+++ /dev/null
-//===- CorrelatedExprs.cpp - Pass to detect and eliminated c.e.'s ---------===//
-//
-// The LLVM Compiler Infrastructure
-//
-// This file is distributed under the University of Illinois Open Source
-// License. See LICENSE.TXT for details.
-//
-//===----------------------------------------------------------------------===//
-//
-// Correlated Expression Elimination propagates information from conditional
-// branches to blocks dominated by destinations of the branch. It propagates
-// information from the condition check itself into the body of the branch,
-// allowing transformations like these for example:
-//
-// if (i == 7)
-// ... 4*i; // constant propagation
-//
-// M = i+1; N = j+1;
-// if (i == j)
-// X = M-N; // = M-M == 0;
-//
-// This is called Correlated Expression Elimination because we eliminate or
-// simplify expressions that are correlated with the direction of a branch. In
-// this way we use static information to give us some information about the
-// dynamic value of a variable.
-//
-//===----------------------------------------------------------------------===//
-
-#define DEBUG_TYPE "cee"
-#include "llvm/Transforms/Scalar.h"
-#include "llvm/Constants.h"
-#include "llvm/Pass.h"
-#include "llvm/Function.h"
-#include "llvm/Instructions.h"
-#include "llvm/Type.h"
-#include "llvm/DerivedTypes.h"
-#include "llvm/Analysis/ConstantFolding.h"
-#include "llvm/Analysis/Dominators.h"
-#include "llvm/Assembly/Writer.h"
-#include "llvm/Transforms/Utils/BasicBlockUtils.h"
-#include "llvm/Support/CFG.h"
-#include "llvm/Support/Compiler.h"
-#include "llvm/Support/ConstantRange.h"
-#include "llvm/Support/Debug.h"
-#include "llvm/ADT/PostOrderIterator.h"
-#include "llvm/ADT/Statistic.h"
-#include <algorithm>
-using namespace llvm;
-
-STATISTIC(NumCmpRemoved, "Number of cmp instruction eliminated");
-STATISTIC(NumOperandsCann, "Number of operands canonicalized");
-STATISTIC(BranchRevectors, "Number of branches revectored");
-
-namespace {
- class ValueInfo;
- class VISIBILITY_HIDDEN Relation {
- Value *Val; // Relation to what value?
- unsigned Rel; // SetCC or ICmp relation, or Add if no information
- public:
- explicit Relation(Value *V) : Val(V), Rel(Instruction::Add) {}
- bool operator<(const Relation &R) const { return Val < R.Val; }
- Value *getValue() const { return Val; }
- unsigned getRelation() const { return Rel; }
-
- // contradicts - Return true if the relationship specified by the operand
- // contradicts already known information.
- //
- bool contradicts(unsigned Rel, const ValueInfo &VI) const;
-
- // incorporate - Incorporate information in the argument into this relation
- // entry. This assumes that the information doesn't contradict itself. If
- // any new information is gained, true is returned, otherwise false is
- // returned to indicate that nothing was updated.
- //
- bool incorporate(unsigned Rel, ValueInfo &VI);
-
- // KnownResult - Whether or not this condition determines the result of a
- // setcc or icmp in the program. False & True are intentionally 0 & 1
- // so we can convert to bool by casting after checking for unknown.
- //
- enum KnownResult { KnownFalse = 0, KnownTrue = 1, Unknown = 2 };
-
- // getImpliedResult - If this relationship between two values implies that
- // the specified relationship is true or false, return that. If we cannot
- // determine the result required, return Unknown.
- //
- KnownResult getImpliedResult(unsigned Rel) const;
-
- // print - Output this relation to the specified stream
- void print(std::ostream &OS) const;
- void dump() const;
- };
-
-
- // ValueInfo - One instance of this record exists for every value with
- // relationships between other values. It keeps track of all of the
- // relationships to other values in the program (specified with Relation) that
- // are known to be valid in a region.
- //
- class VISIBILITY_HIDDEN ValueInfo {
- // RelationShips - this value is know to have the specified relationships to
- // other values. There can only be one entry per value, and this list is
- // kept sorted by the Val field.
- std::vector<Relation> Relationships;
-
- // If information about this value is known or propagated from constant
- // expressions, this range contains the possible values this value may hold.
- ConstantRange Bounds;
-
- // If we find that this value is equal to another value that has a lower
- // rank, this value is used as it's replacement.
- //
- Value *Replacement;
- public:
- explicit ValueInfo(const Type *Ty)
- : Bounds(Ty->isInteger() ? cast<IntegerType>(Ty)->getBitWidth() : 32),
- Replacement(0) {}
-
- // getBounds() - Return the constant bounds of the value...
- const ConstantRange &getBounds() const { return Bounds; }
- ConstantRange &getBounds() { return Bounds; }
-
- const std::vector<Relation> &getRelationships() { return Relationships; }
-
- // getReplacement - Return the value this value is to be replaced with if it
- // exists, otherwise return null.
- //
- Value *getReplacement() const { return Replacement; }
-
- // setReplacement - Used by the replacement calculation pass to figure out
- // what to replace this value with, if anything.
- //
- void setReplacement(Value *Repl) { Replacement = Repl; }
-
- // getRelation - return the relationship entry for the specified value.
- // This can invalidate references to other Relations, so use it carefully.
- //
- Relation &getRelation(Value *V) {
- // Binary search for V's entry...
- std::vector<Relation>::iterator I =
- std::lower_bound(Relationships.begin(), Relationships.end(),
- Relation(V));
-
- // If we found the entry, return it...
- if (I != Relationships.end() && I->getValue() == V)
- return *I;
-
- // Insert and return the new relationship...
- return *Relationships.insert(I, Relation(V));
- }
-
- const Relation *requestRelation(Value *V) const {
- // Binary search for V's entry...
- std::vector<Relation>::const_iterator I =
- std::lower_bound(Relationships.begin(), Relationships.end(),
- Relation(V));
- if (I != Relationships.end() && I->getValue() == V)
- return &*I;
- return 0;
- }
-
- // print - Output information about this value relation...
- void print(std::ostream &OS, Value *V) const;
- void dump() const;
- };
-
- // RegionInfo - Keeps track of all of the value relationships for a region. A
- // region is the are dominated by a basic block. RegionInfo's keep track of
- // the RegionInfo for their dominator, because anything known in a dominator
- // is known to be true in a dominated block as well.
- //
- class VISIBILITY_HIDDEN RegionInfo {
- BasicBlock *BB;
-
- // ValueMap - Tracks the ValueInformation known for this region
- typedef std::map<Value*, ValueInfo> ValueMapTy;
- ValueMapTy ValueMap;
- public:
- explicit RegionInfo(BasicBlock *bb) : BB(bb) {}
-
- // getEntryBlock - Return the block that dominates all of the members of
- // this region.
- BasicBlock *getEntryBlock() const { return BB; }
-
- // empty - return true if this region has no information known about it.
- bool empty() const { return ValueMap.empty(); }
-
- const RegionInfo &operator=(const RegionInfo &RI) {
- ValueMap = RI.ValueMap;
- return *this;
- }
-
- // print - Output information about this region...
- void print(std::ostream &OS) const;
- void dump() const;
-
- // Allow external access.
- typedef ValueMapTy::iterator iterator;
- iterator begin() { return ValueMap.begin(); }
- iterator end() { return ValueMap.end(); }
-
- ValueInfo &getValueInfo(Value *V) {
- ValueMapTy::iterator I = ValueMap.lower_bound(V);
- if (I != ValueMap.end() && I->first == V) return I->second;
- return ValueMap.insert(I, std::make_pair(V, V->getType()))->second;
- }
-
- const ValueInfo *requestValueInfo(Value *V) const {
- ValueMapTy::const_iterator I = ValueMap.find(V);
- if (I != ValueMap.end()) return &I->second;
- return 0;
- }
-
- /// removeValueInfo - Remove anything known about V from our records. This
- /// works whether or not we know anything about V.
- ///
- void removeValueInfo(Value *V) {
- ValueMap.erase(V);
- }
- };
-
- /// CEE - Correlated Expression Elimination
- class VISIBILITY_HIDDEN CEE : public FunctionPass {
- std::map<Value*, unsigned> RankMap;
- std::map<BasicBlock*, RegionInfo> RegionInfoMap;
- DominatorTree *DT;
- public:
- static char ID; // Pass identification, replacement for typeid
- CEE() : FunctionPass((intptr_t)&ID) {}
-
- virtual bool runOnFunction(Function &F);
-
- // We don't modify the program, so we preserve all analyses
- virtual void getAnalysisUsage(AnalysisUsage &AU) const {
- AU.addRequired<DominatorTree>();
- AU.addRequiredID(BreakCriticalEdgesID);
- };
-
- // print - Implement the standard print form to print out analysis
- // information.
- virtual void print(std::ostream &O, const Module *M) const;
-
- private:
- RegionInfo &getRegionInfo(BasicBlock *BB) {
- std::map<BasicBlock*, RegionInfo>::iterator I
- = RegionInfoMap.lower_bound(BB);
- if (I != RegionInfoMap.end() && I->first == BB) return I->second;
- return RegionInfoMap.insert(I, std::make_pair(BB, BB))->second;
- }
-
- void BuildRankMap(Function &F);
- unsigned getRank(Value *V) const {
- if (isa<Constant>(V)) return 0;
- std::map<Value*, unsigned>::const_iterator I = RankMap.find(V);
- if (I != RankMap.end()) return I->second;
- return 0; // Must be some other global thing
- }
-
- bool TransformRegion(BasicBlock *BB, std::set<BasicBlock*> &VisitedBlocks);
-
- bool ForwardCorrelatedEdgeDestination(TerminatorInst *TI, unsigned SuccNo,
- RegionInfo &RI);
-
- void ForwardSuccessorTo(TerminatorInst *TI, unsigned Succ, BasicBlock *D,
- RegionInfo &RI);
- void ReplaceUsesOfValueInRegion(Value *Orig, Value *New,
- BasicBlock *RegionDominator);
- void CalculateRegionExitBlocks(BasicBlock *BB, BasicBlock *OldSucc,
- std::vector<BasicBlock*> &RegionExitBlocks);
- void InsertRegionExitMerges(PHINode *NewPHI, Instruction *OldVal,
- const std::vector<BasicBlock*> &RegionExitBlocks);
-
- void PropagateBranchInfo(BranchInst *BI);
- void PropagateSwitchInfo(SwitchInst *SI);
- void PropagateEquality(Value *Op0, Value *Op1, RegionInfo &RI);
- void PropagateRelation(unsigned Opcode, Value *Op0,
- Value *Op1, RegionInfo &RI);
- void UpdateUsersOfValue(Value *V, RegionInfo &RI);
- void IncorporateInstruction(Instruction *Inst, RegionInfo &RI);
- void ComputeReplacements(RegionInfo &RI);
-
- // getCmpResult - Given a icmp instruction, determine if the result is
- // determined by facts we already know about the region under analysis.
- // Return KnownTrue, KnownFalse, or UnKnown based on what we can determine.
- Relation::KnownResult getCmpResult(CmpInst *ICI, const RegionInfo &RI);
-
- bool SimplifyBasicBlock(BasicBlock &BB, const RegionInfo &RI);
- bool SimplifyInstruction(Instruction *Inst, const RegionInfo &RI);
- };
-
- char CEE::ID = 0;
- RegisterPass<CEE> X("cee", "Correlated Expression Elimination");
-}
-
-FunctionPass *llvm::createCorrelatedExpressionEliminationPass() {
- return new CEE();
-}
-
-
-bool CEE::runOnFunction(Function &F) {
- // Build a rank map for the function...
- BuildRankMap(F);
-
- // Traverse the dominator tree, computing information for each node in the
- // tree. Note that our traversal will not even touch unreachable basic
- // blocks.
- DT = &getAnalysis<DominatorTree>();
-
- std::set<BasicBlock*> VisitedBlocks;
- bool Changed = TransformRegion(&F.getEntryBlock(), VisitedBlocks);
-
- RegionInfoMap.clear();
- RankMap.clear();
- return Changed;
-}
-
-// TransformRegion - Transform the region starting with BB according to the
-// calculated region information for the block. Transforming the region
-// involves analyzing any information this block provides to successors,
-// propagating the information to successors, and finally transforming
-// successors.
-//
-// This method processes the function in depth first order, which guarantees
-// that we process the immediate dominator of a block before the block itself.
-// Because we are passing information from immediate dominators down to
-// dominatees, we obviously have to process the information source before the
-// information consumer.
-//
-bool CEE::TransformRegion(BasicBlock *BB, std::set<BasicBlock*> &VisitedBlocks){
- // Prevent infinite recursion...
- if (VisitedBlocks.count(BB)) return false;
- VisitedBlocks.insert(BB);
-
- // Get the computed region information for this block...
- RegionInfo &RI = getRegionInfo(BB);
-
- // Compute the replacement information for this block...
- ComputeReplacements(RI);
-
- // If debugging, print computed region information...
- DEBUG(RI.print(*cerr.stream()));
-
- // Simplify the contents of this block...
- bool Changed = SimplifyBasicBlock(*BB, RI);
-
- // Get the terminator of this basic block...
- TerminatorInst *TI = BB->getTerminator();
-
- // Loop over all of the blocks that this block is the immediate dominator for.
- // Because all information known in this region is also known in all of the
- // blocks that are dominated by this one, we can safely propagate the
- // information down now.
- //
- DomTreeNode *BBDom = DT->getNode(BB);
- if (!RI.empty()) { // Time opt: only propagate if we can change something
- for (std::vector<DomTreeNode*>::iterator DI = BBDom->begin(),
- E = BBDom->end(); DI != E; ++DI) {
- BasicBlock *ChildBB = (*DI)->getBlock();
- assert(RegionInfoMap.find(ChildBB) == RegionInfoMap.end() &&
- "RegionInfo should be calculated in dominanace order!");
- getRegionInfo(ChildBB) = RI;
- }
- }
-
- // Now that all of our successors have information if they deserve it,
- // propagate any information our terminator instruction finds to our
- // successors.
- if (BranchInst *BI = dyn_cast<BranchInst>(TI)) {
- if (BI->isConditional())
- PropagateBranchInfo(BI);
- } else if (SwitchInst *SI = dyn_cast<SwitchInst>(TI)) {
- PropagateSwitchInfo(SI);
- }
-
- // If this is a branch to a block outside our region that simply performs
- // another conditional branch, one whose outcome is known inside of this
- // region, then vector this outgoing edge directly to the known destination.
- //
- for (unsigned i = 0, e = TI->getNumSuccessors(); i != e; ++i)
- while (ForwardCorrelatedEdgeDestination(TI, i, RI)) {
- ++BranchRevectors;
- Changed = true;
- }
-
- // Now that all of our successors have information, recursively process them.
- for (std::vector<DomTreeNode*>::iterator DI = BBDom->begin(),
- E = BBDom->end(); DI != E; ++DI) {
- BasicBlock *ChildBB = (*DI)->getBlock();
- Changed |= TransformRegion(ChildBB, VisitedBlocks);
- }
-
- return Changed;
-}
-
-// isBlockSimpleEnoughForCheck to see if the block is simple enough for us to
-// revector the conditional branch in the bottom of the block, do so now.
-//
-static bool isBlockSimpleEnough(BasicBlock *BB) {
- assert(isa<BranchInst>(BB->getTerminator()));
- BranchInst *BI = cast<BranchInst>(BB->getTerminator());
- assert(BI->isConditional());
-
- // Check the common case first: empty block, or block with just a setcc.
- if (BB->size() == 1 ||
- (BB->size() == 2 && &BB->front() == BI->getCondition() &&
- BI->getCondition()->hasOneUse()))
- return true;
-
- // Check the more complex case now...
- BasicBlock::iterator I = BB->begin();
-
- // FIXME: This should be reenabled once the regression with SIM is fixed!
-#if 0
- // PHI Nodes are ok, just skip over them...
- while (isa<PHINode>(*I)) ++I;
-#endif
-
- // Accept the setcc instruction...
- if (&*I == BI->getCondition())
- ++I;
-
- // Nothing else is acceptable here yet. We must not revector... unless we are
- // at the terminator instruction.
- if (&*I == BI)
- return true;
-
- return false;
-}
-
-
-bool CEE::ForwardCorrelatedEdgeDestination(TerminatorInst *TI, unsigned SuccNo,
- RegionInfo &RI) {
- // If this successor is a simple block not in the current region, which
- // contains only a conditional branch, we decide if the outcome of the branch
- // can be determined from information inside of the region. Instead of going
- // to this block, we can instead go to the destination we know is the right
- // target.
- //
-
- // Check to see if we dominate the block. If so, this block will get the
- // condition turned to a constant anyway.
- //
- //if (EF->dominates(RI.getEntryBlock(), BB))
- // return 0;
-
- BasicBlock *BB = TI->getParent();
-
- // Get the destination block of this edge...
- BasicBlock *OldSucc = TI->getSuccessor(SuccNo);
-
- // Make sure that the block ends with a conditional branch and is simple
- // enough for use to be able to revector over.
- BranchInst *BI = dyn_cast<BranchInst>(OldSucc->getTerminator());
- if (BI == 0 || !BI->isConditional() || !isBlockSimpleEnough(OldSucc))
- return false;
-
- // We can only forward the branch over the block if the block ends with a
- // cmp we can determine the outcome for.
- //
- // FIXME: we can make this more generic. Code below already handles more
- // generic case.
- if (!isa<CmpInst>(BI->getCondition()))
- return false;
-
- // Make a new RegionInfo structure so that we can simulate the effect of the
- // PHI nodes in the block we are skipping over...
- //
- RegionInfo NewRI(RI);
-
- // Remove value information for all of the values we are simulating... to make
- // sure we don't have any stale information.
- for (BasicBlock::iterator I = OldSucc->begin(), E = OldSucc->end(); I!=E; ++I)
- if (I->getType() != Type::VoidTy)
- NewRI.removeValueInfo(I);
-
- // Put the newly discovered information into the RegionInfo...
- for (BasicBlock::iterator I = OldSucc->begin(), E = OldSucc->end(); I!=E; ++I)
- if (PHINode *PN = dyn_cast<PHINode>(I)) {
- int OpNum = PN->getBasicBlockIndex(BB);
- assert(OpNum != -1 && "PHI doesn't have incoming edge for predecessor!?");
- PropagateEquality(PN, PN->getIncomingValue(OpNum), NewRI);
- } else if (CmpInst *CI = dyn_cast<CmpInst>(I)) {
- Relation::KnownResult Res = getCmpResult(CI, NewRI);
- if (Res == Relation::Unknown) return false;
- PropagateEquality(CI, ConstantInt::get(Type::Int1Ty, Res), NewRI);
- } else {
- assert(isa<BranchInst>(*I) && "Unexpected instruction type!");
- }
-
- // Compute the facts implied by what we have discovered...
- ComputeReplacements(NewRI);
-
- ValueInfo &PredicateVI = NewRI.getValueInfo(BI->getCondition());
- if (PredicateVI.getReplacement() &&
- isa<Constant>(PredicateVI.getReplacement()) &&
- !isa<GlobalValue>(PredicateVI.getReplacement())) {
- ConstantInt *CB = cast<ConstantInt>(PredicateVI.getReplacement());
-
- // Forward to the successor that corresponds to the branch we will take.
- ForwardSuccessorTo(TI, SuccNo,
- BI->getSuccessor(!CB->getZExtValue()), NewRI);
- return true;
- }
-
- return false;
-}
-
-static Value *getReplacementOrValue(Value *V, RegionInfo &RI) {
- if (const ValueInfo *VI = RI.requestValueInfo(V))
- if (Value *Repl = VI->getReplacement())
- return Repl;
- return V;
-}
-
-/// ForwardSuccessorTo - We have found that we can forward successor # 'SuccNo'
-/// of Terminator 'TI' to the 'Dest' BasicBlock. This method performs the
-/// mechanics of updating SSA information and revectoring the branch.
-///
-void CEE::ForwardSuccessorTo(TerminatorInst *TI, unsigned SuccNo,
- BasicBlock *Dest, RegionInfo &RI) {
- // If there are any PHI nodes in the Dest BB, we must duplicate the entry
- // in the PHI node for the old successor to now include an entry from the
- // current basic block.
- //
- BasicBlock *OldSucc = TI->getSuccessor(SuccNo);
- BasicBlock *BB = TI->getParent();
-
- DOUT << "Forwarding branch in basic block %" << BB->getName()
- << " from block %" << OldSucc->getName() << " to block %"
- << Dest->getName() << "\n"
- << "Before forwarding: " << *BB->getParent();
-
- // Because we know that there cannot be critical edges in the flow graph, and
- // that OldSucc has multiple outgoing edges, this means that Dest cannot have
- // multiple incoming edges.
- //
-#ifndef NDEBUG
- pred_iterator DPI = pred_begin(Dest); ++DPI;
- assert(DPI == pred_end(Dest) && "Critical edge found!!");
-#endif
-
- // Loop over any PHI nodes in the destination, eliminating them, because they
- // may only have one input.
- //
- while (PHINode *PN = dyn_cast<PHINode>(&Dest->front())) {
- assert(PN->getNumIncomingValues() == 1 && "Crit edge found!");
- // Eliminate the PHI node
- PN->replaceAllUsesWith(PN->getIncomingValue(0));
- Dest->getInstList().erase(PN);
- }
-
- // If there are values defined in the "OldSucc" basic block, we need to insert
- // PHI nodes in the regions we are dealing with to emulate them. This can
- // insert dead phi nodes, but it is more trouble to see if they are used than
- // to just blindly insert them.
- //
- if (DT->dominates(OldSucc, Dest)) {
- // RegionExitBlocks - Find all of the blocks that are not dominated by Dest,
- // but have predecessors that are. Additionally, prune down the set to only
- // include blocks that are dominated by OldSucc as well.
- //
- std::vector<BasicBlock*> RegionExitBlocks;
- CalculateRegionExitBlocks(Dest, OldSucc, RegionExitBlocks);
-
- for (BasicBlock::iterator I = OldSucc->begin(), E = OldSucc->end();
- I != E; ++I)
- if (I->getType() != Type::VoidTy) {
- // Create and insert the PHI node into the top of Dest.
- PHINode *NewPN = new PHINode(I->getType(), I->getName()+".fw_merge",
- Dest->begin());
- // There is definitely an edge from OldSucc... add the edge now
- NewPN->addIncoming(I, OldSucc);
-
- // There is also an edge from BB now, add the edge with the calculated
- // value from the RI.
- NewPN->addIncoming(getReplacementOrValue(I, RI), BB);
-
- // Make everything in the Dest region use the new PHI node now...
- ReplaceUsesOfValueInRegion(I, NewPN, Dest);
-
- // Make sure that exits out of the region dominated by NewPN get PHI
- // nodes that merge the values as appropriate.
- InsertRegionExitMerges(NewPN, I, RegionExitBlocks);
- }
- }
-
- // If there were PHI nodes in OldSucc, we need to remove the entry for this
- // edge from the PHI node, and we need to replace any references to the PHI
- // node with a new value.
- //
- for (BasicBlock::iterator I = OldSucc->begin(); isa<PHINode>(I); ) {
- PHINode *PN = cast<PHINode>(I);
-
- // Get the value flowing across the old edge and remove the PHI node entry
- // for this edge: we are about to remove the edge! Don't remove the PHI
- // node yet though if this is the last edge into it.
- Value *EdgeValue = PN->removeIncomingValue(BB, false);
-
- // Make sure that anything that used to use PN now refers to EdgeValue
- ReplaceUsesOfValueInRegion(PN, EdgeValue, Dest);
-
- // If there is only one value left coming into the PHI node, replace the PHI
- // node itself with the one incoming value left.
- //
- if (PN->getNumIncomingValues() == 1) {
- assert(PN->getNumIncomingValues() == 1);
- PN->replaceAllUsesWith(PN->getIncomingValue(0));
- PN->getParent()->getInstList().erase(PN);
- I = OldSucc->begin();
- } else if (PN->getNumIncomingValues() == 0) { // Nuke the PHI
- // If we removed the last incoming value to this PHI, nuke the PHI node
- // now.
- PN->replaceAllUsesWith(Constant::getNullValue(PN->getType()));
- PN->getParent()->getInstList().erase(PN);
- I = OldSucc->begin();
- } else {
- ++I; // Otherwise, move on to the next PHI node
- }
- }
-
- // Actually revector the branch now...
- TI->setSuccessor(SuccNo, Dest);
-
- // If we just introduced a critical edge in the flow graph, make sure to break
- // it right away...
- SplitCriticalEdge(TI, SuccNo, this);
-
- // Make sure that we don't introduce critical edges from oldsucc now!
- for (unsigned i = 0, e = OldSucc->getTerminator()->getNumSuccessors();
- i != e; ++i)
- SplitCriticalEdge(OldSucc->getTerminator(), i, this);
-
- // Since we invalidated the CFG, recalculate the dominator set so that it is
- // useful for later processing!
- // FIXME: This is much worse than it really should be!
- //EF->recalculate();
-
- DOUT << "After forwarding: " << *BB->getParent();
-}
-
-/// ReplaceUsesOfValueInRegion - This method replaces all uses of Orig with uses
-/// of New. It only affects instructions that are defined in basic blocks that
-/// are dominated by Head.
-///
-void CEE::ReplaceUsesOfValueInRegion(Value *Orig, Value *New,
- BasicBlock *RegionDominator) {
- assert(Orig != New && "Cannot replace value with itself");
- std::vector<Instruction*> InstsToChange;
- std::vector<PHINode*> PHIsToChange;
- InstsToChange.reserve(Orig->getNumUses());
-
- // Loop over instructions adding them to InstsToChange vector, this allows us
- // an easy way to avoid invalidating the use_iterator at a bad time.
- for (Value::use_iterator I = Orig->use_begin(), E = Orig->use_end();
- I != E; ++I)
- if (Instruction *User = dyn_cast<Instruction>(*I))
- if (DT->dominates(RegionDominator, User->getParent()))
- InstsToChange.push_back(User);
- else if (PHINode *PN = dyn_cast<PHINode>(User)) {
- PHIsToChange.push_back(PN);
- }
-
- // PHIsToChange contains PHI nodes that use Orig that do not live in blocks
- // dominated by orig. If the block the value flows in from is dominated by
- // RegionDominator, then we rewrite the PHI
- for (unsigned i = 0, e = PHIsToChange.size(); i != e; ++i) {
- PHINode *PN = PHIsToChange[i];
- for (unsigned j = 0, e = PN->getNumIncomingValues(); j != e; ++j)
- if (PN->getIncomingValue(j) == Orig &&
- DT->dominates(RegionDominator, PN->getIncomingBlock(j)))
- PN->setIncomingValue(j, New);
- }
-
- // Loop over the InstsToChange list, replacing all uses of Orig with uses of
- // New. This list contains all of the instructions in our region that use
- // Orig.
- for (unsigned i = 0, e = InstsToChange.size(); i != e; ++i)
- if (PHINode *PN = dyn_cast<PHINode>(InstsToChange[i])) {
- // PHINodes must be handled carefully. If the PHI node itself is in the
- // region, we have to make sure to only do the replacement for incoming
- // values that correspond to basic blocks in the region.
- for (unsigned j = 0, e = PN->getNumIncomingValues(); j != e; ++j)
- if (PN->getIncomingValue(j) == Orig &&
- DT->dominates(RegionDominator, PN->getIncomingBlock(j)))
- PN->setIncomingValue(j, New);
-
- } else {
- InstsToChange[i]->replaceUsesOfWith(Orig, New);
- }
-}
-
-static void CalcRegionExitBlocks(BasicBlock *Header, BasicBlock *BB,
- std::set<BasicBlock*> &Visited,
- DominatorTree &DT,
- std::vector<BasicBlock*> &RegionExitBlocks) {
- if (Visited.count(BB)) return;
- Visited.insert(BB);
-
- if (DT.dominates(Header, BB)) { // Block in the region, recursively traverse
- for (succ_iterator I = succ_begin(BB), E = succ_end(BB); I != E; ++I)
- CalcRegionExitBlocks(Header, *I, Visited, DT, RegionExitBlocks);
- } else {
- // Header does not dominate this block, but we have a predecessor that does
- // dominate us. Add ourself to the list.
- RegionExitBlocks.push_back(BB);
- }
-}
-
-/// CalculateRegionExitBlocks - Find all of the blocks that are not dominated by
-/// BB, but have predecessors that are. Additionally, prune down the set to
-/// only include blocks that are dominated by OldSucc as well.
-///
-void CEE::CalculateRegionExitBlocks(BasicBlock *BB, BasicBlock *OldSucc,
- std::vector<BasicBlock*> &RegionExitBlocks){
- std::set<BasicBlock*> Visited; // Don't infinite loop
-
- // Recursively calculate blocks we are interested in...
- CalcRegionExitBlocks(BB, BB, Visited, *DT, RegionExitBlocks);
-
- // Filter out blocks that are not dominated by OldSucc...
- for (unsigned i = 0; i != RegionExitBlocks.size(); ) {
- if (DT->dominates(OldSucc, RegionExitBlocks[i]))
- ++i; // Block is ok, keep it.
- else {
- // Move to end of list...
- std::swap(RegionExitBlocks[i], RegionExitBlocks.back());
- RegionExitBlocks.pop_back(); // Nuke the end
- }
- }
-}
-
-void CEE::InsertRegionExitMerges(PHINode *BBVal, Instruction *OldVal,
- const std::vector<BasicBlock*> &RegionExitBlocks) {
- assert(BBVal->getType() == OldVal->getType() && "Should be derived values!");
- BasicBlock *BB = BBVal->getParent();
-
- // Loop over all of the blocks we have to place PHIs in, doing it.
- for (unsigned i = 0, e = RegionExitBlocks.size(); i != e; ++i) {
- BasicBlock *FBlock = RegionExitBlocks[i]; // Block on the frontier
-
- // Create the new PHI node
- PHINode *NewPN = new PHINode(BBVal->getType(),
- OldVal->getName()+".fw_frontier",
- FBlock->begin());
-
- // Add an incoming value for every predecessor of the block...
- for (pred_iterator PI = pred_begin(FBlock), PE = pred_end(FBlock);
- PI != PE; ++PI) {
- // If the incoming edge is from the region dominated by BB, use BBVal,
- // otherwise use OldVal.
- NewPN->addIncoming(DT->dominates(BB, *PI) ? BBVal : OldVal, *PI);
- }
-
- // Now make everyone dominated by this block use this new value!
- ReplaceUsesOfValueInRegion(OldVal, NewPN, FBlock);
- }
-}
-
-
-
-// BuildRankMap - This method builds the rank map data structure which gives
-// each instruction/value in the function a value based on how early it appears
-// in the function. We give constants and globals rank 0, arguments are
-// numbered starting at one, and instructions are numbered in reverse post-order
-// from where the arguments leave off. This gives instructions in loops higher
-// values than instructions not in loops.
-//
-void CEE::BuildRankMap(Function &F) {
- unsigned Rank = 1; // Skip rank zero.
-
- // Number the arguments...
- for (Function::arg_iterator I = F.arg_begin(), E = F.arg_end(); I != E; ++I)
- RankMap[I] = Rank++;
-
- // Number the instructions in reverse post order...
- ReversePostOrderTraversal<Function*> RPOT(&F);
- for (ReversePostOrderTraversal<Function*>::rpo_iterator I = RPOT.begin(),
- E = RPOT.end(); I != E; ++I)
- for (BasicBlock::iterator BBI = (*I)->begin(), E = (*I)->end();
- BBI != E; ++BBI)
- if (BBI->getType() != Type::VoidTy)
- RankMap[BBI] = Rank++;
-}
-
-
-// PropagateBranchInfo - When this method is invoked, we need to propagate
-// information derived from the branch condition into the true and false
-// branches of BI. Since we know that there aren't any critical edges in the
-// flow graph, this can proceed unconditionally.
-//
-void CEE::PropagateBranchInfo(BranchInst *BI) {
- assert(BI->isConditional() && "Must be a conditional branch!");
-
- // Propagate information into the true block...
- //
- PropagateEquality(BI->getCondition(), ConstantInt::getTrue(),
- getRegionInfo(BI->getSuccessor(0)));
-
- // Propagate information into the false block...
- //
- PropagateEquality(BI->getCondition(), ConstantInt::getFalse(),
- getRegionInfo(BI->getSuccessor(1)));
-}
-
-
-// PropagateSwitchInfo - We need to propagate the value tested by the
-// switch statement through each case block.
-//
-void CEE::PropagateSwitchInfo(SwitchInst *SI) {
- // Propagate information down each of our non-default case labels. We
- // don't yet propagate information down the default label, because a
- // potentially large number of inequality constraints provide less
- // benefit per unit work than a single equality constraint.
- //
- Value *cond = SI->getCondition();
- for (unsigned i = 1; i < SI->getNumSuccessors(); ++i)
- PropagateEquality(cond, SI->getSuccessorValue(i),
- getRegionInfo(SI->getSuccessor(i)));
-}
-
-
-// PropagateEquality - If we discover that two values are equal to each other in
-// a specified region, propagate this knowledge recursively.
-//
-void CEE::PropagateEquality(Value *Op0, Value *Op1, RegionInfo &RI) {
- if (Op0 == Op1) return; // Gee whiz. Are these really equal each other?
-
- if (isa<Constant>(Op0)) // Make sure the constant is always Op1
- std::swap(Op0, Op1);
-
- // Make sure we don't already know these are equal, to avoid infinite loops...
- ValueInfo &VI = RI.getValueInfo(Op0);
-
- // Get information about the known relationship between Op0 & Op1
- Relation &KnownRelation = VI.getRelation(Op1);
-
- // If we already know they're equal, don't reprocess...
- if (KnownRelation.getRelation() == FCmpInst::FCMP_OEQ ||
- KnownRelation.getRelation() == ICmpInst::ICMP_EQ)
- return;
-
- // If this is boolean, check to see if one of the operands is a constant. If
- // it's a constant, then see if the other one is one of a setcc instruction,
- // an AND, OR, or XOR instruction.
- //
- ConstantInt *CB = dyn_cast<ConstantInt>(Op1);
- if (CB && Op1->getType() == Type::Int1Ty) {
- if (Instruction *Inst = dyn_cast<Instruction>(Op0)) {
- // If we know that this instruction is an AND instruction, and the
- // result is true, this means that both operands to the OR are known
- // to be true as well.
- //
- if (CB->getZExtValue() && Inst->getOpcode() == Instruction::And) {
- PropagateEquality(Inst->getOperand(0), CB, RI);
- PropagateEquality(Inst->getOperand(1), CB, RI);
- }
-
- // If we know that this instruction is an OR instruction, and the result
- // is false, this means that both operands to the OR are know to be
- // false as well.
- //
- if (!CB->getZExtValue() && Inst->getOpcode() == Instruction::Or) {
- PropagateEquality(Inst->getOperand(0), CB, RI);
- PropagateEquality(Inst->getOperand(1), CB, RI);
- }
-
- // If we know that this instruction is a NOT instruction, we know that
- // the operand is known to be the inverse of whatever the current
- // value is.
- //
- if (BinaryOperator *BOp = dyn_cast<BinaryOperator>(Inst))
- if (BinaryOperator::isNot(BOp))
- PropagateEquality(BinaryOperator::getNotArgument(BOp),
- ConstantInt::get(Type::Int1Ty,
- !CB->getZExtValue()), RI);
-
- // If we know the value of a FCmp instruction, propagate the information
- // about the relation into this region as well.
- //
- if (FCmpInst *FCI = dyn_cast<FCmpInst>(Inst)) {
- if (CB->getZExtValue()) { // If we know the condition is true...
- // Propagate info about the LHS to the RHS & RHS to LHS
- PropagateRelation(FCI->getPredicate(), FCI->getOperand(0),
- FCI->getOperand(1), RI);
- PropagateRelation(FCI->getSwappedPredicate(),
- FCI->getOperand(1), FCI->getOperand(0), RI);
-
- } else { // If we know the condition is false...
- // We know the opposite of the condition is true...
- FCmpInst::Predicate C = FCI->getInversePredicate();
-
- PropagateRelation(C, FCI->getOperand(0), FCI->getOperand(1), RI);
- PropagateRelation(FCmpInst::getSwappedPredicate(C),
- FCI->getOperand(1), FCI->getOperand(0), RI);
- }
- }
-
- // If we know the value of a ICmp instruction, propagate the information
- // about the relation into this region as well.
- //
- if (ICmpInst *ICI = dyn_cast<ICmpInst>(Inst)) {
- if (CB->getZExtValue()) { // If we know the condition is true...
- // Propagate info about the LHS to the RHS & RHS to LHS
- PropagateRelation(ICI->getPredicate(), ICI->getOperand(0),
- ICI->getOperand(1), RI);
- PropagateRelation(ICI->getSwappedPredicate(), ICI->getOperand(1),
- ICI->getOperand(1), RI);
-
- } else { // If we know the condition is false ...
- // We know the opposite of the condition is true...
- ICmpInst::Predicate C = ICI->getInversePredicate();
-
- PropagateRelation(C, ICI->getOperand(0), ICI->getOperand(1), RI);
- PropagateRelation(ICmpInst::getSwappedPredicate(C),
- ICI->getOperand(1), ICI->getOperand(0), RI);
- }
- }
- }
- }
-
- // Propagate information about Op0 to Op1 & visa versa
- PropagateRelation(ICmpInst::ICMP_EQ, Op0, Op1, RI);
- PropagateRelation(ICmpInst::ICMP_EQ, Op1, Op0, RI);
- PropagateRelation(FCmpInst::FCMP_OEQ, Op0, Op1, RI);
- PropagateRelation(FCmpInst::FCMP_OEQ, Op1, Op0, RI);
-}
-
-
-// PropagateRelation - We know that the specified relation is true in all of the
-// blocks in the specified region. Propagate the information about Op0 and
-// anything derived from it into this region.
-//
-void CEE::PropagateRelation(unsigned Opcode, Value *Op0,
- Value *Op1, RegionInfo &RI) {
- assert(Op0->getType() == Op1->getType() && "Equal types expected!");
-
- // Constants are already pretty well understood. We will apply information
- // about the constant to Op1 in another call to PropagateRelation.
- //
- if (isa<Constant>(Op0)) return;
-
- // Get the region information for this block to update...
- ValueInfo &VI = RI.getValueInfo(Op0);
-
- // Get information about the known relationship between Op0 & Op1
- Relation &Op1R = VI.getRelation(Op1);
-
- // Quick bailout for common case if we are reprocessing an instruction...
- if (Op1R.getRelation() == Opcode)
- return;
-
- // If we already have information that contradicts the current information we
- // are propagating, ignore this info. Something bad must have happened!
- //
- if (Op1R.contradicts(Opcode, VI)) {
- Op1R.contradicts(Opcode, VI);
- cerr << "Contradiction found for opcode: "
- << ((isa<ICmpInst>(Op0)||isa<ICmpInst>(Op1)) ?
- Instruction::getOpcodeName(Instruction::ICmp) :
- Instruction::getOpcodeName(Opcode))
- << "\n";
- Op1R.print(*cerr.stream());
- return;
- }
-
- // If the information propagated is new, then we want process the uses of this
- // instruction to propagate the information down to them.
- //
- if (Op1R.incorporate(Opcode, VI))
- UpdateUsersOfValue(Op0, RI);
-}
-
-
-// UpdateUsersOfValue - The information about V in this region has been updated.
-// Propagate this to all consumers of the value.
-//
-void CEE::UpdateUsersOfValue(Value *V, RegionInfo &RI) {
- for (Value::use_iterator I = V->use_begin(), E = V->use_end();
- I != E; ++I)
- if (Instruction *Inst = dyn_cast<Instruction>(*I)) {
- // If this is an instruction using a value that we know something about,
- // try to propagate information to the value produced by the
- // instruction. We can only do this if it is an instruction we can
- // propagate information for (a setcc for example), and we only WANT to
- // do this if the instruction dominates this region.
- //
- // If the instruction doesn't dominate this region, then it cannot be
- // used in this region and we don't care about it. If the instruction
- // is IN this region, then we will simplify the instruction before we
- // get to uses of it anyway, so there is no reason to bother with it
- // here. This check is also effectively checking to make sure that Inst
- // is in the same function as our region (in case V is a global f.e.).
- //
- if (DT->properlyDominates(Inst->getParent(), RI.getEntryBlock()))
- IncorporateInstruction(Inst, RI);
- }
-}
-
-// IncorporateInstruction - We just updated the information about one of the
-// operands to the specified instruction. Update the information about the
-// value produced by this instruction
-//
-void CEE::IncorporateInstruction(Instruction *Inst, RegionInfo &RI) {
- if (CmpInst *CI = dyn_cast<CmpInst>(Inst)) {
- // See if we can figure out a result for this instruction...
- Relation::KnownResult Result = getCmpResult(CI, RI);
- if (Result != Relation::Unknown) {
- PropagateEquality(CI, ConstantInt::get(Type::Int1Ty, Result != 0), RI);
- }
- }
-}
-
-
-// ComputeReplacements - Some values are known to be equal to other values in a
-// region. For example if there is a comparison of equality between a variable
-// X and a constant C, we can replace all uses of X with C in the region we are
-// interested in. We generalize this replacement to replace variables with
-// other variables if they are equal and there is a variable with lower rank
-// than the current one. This offers a canonicalizing property that exposes
-// more redundancies for later transformations to take advantage of.
-//
-void CEE::ComputeReplacements(RegionInfo &RI) {
- // Loop over all of the values in the region info map...
- for (RegionInfo::iterator I = RI.begin(), E = RI.end(); I != E; ++I) {
- ValueInfo &VI = I->second;
-
- // If we know that this value is a particular constant, set Replacement to
- // the constant...
- Value *Replacement = 0;
- const APInt * Rplcmnt = VI.getBounds().getSingleElement();
- if (Rplcmnt)
- Replacement = ConstantInt::get(*Rplcmnt);
-
- // If this value is not known to be some constant, figure out the lowest
- // rank value that it is known to be equal to (if anything).
- //
- if (Replacement == 0) {
- // Find out if there are any equality relationships with values of lower
- // rank than VI itself...
- unsigned MinRank = getRank(I->first);
-
- // Loop over the relationships known about Op0.
- const std::vector<Relation> &Relationships = VI.getRelationships();
- for (unsigned i = 0, e = Relationships.size(); i != e; ++i)
- if (Relationships[i].getRelation() == FCmpInst::FCMP_OEQ) {
- unsigned R = getRank(Relationships[i].getValue());
- if (R < MinRank) {
- MinRank = R;
- Replacement = Relationships[i].getValue();
- }
- }
- else if (Relationships[i].getRelation() == ICmpInst::ICMP_EQ) {
- unsigned R = getRank(Relationships[i].getValue());
- if (R < MinRank) {
- MinRank = R;
- Replacement = Relationships[i].getValue();
- }
- }
- }
-
- // If we found something to replace this value with, keep track of it.
- if (Replacement)
- VI.setReplacement(Replacement);
- }
-}
-
-// SimplifyBasicBlock - Given information about values in region RI, simplify
-// the instructions in the specified basic block.
-//
-bool CEE::SimplifyBasicBlock(BasicBlock &BB, const RegionInfo &RI) {
- bool Changed = false;
- for (BasicBlock::iterator I = BB.begin(), E = BB.end(); I != E; ) {
- Instruction *Inst = I++;
-
- // Convert instruction arguments to canonical forms...
- Changed |= SimplifyInstruction(Inst, RI);
-
- if (CmpInst *CI = dyn_cast<CmpInst>(Inst)) {
- // Try to simplify a setcc instruction based on inherited information
- Relation::KnownResult Result = getCmpResult(CI, RI);
- if (Result != Relation::Unknown) {
- DEBUG(cerr << "Replacing icmp with " << Result
- << " constant: " << *CI);
-
- CI->replaceAllUsesWith(ConstantInt::get(Type::Int1Ty, (bool)Result));
- // The instruction is now dead, remove it from the program.
- CI->getParent()->getInstList().erase(CI);
- ++NumCmpRemoved;
- Changed = true;
- }
- }
- }
-
- return Changed;
-}
-
-// SimplifyInstruction - Inspect the operands of the instruction, converting
-// them to their canonical form if possible. This takes care of, for example,
-// replacing a value 'X' with a constant 'C' if the instruction in question is
-// dominated by a true seteq 'X', 'C'.
-//
-bool CEE::SimplifyInstruction(Instruction *I, const RegionInfo &RI) {
- bool Changed = false;
-
- for (unsigned i = 0, e = I->getNumOperands(); i != e; ++i)
- if (const ValueInfo *VI = RI.requestValueInfo(I->getOperand(i)))
- if (Value *Repl = VI->getReplacement()) {
- // If we know if a replacement with lower rank than Op0, make the
- // replacement now.
- DOUT << "In Inst: " << *I << " Replacing operand #" << i
- << " with " << *Repl << "\n";
- I->setOperand(i, Repl);
- Changed = true;
- ++NumOperandsCann;
- }
-
- return Changed;
-}
-
-// getCmpResult - Try to simplify a cmp instruction based on information
-// inherited from a dominating icmp instruction. V is one of the operands to
-// the icmp instruction, and VI is the set of information known about it. We
-// take two cases into consideration here. If the comparison is against a
-// constant value, we can use the constant range to see if the comparison is
-// possible to succeed. If it is not a comparison against a constant, we check
-// to see if there is a known relationship between the two values. If so, we
-// may be able to eliminate the check.
-//
-Relation::KnownResult CEE::getCmpResult(CmpInst *CI,
- const RegionInfo &RI) {
- Value *Op0 = CI->getOperand(0), *Op1 = CI->getOperand(1);
- unsigned short predicate = CI->getPredicate();
-
- if (isa<Constant>(Op0)) {
- if (isa<Constant>(Op1)) {
- if (Constant *Result = ConstantFoldInstruction(CI)) {
- // Wow, this is easy, directly eliminate the ICmpInst.
- DEBUG(cerr << "Replacing cmp with constant fold: " << *CI);
- return cast<ConstantInt>(Result)->getZExtValue()
- ? Relation::KnownTrue : Relation::KnownFalse;
- }
- } else {
- // We want to swap this instruction so that operand #0 is the constant.
- std::swap(Op0, Op1);
- if (isa<ICmpInst>(CI))
- predicate = cast<ICmpInst>(CI)->getSwappedPredicate();
- else
- predicate = cast<FCmpInst>(CI)->getSwappedPredicate();
- }
- }
-
- // Try to figure out what the result of this comparison will be...
- Relation::KnownResult Result = Relation::Unknown;
-
- // We have to know something about the relationship to prove anything...
- if (const ValueInfo *Op0VI = RI.requestValueInfo(Op0)) {
-
- // At this point, we know that if we have a constant argument that it is in
- // Op1. Check to see if we know anything about comparing value with a
- // constant, and if we can use this info to fold the icmp.
- //
- if (ConstantInt *C = dyn_cast<ConstantInt>(Op1)) {
- // Check to see if we already know the result of this comparison...
- ICmpInst::Predicate ipred = ICmpInst::Predicate(predicate);
- ConstantRange R = ICmpInst::makeConstantRange(ipred, C->getValue());
- ConstantRange Int = R.intersectWith(Op0VI->getBounds());
-
- // If the intersection of the two ranges is empty, then the condition
- // could never be true!
- //
- if (Int.isEmptySet()) {
- Result = Relation::KnownFalse;
-
- // Otherwise, if VI.getBounds() (the possible values) is a subset of R
- // (the allowed values) then we know that the condition must always be
- // true!
- //
- } else if (Int == Op0VI->getBounds()) {
- Result = Relation::KnownTrue;
- }
- } else {
- // If we are here, we know that the second argument is not a constant
- // integral. See if we know anything about Op0 & Op1 that allows us to
- // fold this anyway.
- //
- // Do we have value information about Op0 and a relation to Op1?
- if (const Relation *Op2R = Op0VI->requestRelation(Op1))
- Result = Op2R->getImpliedResult(predicate);
- }
- }
- return Result;
-}
-
-//===----------------------------------------------------------------------===//
-// Relation Implementation
-//===----------------------------------------------------------------------===//
-
-// contradicts - Return true if the relationship specified by the operand
-// contradicts already known information.
-//
-bool Relation::contradicts(unsigned Op,
- const ValueInfo &VI) const {
- assert (Op != Instruction::Add && "Invalid relation argument!");
-
- // If this is a relationship with a constant, make sure that this relationship
- // does not contradict properties known about the bounds of the constant.
- //
- if (ConstantInt *C = dyn_cast<ConstantInt>(Val))
- if (Op >= ICmpInst::FIRST_ICMP_PREDICATE &&
- Op <= ICmpInst::LAST_ICMP_PREDICATE) {
- ICmpInst::Predicate ipred = ICmpInst::Predicate(Op);
- if (ICmpInst::makeConstantRange(ipred, C->getValue())
- .intersectWith(VI.getBounds()).isEmptySet())
- return true;
- }
-
- switch (Rel) {
- default: assert(0 && "Unknown Relationship code!");
- case Instruction::Add: return false; // Nothing known, nothing contradicts
- case ICmpInst::ICMP_EQ:
- return Op == ICmpInst::ICMP_ULT || Op == ICmpInst::ICMP_SLT ||
- Op == ICmpInst::ICMP_UGT || Op == ICmpInst::ICMP_SGT ||
- Op == ICmpInst::ICMP_NE;
- case ICmpInst::ICMP_NE: return Op == ICmpInst::ICMP_EQ;
- case ICmpInst::ICMP_ULE:
- case ICmpInst::ICMP_SLE: return Op == ICmpInst::ICMP_UGT ||
- Op == ICmpInst::ICMP_SGT;
- case ICmpInst::ICMP_UGE:
- case ICmpInst::ICMP_SGE: return Op == ICmpInst::ICMP_ULT ||
- Op == ICmpInst::ICMP_SLT;
- case ICmpInst::ICMP_ULT:
- case ICmpInst::ICMP_SLT:
- return Op == ICmpInst::ICMP_EQ || Op == ICmpInst::ICMP_UGT ||
- Op == ICmpInst::ICMP_SGT || Op == ICmpInst::ICMP_UGE ||
- Op == ICmpInst::ICMP_SGE;
- case ICmpInst::ICMP_UGT:
- case ICmpInst::ICMP_SGT:
- return Op == ICmpInst::ICMP_EQ || Op == ICmpInst::ICMP_ULT ||
- Op == ICmpInst::ICMP_SLT || Op == ICmpInst::ICMP_ULE ||
- Op == ICmpInst::ICMP_SLE;
- case FCmpInst::FCMP_OEQ:
- return Op == FCmpInst::FCMP_OLT || Op == FCmpInst::FCMP_OGT ||
- Op == FCmpInst::FCMP_ONE;
- case FCmpInst::FCMP_ONE: return Op == FCmpInst::FCMP_OEQ;
- case FCmpInst::FCMP_OLE: return Op == FCmpInst::FCMP_OGT;
- case FCmpInst::FCMP_OGE: return Op == FCmpInst::FCMP_OLT;
- case FCmpInst::FCMP_OLT:
- return Op == FCmpInst::FCMP_OEQ || Op == FCmpInst::FCMP_OGT ||
- Op == FCmpInst::FCMP_OGE;
- case FCmpInst::FCMP_OGT:
- return Op == FCmpInst::FCMP_OEQ || Op == FCmpInst::FCMP_OLT ||
- Op == FCmpInst::FCMP_OLE;
- }
-}
-
-// incorporate - Incorporate information in the argument into this relation
-// entry. This assumes that the information doesn't contradict itself. If any
-// new information is gained, true is returned, otherwise false is returned to
-// indicate that nothing was updated.
-//
-bool Relation::incorporate(unsigned Op, ValueInfo &VI) {
- assert(!contradicts(Op, VI) &&
- "Cannot incorporate contradictory information!");
-
- // If this is a relationship with a constant, make sure that we update the
- // range that is possible for the value to have...
- //
- if (ConstantInt *C = dyn_cast<ConstantInt>(Val))
- if (Op >= ICmpInst::FIRST_ICMP_PREDICATE &&
- Op <= ICmpInst::LAST_ICMP_PREDICATE) {
- ICmpInst::Predicate ipred = ICmpInst::Predicate(Op);
- VI.getBounds() =
- ICmpInst::makeConstantRange(ipred, C->getValue())
- .intersectWith(VI.getBounds());
- }
-
- switch (Rel) {
- default: assert(0 && "Unknown prior value!");
- case Instruction::Add: Rel = Op; return true;
- case ICmpInst::ICMP_EQ:
- case ICmpInst::ICMP_NE:
- case ICmpInst::ICMP_ULT:
- case ICmpInst::ICMP_SLT:
- case ICmpInst::ICMP_UGT:
- case ICmpInst::ICMP_SGT: return false; // Nothing is more precise
- case ICmpInst::ICMP_ULE:
- case ICmpInst::ICMP_SLE:
- if (Op == ICmpInst::ICMP_EQ || Op == ICmpInst::ICMP_ULT ||
- Op == ICmpInst::ICMP_SLT) {
- Rel = Op;
- return true;
- } else if (Op == ICmpInst::ICMP_NE) {
- Rel = Rel == ICmpInst::ICMP_ULE ? ICmpInst::ICMP_ULT :
- ICmpInst::ICMP_SLT;
- return true;
- }
- return false;
- case ICmpInst::ICMP_UGE:
- case ICmpInst::ICMP_SGE:
- if (Op == ICmpInst::ICMP_EQ || ICmpInst::ICMP_UGT ||
- Op == ICmpInst::ICMP_SGT) {
- Rel = Op;
- return true;
- } else if (Op == ICmpInst::ICMP_NE) {
- Rel = Rel == ICmpInst::ICMP_UGE ? ICmpInst::ICMP_UGT :
- ICmpInst::ICMP_SGT;
- return true;
- }
- return false;
- case FCmpInst::FCMP_OEQ: return false; // Nothing is more precise
- case FCmpInst::FCMP_ONE: return false; // Nothing is more precise
- case FCmpInst::FCMP_OLT: return false; // Nothing is more precise
- case FCmpInst::FCMP_OGT: return false; // Nothing is more precise
- case FCmpInst::FCMP_OLE:
- if (Op == FCmpInst::FCMP_OEQ || Op == FCmpInst::FCMP_OLT) {
- Rel = Op;
- return true;
- } else if (Op == FCmpInst::FCMP_ONE) {
- Rel = FCmpInst::FCMP_OLT;
- return true;
- }
- return false;
- case FCmpInst::FCMP_OGE:
- if (Op == FCmpInst::FCMP_OEQ || Op == FCmpInst::FCMP_OGT) {
- Rel = Op;
- return true;
- } else if (Op == FCmpInst::FCMP_ONE) {
- Rel = FCmpInst::FCMP_OGT;
- return true;
- }
- return false;
- }
-}
-
-// getImpliedResult - If this relationship between two values implies that
-// the specified relationship is true or false, return that. If we cannot
-// determine the result required, return Unknown.
-//
-Relation::KnownResult
-Relation::getImpliedResult(unsigned Op) const {
- if (Rel == Op) return KnownTrue;
- if (Op >= ICmpInst::FIRST_ICMP_PREDICATE &&
- Op <= ICmpInst::LAST_ICMP_PREDICATE) {
- if (Rel == unsigned(ICmpInst::getInversePredicate(ICmpInst::Predicate(Op))))
- return KnownFalse;
- } else if (Op <= FCmpInst::LAST_FCMP_PREDICATE) {
- if (Rel == unsigned(FCmpInst::getInversePredicate(FCmpInst::Predicate(Op))))
- return KnownFalse;
- }
-
- switch (Rel) {
- default: assert(0 && "Unknown prior value!");
- case ICmpInst::ICMP_EQ:
- if (Op == ICmpInst::ICMP_ULE || Op == ICmpInst::ICMP_SLE ||
- Op == ICmpInst::ICMP_UGE || Op == ICmpInst::ICMP_SGE) return KnownTrue;
- if (Op == ICmpInst::ICMP_ULT || Op == ICmpInst::ICMP_SLT ||
- Op == ICmpInst::ICMP_UGT || Op == ICmpInst::ICMP_SGT) return KnownFalse;
- break;
- case ICmpInst::ICMP_ULT:
- case ICmpInst::ICMP_SLT:
- if (Op == ICmpInst::ICMP_ULE || Op == ICmpInst::ICMP_SLE ||
- Op == ICmpInst::ICMP_NE) return KnownTrue;
- if (Op == ICmpInst::ICMP_EQ) return KnownFalse;
- break;
- case ICmpInst::ICMP_UGT:
- case ICmpInst::ICMP_SGT:
- if (Op == ICmpInst::ICMP_UGE || Op == ICmpInst::ICMP_SGE ||
- Op == ICmpInst::ICMP_NE) return KnownTrue;
- if (Op == ICmpInst::ICMP_EQ) return KnownFalse;
- break;
- case FCmpInst::FCMP_OEQ:
- if (Op == FCmpInst::FCMP_OLE || Op == FCmpInst::FCMP_OGE) return KnownTrue;
- if (Op == FCmpInst::FCMP_OLT || Op == FCmpInst::FCMP_OGT) return KnownFalse;
- break;
- case FCmpInst::FCMP_OLT:
- if (Op == FCmpInst::FCMP_ONE || Op == FCmpInst::FCMP_OLE) return KnownTrue;
- if (Op == FCmpInst::FCMP_OEQ) return KnownFalse;
- break;
- case FCmpInst::FCMP_OGT:
- if (Op == FCmpInst::FCMP_ONE || Op == FCmpInst::FCMP_OGE) return KnownTrue;
- if (Op == FCmpInst::FCMP_OEQ) return KnownFalse;
- break;
- case ICmpInst::ICMP_NE:
- case ICmpInst::ICMP_SLE:
- case ICmpInst::ICMP_ULE:
- case ICmpInst::ICMP_UGE:
- case ICmpInst::ICMP_SGE:
- case FCmpInst::FCMP_ONE:
- case FCmpInst::FCMP_OLE:
- case FCmpInst::FCMP_OGE:
- case FCmpInst::FCMP_FALSE:
- case FCmpInst::FCMP_ORD:
- case FCmpInst::FCMP_UNO:
- case FCmpInst::FCMP_UEQ:
- case FCmpInst::FCMP_UGT:
- case FCmpInst::FCMP_UGE:
- case FCmpInst::FCMP_ULT:
- case FCmpInst::FCMP_ULE:
- case FCmpInst::FCMP_UNE:
- case FCmpInst::FCMP_TRUE:
- break;
- }
- return Unknown;
-}
-
-
-//===----------------------------------------------------------------------===//
-// Printing Support...
-//===----------------------------------------------------------------------===//
-
-// print - Implement the standard print form to print out analysis information.
-void CEE::print(std::ostream &O, const Module *M) const {
- O << "\nPrinting Correlated Expression Info:\n";
- for (std::map<BasicBlock*, RegionInfo>::const_iterator I =
- RegionInfoMap.begin(), E = RegionInfoMap.end(); I != E; ++I)
- I->second.print(O);
-}
-
-// print - Output information about this region...
-void RegionInfo::print(std::ostream &OS) const {
- if (ValueMap.empty()) return;
-
- OS << " RegionInfo for basic block: " << BB->getName() << "\n";
- for (std::map<Value*, ValueInfo>::const_iterator
- I = ValueMap.begin(), E = ValueMap.end(); I != E; ++I)
- I->second.print(OS, I->first);
- OS << "\n";
-}
-
-// print - Output information about this value relation...
-void ValueInfo::print(std::ostream &OS, Value *V) const {
- if (Relationships.empty()) return;
-
- if (V) {
- OS << " ValueInfo for: ";
- WriteAsOperand(OS, V);
- }
- OS << "\n Bounds = " << Bounds << "\n";
- if (Replacement) {
- OS << " Replacement = ";
- WriteAsOperand(OS, Replacement);
- OS << "\n";
- }
- for (unsigned i = 0, e = Relationships.size(); i != e; ++i)
- Relationships[i].print(OS);
-}
-
-// print - Output this relation to the specified stream
-void Relation::print(std::ostream &OS) const {
- OS << " is ";
- switch (Rel) {
- default: OS << "*UNKNOWN*"; break;
- case ICmpInst::ICMP_EQ:
- case FCmpInst::FCMP_ORD:
- case FCmpInst::FCMP_UEQ:
- case FCmpInst::FCMP_OEQ: OS << "== "; break;
- case ICmpInst::ICMP_NE:
- case FCmpInst::FCMP_UNO:
- case FCmpInst::FCMP_UNE:
- case FCmpInst::FCMP_ONE: OS << "!= "; break;
- case ICmpInst::ICMP_ULT:
- case ICmpInst::ICMP_SLT:
- case FCmpInst::FCMP_ULT:
- case FCmpInst::FCMP_OLT: OS << "< "; break;
- case ICmpInst::ICMP_UGT:
- case ICmpInst::ICMP_SGT:
- case FCmpInst::FCMP_UGT:
- case FCmpInst::FCMP_OGT: OS << "> "; break;
- case ICmpInst::ICMP_ULE:
- case ICmpInst::ICMP_SLE:
- case FCmpInst::FCMP_ULE:
- case FCmpInst::FCMP_OLE: OS << "<= "; break;
- case ICmpInst::ICMP_UGE:
- case ICmpInst::ICMP_SGE:
- case FCmpInst::FCMP_UGE:
- case FCmpInst::FCMP_OGE: OS << ">= "; break;
- }
-
- WriteAsOperand(OS, Val);
- OS << "\n";
-}
-
-// Don't inline these methods or else we won't be able to call them from GDB!
-void Relation::dump() const { print(*cerr.stream()); }
-void ValueInfo::dump() const { print(*cerr.stream(), 0); }
-void RegionInfo::dump() const { print(*cerr.stream()); }
projects / oota-llvm.git / commitdiff