalysis::None &&
+ dep != MemoryDependenceAnalysis::NonLocal &&
+ (isa<LoadInst>(dep) || isa<StoreInst>(dep))) {
+ // ... that depends on a store ...
+ if (StoreInst* S = dyn_cast<StoreInst>(dep)) {
+ if (S->getPointerOperand() == pointer) {
+ // Remove it!
+ MD.removeInstruction(L);
+
+ L->replaceAllUsesWith(S->getOperand(0));
+ toErase.push_back(L);
+ deletedLoad = true;
+ NumGVNLoad++;
+ }
+
+ // Whether we removed it or not, we can't
+ // go any further
+ break;
+ } else if (!last) {
+ // If we don't depend on a store, and we haven't
+ // been loaded before, bail.
+ break;
+ } else if (dep == last) {
+ // Remove it!
+ MD.removeInstruction(L);
+
+ L->replaceAllUsesWith(last);
+ toErase.push_back(L);
+ deletedLoad = true;
+ NumGVNLoad++;
+
+ break;
+ } else {
+ dep = MD.getDependency(L, dep);
+ }
+ }
+
+ if (!deletedLoad)
+ last = L;
+
+ return deletedLoad;
+}
+
+/// buildsets_availout - When calculating availability, handle an instruction
+/// by inserting it into the appropriate sets
+bool GVN::processInstruction(Instruction* I,
+ ValueNumberedSet& currAvail,
+ DenseMap<Value*, LoadInst*>& lastSeenLoad,
+ SmallVector<Instruction*, 4>& toErase) {
+ if (LoadInst* L = dyn_cast<LoadInst>(I)) {
+ return processLoad(L, lastSeenLoad, toErase);
+ }
+
+ unsigned num = VN.lookup_or_add(I);
+
+ if (currAvail.test(num)) {
+ Value* repl = find_leader(currAvail, num);
+
+ I->replaceAllUsesWith(repl);
+ toErase.push_back(I);
+ return true;
+ } else if (!I->isTerminator()) {
+ currAvail.set(num);
+ currAvail.insert(I);
+ }
+
+ return false;
+}
+
+// GVN::runOnFunction - This is the main transformation entry point for a
+// function.
+//
+bool GVN::runOnFunction(Function &F) {
+ // Clean out global sets from any previous functions
+ VN.clear();
+ availableOut.clear();
+
+ bool changed_function = false;
+
+ DominatorTree &DT = getAnalysis<DominatorTree>();
+
+ SmallVector<Instruction*, 4> toErase;
+
+ // Top-down walk of the dominator tree
+ for (df_iterator<DomTreeNode*> DI = df_begin(DT.getRootNode()),
+ E = df_end(DT.getRootNode()); DI != E; ++DI) {
+
+ // Get the set to update for this block
+ ValueNumberedSet& currAvail = availableOut[DI->getBlock()];
+ DenseMap<Value*, LoadInst*> lastSeenLoad;
+
+ BasicBlock* BB = DI->getBlock();
+
+ // A block inherits AVAIL_OUT from its dominator
+ if (DI->getIDom() != 0)
+ currAvail = availableOut[DI->getIDom()->getBlock()];
+
+ for (BasicBlock::iterator BI = BB->begin(), BE = BB->end();
+ BI != BE; ++BI) {
+ processInstruction(BI, currAvail, lastSeenLoad, toErase);
+ }
+ }
+
+ NumGVNInstr = toErase.size();
+
+ for (SmallVector<Instruction*, 4>::iterator I = toErase.begin(),
+ E = toErase.end(); I != E; ++I)
+ (*I)->eraseFromParent();
+
+ return changed_function;
+}
Added: llvm/trunk/test/Transforms/GVN/basic.ll
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/test/Transforms/GVN/basic.ll?rev=40469&view=auto
==============================================================================
--- llvm/trunk/test/Transforms/GVN/basic.ll (added)
+++ llvm/trunk/test/Transforms/GVN/basic.ll Tue Jul 24 12:55:58 2007
@@ -0,0 +1,10 @@
+; RUN: llvm-as < %s | opt -gvn | llvm-dis | not grep {%z2 =}
+
+define i32 @main() {
+block1:
+ %z1 = bitcast i32 0 to i32
+ br label %block2
+block2:
+ %z2 = bitcast i32 0 to i32
+ ret i32 %z2
+}
\ No newline at end of file
Added: llvm/trunk/test/Transforms/GVN/dg.exp
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/test/Transforms/GVN/dg.exp?rev=40469&view=auto
==============================================================================
--- llvm/trunk/test/Transforms/GVN/dg.exp (added)
+++ llvm/trunk/test/Transforms/GVN/dg.exp Tue Jul 24 12:55:58 2007
@@ -0,0 +1,3 @@
+load_lib llvm.exp
+
+RunLLVMTests [lsort [glob -nocomplain $srcdir/$subdir/*.{ll,llx,c,cpp,tr}]]
Added: llvm/trunk/test/Transforms/GVN/mixed.ll
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/test/Transforms/GVN/mixed.ll?rev=40469&view=auto
==============================================================================
--- llvm/trunk/test/Transforms/GVN/mixed.ll (added)
+++ llvm/trunk/test/Transforms/GVN/mixed.ll Tue Jul 24 12:55:58 2007
@@ -0,0 +1,13 @@
+; RUN: llvm-as < %s | opt -gvn | llvm-dis | not grep DEADLOAD
+; RUN: llvm-as < %s | opt -gvn | llvm-dis | not grep DEADGEP
+
+define i32 @main(i32** %p) {
+block1:
+ %z1 = load i32** %p
+ %z2 = getelementptr i32* %z1, i32 0
+ %z3 = load i32* %z2
+ %DEADLOAD = load i32** %p
+ %DEADGEP = getelementptr i32* %DEADLOAD, i32 0
+ %DEADLOAD2 = load i32* %DEADGEP
+ ret i32 %DEADLOAD2
+}
\ No newline at end of file
More information about the llvm-commits
mailing list