#include "llvm/IntrinsicInst.h"
#include "llvm/Type.h"
#include "llvm/DerivedTypes.h"
+#include "llvm/GlobalVariable.h"
#include "llvm/Support/CFG.h"
#include "llvm/Support/Debug.h"
+#include "llvm/Support/raw_ostream.h"
#include "llvm/Analysis/ConstantFolding.h"
#include "llvm/Transforms/Utils/BasicBlockUtils.h"
+#include "llvm/ADT/DenseMap.h"
#include "llvm/ADT/SmallVector.h"
#include "llvm/ADT/SmallPtrSet.h"
#include "llvm/ADT/Statistic.h"
STATISTIC(NumSpeculations, "Number of speculative executed instructions");
-#include "llvm/Support/CommandLine.h"
-static cl::opt<bool>
-DisableXForm("disable-xform", cl::Hidden, cl::init(false));
-
/// SafeToMergeTerminators - Return true if it is safe to merge these two
/// terminator instructions together.
///
PN->addIncoming(PN->getIncomingValueForBlock(ExistPred), NewPred);
}
-/// CanPropagatePredecessorsForPHIs - Return true if we can fold BB, an
-/// almost-empty BB ending in an unconditional branch to Succ, into succ.
-///
-/// Assumption: Succ is the single successor for BB.
-///
-static bool CanPropagatePredecessorsForPHIs(BasicBlock *BB, BasicBlock *Succ) {
- assert(*succ_begin(BB) == Succ && "Succ is not successor of BB!");
-
- DOUT << "Looking to fold " << BB->getNameStart() << " into "
- << Succ->getNameStart() << "\n";
- // Shortcut, if there is only a single predecessor is must be BB and merging
- // is always safe
- if (Succ->getSinglePredecessor()) return true;
-
- typedef SmallPtrSet<Instruction*, 16> InstrSet;
- InstrSet BBPHIs;
-
- // Make a list of all phi nodes in BB
- BasicBlock::iterator BBI = BB->begin();
- while (isa<PHINode>(*BBI)) BBPHIs.insert(BBI++);
-
- // Make a list of the predecessors of BB
- typedef SmallPtrSet<BasicBlock*, 16> BlockSet;
- BlockSet BBPreds(pred_begin(BB), pred_end(BB));
-
- // Use that list to make another list of common predecessors of BB and Succ
- BlockSet CommonPreds;
- for (pred_iterator PI = pred_begin(Succ), PE = pred_end(Succ);
- PI != PE; ++PI)
- if (BBPreds.count(*PI))
- CommonPreds.insert(*PI);
-
- // Shortcut, if there are no common predecessors, merging is always safe
- if (CommonPreds.empty())
- return true;
-
- // Look at all the phi nodes in Succ, to see if they present a conflict when
- // merging these blocks
- for (BasicBlock::iterator I = Succ->begin(); isa<PHINode>(I); ++I) {
- PHINode *PN = cast<PHINode>(I);
-
- // If the incoming value from BB is again a PHINode in
- // BB which has the same incoming value for *PI as PN does, we can
- // merge the phi nodes and then the blocks can still be merged
- PHINode *BBPN = dyn_cast<PHINode>(PN->getIncomingValueForBlock(BB));
- if (BBPN && BBPN->getParent() == BB) {
- for (BlockSet::iterator PI = CommonPreds.begin(), PE = CommonPreds.end();
- PI != PE; PI++) {
- if (BBPN->getIncomingValueForBlock(*PI)
- != PN->getIncomingValueForBlock(*PI)) {
- DOUT << "Can't fold, phi node " << *PN->getNameStart() << " in "
- << Succ->getNameStart() << " is conflicting with "
- << BBPN->getNameStart() << " with regard to common predecessor "
- << (*PI)->getNameStart() << "\n";
- return false;
- }
- }
- // Remove this phinode from the list of phis in BB, since it has been
- // handled.
- BBPHIs.erase(BBPN);
- } else {
- Value* Val = PN->getIncomingValueForBlock(BB);
- for (BlockSet::iterator PI = CommonPreds.begin(), PE = CommonPreds.end();
- PI != PE; PI++) {
- // See if the incoming value for the common predecessor is equal to the
- // one for BB, in which case this phi node will not prevent the merging
- // of the block.
- if (Val != PN->getIncomingValueForBlock(*PI)) {
- DOUT << "Can't fold, phi node " << *PN->getNameStart() << " in "
- << Succ->getNameStart() << " is conflicting with regard to common "
- << "predecessor " << (*PI)->getNameStart() << "\n";
- return false;
- }
- }
- }
- }
-
- // If there are any other phi nodes in BB that don't have a phi node in Succ
- // to merge with, they must be moved to Succ completely. However, for any
- // predecessors of Succ, branches will be added to the phi node that just
- // point to itself. So, for any common predecessors, this must not cause
- // conflicts.
- for (InstrSet::iterator I = BBPHIs.begin(), E = BBPHIs.end();
- I != E; I++) {
- PHINode *PN = cast<PHINode>(*I);
- for (BlockSet::iterator PI = CommonPreds.begin(), PE = CommonPreds.end();
- PI != PE; PI++)
- if (PN->getIncomingValueForBlock(*PI) != PN) {
- DOUT << "Can't fold, phi node " << *PN->getNameStart() << " in "
- << BB->getNameStart() << " is conflicting with regard to common "
- << "predecessor " << (*PI)->getNameStart() << "\n";
- return false;
- }
- }
-
- return true;
-}
-
-/// TryToSimplifyUncondBranchFromEmptyBlock - BB contains an unconditional
-/// branch to Succ, and contains no instructions other than PHI nodes and the
-/// branch. If possible, eliminate BB.
-static bool TryToSimplifyUncondBranchFromEmptyBlock(BasicBlock *BB,
- BasicBlock *Succ) {
- // Check to see if merging these blocks would cause conflicts for any of the
- // phi nodes in BB or Succ. If not, we can safely merge.
- if (!CanPropagatePredecessorsForPHIs(BB, Succ)) return false;
-
- DOUT << "Killing Trivial BB: \n" << *BB;
-
- if (isa<PHINode>(Succ->begin())) {
- // If there is more than one pred of succ, and there are PHI nodes in
- // the successor, then we need to add incoming edges for the PHI nodes
- //
- const SmallVector<BasicBlock*, 16> BBPreds(pred_begin(BB), pred_end(BB));
-
- // Loop over all of the PHI nodes in the successor of BB.
- for (BasicBlock::iterator I = Succ->begin(); isa<PHINode>(I); ++I) {
- PHINode *PN = cast<PHINode>(I);
- Value *OldVal = PN->removeIncomingValue(BB, false);
- assert(OldVal && "No entry in PHI for Pred BB!");
-
- // If this incoming value is one of the PHI nodes in BB, the new entries
- // in the PHI node are the entries from the old PHI.
- if (isa<PHINode>(OldVal) && cast<PHINode>(OldVal)->getParent() == BB) {
- PHINode *OldValPN = cast<PHINode>(OldVal);
- for (unsigned i = 0, e = OldValPN->getNumIncomingValues(); i != e; ++i)
- // Note that, since we are merging phi nodes and BB and Succ might
- // have common predecessors, we could end up with a phi node with
- // identical incoming branches. This will be cleaned up later (and
- // will trigger asserts if we try to clean it up now, without also
- // simplifying the corresponding conditional branch).
- PN->addIncoming(OldValPN->getIncomingValue(i),
- OldValPN->getIncomingBlock(i));
- } else {
- // Add an incoming value for each of the new incoming values.
- for (unsigned i = 0, e = BBPreds.size(); i != e; ++i)
- PN->addIncoming(OldVal, BBPreds[i]);
- }
- }
- }
-
- if (isa<PHINode>(&BB->front())) {
- SmallVector<BasicBlock*, 16>
- OldSuccPreds(pred_begin(Succ), pred_end(Succ));
-
- // Move all PHI nodes in BB to Succ if they are alive, otherwise
- // delete them.
- while (PHINode *PN = dyn_cast<PHINode>(&BB->front())) {
- if (PN->use_empty()) {
- // Just remove the dead phi. This happens if Succ's PHIs were the only
- // users of the PHI nodes.
- PN->eraseFromParent();
- continue;
- }
-
- // The instruction is alive, so this means that BB must dominate all
- // predecessors of Succ (Since all uses of the PN are after its
- // definition, so in Succ or a block dominated by Succ. If a predecessor
- // of Succ would not be dominated by BB, PN would violate the def before
- // use SSA demand). Therefore, we can simply move the phi node to the
- // next block.
- Succ->getInstList().splice(Succ->begin(),
- BB->getInstList(), BB->begin());
-
- // We need to add new entries for the PHI node to account for
- // predecessors of Succ that the PHI node does not take into
- // account. At this point, since we know that BB dominated succ and all
- // of its predecessors, this means that we should any newly added
- // incoming edges should use the PHI node itself as the value for these
- // edges, because they are loop back edges.
- for (unsigned i = 0, e = OldSuccPreds.size(); i != e; ++i)
- if (OldSuccPreds[i] != BB)
- PN->addIncoming(PN, OldSuccPreds[i]);
- }
- }
-
- // Everything that jumped to BB now goes to Succ.
- BB->replaceAllUsesWith(Succ);
- if (!Succ->hasName()) Succ->takeName(BB);
- BB->eraseFromParent(); // Delete the old basic block.
- return true;
-}
/// GetIfCondition - Given a basic block (BB) with two predecessors (and
/// presumably PHI nodes in it), check to see if the merge at this block is due
return 0;
}
-
/// DominatesMergePoint - If we have a merge point of an "if condition" as
/// accepted above, return true if the specified value dominates the block. We
/// don't handle the true generality of domination here, just a special case
// Okay, it looks like the instruction IS in the "condition". Check to
// see if its a cheap instruction to unconditionally compute, and if it
// only uses stuff defined outside of the condition. If so, hoist it out.
+ if (!I->isSafeToSpeculativelyExecute())
+ return false;
+
switch (I->getOpcode()) {
default: return false; // Cannot hoist this out safely.
- case Instruction::Load:
- // We can hoist loads that are non-volatile and obviously cannot trap.
- if (cast<LoadInst>(I)->isVolatile())
- return false;
- // FIXME: A computation of a constant can trap!
- if (!isa<AllocaInst>(I->getOperand(0)) &&
- !isa<Constant>(I->getOperand(0)))
- return false;
-
- // Finally, we have to check to make sure there are no instructions
- // before the load in its basic block, as we are going to hoist the loop
- // out to its predecessor.
- if (PBB->begin() != BasicBlock::iterator(I))
+ case Instruction::Load: {
+ // We have to check to make sure there are no instructions before the
+ // load in its basic block, as we are going to hoist the loop out to
+ // its predecessor.
+ BasicBlock::iterator IP = PBB->begin();
+ while (isa<DbgInfoIntrinsic>(IP))
+ IP++;
+ if (IP != BasicBlock::iterator(I))
return false;
break;
+ }
case Instruction::Add:
case Instruction::Sub:
case Instruction::And:
case Instruction::LShr:
case Instruction::AShr:
case Instruction::ICmp:
- case Instruction::FCmp:
- if (I->getOperand(0)->getType()->isFPOrFPVector())
- return false; // FP arithmetic might trap.
break; // These are all cheap and non-trapping instructions.
}
assert(ThisCases.size() == 1 && "Branch can only have one case!");
// Insert the new branch.
Instruction *NI = BranchInst::Create(ThisDef, TI);
+ (void) NI;
// Remove PHI node entries for the dead edge.
ThisCases[0].second->removePredecessor(TI->getParent());
- DOUT << "Threading pred instr: " << *Pred->getTerminator()
- << "Through successor TI: " << *TI << "Leaving: " << *NI << "\n";
+ DEBUG(errs() << "Threading pred instr: " << *Pred->getTerminator()
+ << "Through successor TI: " << *TI << "Leaving: " << *NI << "\n");
EraseTerminatorInstAndDCECond(TI);
return true;
for (unsigned i = 0, e = PredCases.size(); i != e; ++i)
DeadCases.insert(PredCases[i].first);
- DOUT << "Threading pred instr: " << *Pred->getTerminator()
- << "Through successor TI: " << *TI;
+ DEBUG(errs() << "Threading pred instr: " << *Pred->getTerminator()
+ << "Through successor TI: " << *TI);
for (unsigned i = SI->getNumCases()-1; i != 0; --i)
if (DeadCases.count(SI->getCaseValue(i))) {
SI->removeCase(i);
}
- DOUT << "Leaving: " << *TI << "\n";
+ DEBUG(errs() << "Leaving: " << *TI << "\n");
return true;
}
}
// Insert the new branch.
Instruction *NI = BranchInst::Create(TheRealDest, TI);
+ (void) NI;
- DOUT << "Threading pred instr: " << *Pred->getTerminator()
- << "Through successor TI: " << *TI << "Leaving: " << *NI << "\n";
+ DEBUG(errs() << "Threading pred instr: " << *Pred->getTerminator()
+ << "Through successor TI: " << *TI << "Leaving: " << *NI << "\n");
EraseTerminatorInstAndDCECond(TI);
return true;
return false;
}
+namespace {
+ /// ConstantIntOrdering - This class implements a stable ordering of constant
+ /// integers that does not depend on their address. This is important for
+ /// applications that sort ConstantInt's to ensure uniqueness.
+ struct ConstantIntOrdering {
+ bool operator()(const ConstantInt *LHS, const ConstantInt *RHS) const {
+ return LHS->getValue().ult(RHS->getValue());
+ }
+ };
+}
+
/// FoldValueComparisonIntoPredecessors - The specified terminator is a value
/// equality comparison instruction (either a switch or a branch on "X == c").
/// See if any of the predecessors of the terminator block are value comparisons
SmallVector<BasicBlock*, 16> Preds(pred_begin(BB), pred_end(BB));
while (!Preds.empty()) {
- BasicBlock *Pred = Preds.back();
- Preds.pop_back();
+ BasicBlock *Pred = Preds.pop_back_val();
// See if the predecessor is a comparison with the same value.
TerminatorInst *PTI = Pred->getTerminator();
if (PredDefault == BB) {
// If this is the default destination from PTI, only the edges in TI
// that don't occur in PTI, or that branch to BB will be activated.
- std::set<ConstantInt*> PTIHandled;
+ std::set<ConstantInt*, ConstantIntOrdering> PTIHandled;
for (unsigned i = 0, e = PredCases.size(); i != e; ++i)
if (PredCases[i].second != BB)
PTIHandled.insert(PredCases[i].first);
// If this is not the default destination from PSI, only the edges
// in SI that occur in PSI with a destination of BB will be
// activated.
- std::set<ConstantInt*> PTIHandled;
+ std::set<ConstantInt*, ConstantIntOrdering> PTIHandled;
for (unsigned i = 0, e = PredCases.size(); i != e; ++i)
if (PredCases[i].second == BB) {
PTIHandled.insert(PredCases[i].first);
// If there are any constants vectored to BB that TI doesn't handle,
// they must go to the default destination of TI.
- for (std::set<ConstantInt*>::iterator I = PTIHandled.begin(),
+ for (std::set<ConstantInt*, ConstantIntOrdering>::iterator I =
+ PTIHandled.begin(),
E = PTIHandled.end(); I != E; ++I) {
PredCases.push_back(std::make_pair(*I, BBDefault));
NewSuccessors.push_back(BBDefault);
if (InfLoopBlock == 0) {
// Insert it at the end of the function, because it's either code,
// or it won't matter if it's hot. :)
- InfLoopBlock = BasicBlock::Create("infloop", BB->getParent());
+ InfLoopBlock = BasicBlock::Create(BB->getContext(),
+ "infloop", BB->getParent());
BranchInst::Create(InfLoopBlock, InfLoopBlock);
}
NewSI->setSuccessor(i, InfLoopBlock);
return Changed;
}
+// isSafeToHoistInvoke - If we would need to insert a select that uses the
+// value of this invoke (comments in HoistThenElseCodeToIf explain why we
+// would need to do this), we can't hoist the invoke, as there is nowhere
+// to put the select in this case.
+static bool isSafeToHoistInvoke(BasicBlock *BB1, BasicBlock *BB2,
+ Instruction *I1, Instruction *I2) {
+ for (succ_iterator SI = succ_begin(BB1), E = succ_end(BB1); SI != E; ++SI) {
+ PHINode *PN;
+ for (BasicBlock::iterator BBI = SI->begin();
+ (PN = dyn_cast<PHINode>(BBI)); ++BBI) {
+ Value *BB1V = PN->getIncomingValueForBlock(BB1);
+ Value *BB2V = PN->getIncomingValueForBlock(BB2);
+ if (BB1V != BB2V && (BB1V==I1 || BB2V==I2)) {
+ return false;
+ }
+ }
+ }
+ return true;
+}
+
/// HoistThenElseCodeToIf - Given a conditional branch that goes to BB1 and
/// BB2, hoist any common code in the two blocks up into the branch block. The
/// caller of this function guarantees that BI's block dominates BB1 and BB2.
I1 = BB1_Itr++;
while (isa<DbgInfoIntrinsic>(I2))
I2 = BB2_Itr++;
- if (I1->getOpcode() != I2->getOpcode() || isa<PHINode>(I1) ||
- isa<InvokeInst>(I1) || !I1->isIdenticalTo(I2))
+ if (I1->getOpcode() != I2->getOpcode() || isa<PHINode>(I1) ||
+ !I1->isIdenticalToWhenDefined(I2) ||
+ (isa<InvokeInst>(I1) && !isSafeToHoistInvoke(BB1, BB2, I1, I2)))
return false;
// If we get here, we can hoist at least one instruction.
BIParent->getInstList().splice(BI, BB1->getInstList(), I1);
if (!I2->use_empty())
I2->replaceAllUsesWith(I1);
+ I1->intersectOptionalDataWith(I2);
BB2->getInstList().erase(I2);
I1 = BB1_Itr++;
I2 = BB2_Itr++;
while (isa<DbgInfoIntrinsic>(I2))
I2 = BB2_Itr++;
- } while (I1->getOpcode() == I2->getOpcode() && I1->isIdenticalTo(I2));
+ } while (I1->getOpcode() == I2->getOpcode() &&
+ I1->isIdenticalToWhenDefined(I2));
return true;
HoistTerminator:
+ // It may not be possible to hoist an invoke.
+ if (isa<InvokeInst>(I1) && !isSafeToHoistInvoke(BB1, BB2, I1, I2))
+ return true;
+
// Okay, it is safe to hoist the terminator.
Instruction *NT = I1->clone();
BIParent->getInstList().insert(BI, NT);
- if (NT->getType() != Type::VoidTy) {
+ if (NT->getType() != Type::getVoidTy(BB1->getContext())) {
I1->replaceAllUsesWith(NT);
I2->replaceAllUsesWith(NT);
NT->takeName(I1);
static bool SpeculativelyExecuteBB(BranchInst *BI, BasicBlock *BB1) {
// Only speculatively execution a single instruction (not counting the
// terminator) for now.
- BasicBlock::iterator BBI = BB1->begin();
- ++BBI; // must have at least a terminator
- if (BBI == BB1->end()) return false; // only one inst
- ++BBI;
- if (BBI != BB1->end()) return false; // more than 2 insts.
+ Instruction *HInst = NULL;
+ Instruction *Term = BB1->getTerminator();
+ for (BasicBlock::iterator BBI = BB1->begin(), BBE = BB1->end();
+ BBI != BBE; ++BBI) {
+ Instruction *I = BBI;
+ // Skip debug info.
+ if (isa<DbgInfoIntrinsic>(I)) continue;
+ if (I == Term) break;
+
+ if (!HInst)
+ HInst = I;
+ else
+ return false;
+ }
+ if (!HInst)
+ return false;
// Be conservative for now. FP select instruction can often be expensive.
Value *BrCond = BI->getCondition();
// %t1 = icmp
// %t4 = add %t2, c
// %t3 = select i1 %t1, %t2, %t3
- Instruction *I = BB1->begin();
- switch (I->getOpcode()) {
+ switch (HInst->getOpcode()) {
default: return false; // Not safe / profitable to hoist.
case Instruction::Add:
case Instruction::Sub:
- // FP arithmetic might trap. Not worth doing for vector ops.
- if (I->getType()->isFloatingPoint() || isa<VectorType>(I->getType()))
+ // Not worth doing for vector ops.
+ if (isa<VectorType>(HInst->getType()))
return false;
break;
case Instruction::And:
case Instruction::LShr:
case Instruction::AShr:
// Don't mess with vector operations.
- if (isa<VectorType>(I->getType()))
+ if (isa<VectorType>(HInst->getType()))
return false;
break; // These are all cheap and non-trapping instructions.
}
// If the instruction is obviously dead, don't try to predicate it.
- if (I->use_empty()) {
- I->eraseFromParent();
+ if (HInst->use_empty()) {
+ HInst->eraseFromParent();
return true;
}
Value *FalseV = NULL;
BasicBlock *BB2 = BB1->getTerminator()->getSuccessor(0);
- for (Value::use_iterator UI = I->use_begin(), E = I->use_end();
+ for (Value::use_iterator UI = HInst->use_begin(), E = HInst->use_end();
UI != E; ++UI) {
// Ignore any user that is not a PHI node in BB2. These can only occur in
// unreachable blocks, because they would not be dominated by the instr.
// Do not hoist the instruction if any of its operands are defined but not
// used in this BB. The transformation will prevent the operand from
// being sunk into the use block.
- for (User::op_iterator i = I->op_begin(), e = I->op_end(); i != e; ++i) {
+ for (User::op_iterator i = HInst->op_begin(), e = HInst->op_end();
+ i != e; ++i) {
Instruction *OpI = dyn_cast<Instruction>(*i);
if (OpI && OpI->getParent() == BIParent &&
!OpI->isUsedInBasicBlock(BIParent))
}
// If we get here, we can hoist the instruction. Try to place it
- // before the icmp instruction preceeding the conditional branch.
+ // before the icmp instruction preceding the conditional branch.
BasicBlock::iterator InsertPos = BI;
- if (InsertPos != BIParent->begin())
+ if (InsertPos != BIParent->begin())
+ --InsertPos;
+ // Skip debug info between condition and branch.
+ while (InsertPos != BIParent->begin() && isa<DbgInfoIntrinsic>(InsertPos))
--InsertPos;
if (InsertPos == BrCond && !isa<PHINode>(BrCond)) {
SmallPtrSet<Instruction *, 4> BB1Insns;
}
} else
InsertPos = BI;
- BIParent->getInstList().splice(InsertPos, BB1->getInstList(), I);
+ BIParent->getInstList().splice(InsertPos, BB1->getInstList(), HInst);
// Create a select whose true value is the speculatively executed value and
// false value is the previously determined FalseV.
SelectInst *SI;
if (Invert)
- SI = SelectInst::Create(BrCond, FalseV, I,
- FalseV->getName() + "." + I->getName(), BI);
+ SI = SelectInst::Create(BrCond, FalseV, HInst,
+ FalseV->getName() + "." + HInst->getName(), BI);
else
- SI = SelectInst::Create(BrCond, I, FalseV,
- I->getName() + "." + FalseV->getName(), BI);
+ SI = SelectInst::Create(BrCond, HInst, FalseV,
+ HInst->getName() + "." + FalseV->getName(), BI);
// Make the PHI node use the select for all incoming values for "then" and
// "if" blocks.
BranchInst *BI = cast<BranchInst>(BB->getTerminator());
unsigned Size = 0;
- // If this basic block contains anything other than a PHI (which controls the
- // branch) and branch itself, bail out. FIXME: improve this in the future.
- for (BasicBlock::iterator BBI = BB->begin(); &*BBI != BI; ++BBI, ++Size) {
+ for (BasicBlock::iterator BBI = BB->begin(); &*BBI != BI; ++BBI) {
+ if (isa<DbgInfoIntrinsic>(BBI))
+ continue;
if (Size > 10) return false; // Don't clone large BB's.
+ ++Size;
- // We can only support instructions that are do not define values that are
+ // We can only support instructions that do not define values that are
// live outside of the current basic block.
for (Value::use_iterator UI = BBI->use_begin(), E = BBI->use_end();
UI != E; ++UI) {
for (unsigned i = 0, e = PN->getNumIncomingValues(); i != e; ++i) {
ConstantInt *CB;
if ((CB = dyn_cast<ConstantInt>(PN->getIncomingValue(i))) &&
- CB->getType() == Type::Int1Ty) {
+ CB->getType() == Type::getInt1Ty(BB->getContext())) {
// Okay, we now know that all edges from PredBB should be revectored to
// branch to RealDest.
BasicBlock *PredBB = PN->getIncomingBlock(i);
// difficult cases. Instead of being smart about this, just insert a new
// block that jumps to the destination block, effectively splitting
// the edge we are about to create.
- BasicBlock *EdgeBB = BasicBlock::Create(RealDest->getName()+".critedge",
+ BasicBlock *EdgeBB = BasicBlock::Create(BB->getContext(),
+ RealDest->getName()+".critedge",
RealDest->getParent(), RealDest);
BranchInst::Create(RealDest, EdgeBB);
PHINode *PN;
if (NumPhis > 2)
return false;
- DOUT << "FOUND IF CONDITION! " << *IfCond << " T: "
- << IfTrue->getName() << " F: " << IfFalse->getName() << "\n";
+ DEBUG(errs() << "FOUND IF CONDITION! " << *IfCond << " T: "
+ << IfTrue->getName() << " F: " << IfFalse->getName() << "\n");
// Loop over the PHI's seeing if we can promote them all to select
// instructions. While we are at it, keep track of the instructions
if (FalseRet->getNumOperands() == 0) {
TrueSucc->removePredecessor(BI->getParent());
FalseSucc->removePredecessor(BI->getParent());
- ReturnInst::Create(0, BI);
+ ReturnInst::Create(BI->getContext(), 0, BI);
EraseTerminatorInstAndDCECond(BI);
return true;
}
}
Value *RI = !TrueValue ?
- ReturnInst::Create(BI) :
- ReturnInst::Create(TrueValue, BI);
+ ReturnInst::Create(BI->getContext(), BI) :
+ ReturnInst::Create(BI->getContext(), TrueValue, BI);
+ (void) RI;
- DOUT << "\nCHANGING BRANCH TO TWO RETURNS INTO SELECT:"
- << "\n " << *BI << "NewRet = " << *RI
- << "TRUEBLOCK: " << *TrueSucc << "FALSEBLOCK: "<< *FalseSucc;
+ DEBUG(errs() << "\nCHANGING BRANCH TO TWO RETURNS INTO SELECT:"
+ << "\n " << *BI << "NewRet = " << *RI
+ << "TRUEBLOCK: " << *TrueSucc << "FALSEBLOCK: "<< *FalseSucc);
EraseTerminatorInstAndDCECond(BI);
/// and if a predecessor branches to us and one of our successors, fold the
/// setcc into the predecessor and use logical operations to pick the right
/// destination.
-static bool FoldBranchToCommonDest(BranchInst *BI) {
+bool llvm::FoldBranchToCommonDest(BranchInst *BI) {
BasicBlock *BB = BI->getParent();
Instruction *Cond = dyn_cast<Instruction>(BI->getCondition());
if (Cond == 0) return false;
else
continue;
- DOUT << "FOLDING BRANCH TO COMMON DEST:\n" << *PBI << *BB;
+ DEBUG(errs() << "FOLDING BRANCH TO COMMON DEST:\n" << *PBI << *BB);
// If we need to invert the condition in the pred block to match, do so now.
if (InvertPredCond) {
static bool SimplifyCondBranchToCondBranch(BranchInst *PBI, BranchInst *BI) {
assert(PBI->isConditional() && BI->isConditional());
BasicBlock *BB = BI->getParent();
-
+
// If this block ends with a branch instruction, and if there is a
// predecessor that ends on a branch of the same condition, make
// this conditional branch redundant.
if (BB->getSinglePredecessor()) {
// Turn this into a branch on constant.
bool CondIsTrue = PBI->getSuccessor(0) == BB;
- BI->setCondition(ConstantInt::get(Type::Int1Ty, CondIsTrue));
+ BI->setCondition(ConstantInt::get(Type::getInt1Ty(BB->getContext()),
+ CondIsTrue));
return true; // Nuke the branch on constant.
}
// in the constant and simplify the block result. Subsequent passes of
// simplifycfg will thread the block.
if (BlockIsSimpleEnoughToThreadThrough(BB)) {
- PHINode *NewPN = PHINode::Create(Type::Int1Ty,
+ PHINode *NewPN = PHINode::Create(Type::getInt1Ty(BB->getContext()),
BI->getCondition()->getName() + ".pr",
BB->begin());
// Okay, we're going to insert the PHI node. Since PBI is not the only
PBI->getCondition() == BI->getCondition() &&
PBI->getSuccessor(0) != PBI->getSuccessor(1)) {
bool CondIsTrue = PBI->getSuccessor(0) == BB;
- NewPN->addIncoming(ConstantInt::get(Type::Int1Ty,
+ NewPN->addIncoming(ConstantInt::get(Type::getInt1Ty(BB->getContext()),
CondIsTrue), *PI);
} else {
NewPN->addIncoming(BI->getCondition(), *PI);
// Finally, if everything is ok, fold the branches to logical ops.
BasicBlock *OtherDest = BI->getSuccessor(BIOp ^ 1);
- DOUT << "FOLDING BRs:" << *PBI->getParent()
- << "AND: " << *BI->getParent();
+ DEBUG(errs() << "FOLDING BRs:" << *PBI->getParent()
+ << "AND: " << *BI->getParent());
// If OtherDest *is* BB, then BB is a basic block with a single conditional
if (OtherDest == BB) {
// Insert it at the end of the function, because it's either code,
// or it won't matter if it's hot. :)
- BasicBlock *InfLoopBlock = BasicBlock::Create("infloop", BB->getParent());
+ BasicBlock *InfLoopBlock = BasicBlock::Create(BB->getContext(),
+ "infloop", BB->getParent());
BranchInst::Create(InfLoopBlock, InfLoopBlock);
OtherDest = InfLoopBlock;
}
- DOUT << *PBI->getParent()->getParent();
+ DEBUG(errs() << *PBI->getParent()->getParent());
// BI may have other predecessors. Because of this, we leave
// it alone, but modify PBI.
}
}
- DOUT << "INTO: " << *PBI->getParent();
-
- DOUT << *PBI->getParent()->getParent();
+ DEBUG(errs() << "INTO: " << *PBI->getParent());
+ DEBUG(errs() << *PBI->getParent()->getParent());
// This basic block is probably dead. We know it has at least
// one fewer predecessor.
return true;
}
-
-namespace {
- /// ConstantIntOrdering - This class implements a stable ordering of constant
- /// integers that does not depend on their address. This is important for
- /// applications that sort ConstantInt's to ensure uniqueness.
- struct ConstantIntOrdering {
- bool operator()(const ConstantInt *LHS, const ConstantInt *RHS) const {
- return LHS->getValue().ult(RHS->getValue());
- }
- };
-}
-
/// SimplifyCFG - This function is used to do simplification of a CFG. For
/// example, it adjusts branches to branches to eliminate the extra hop, it
/// eliminates unreachable basic blocks, and does other "peephole" optimization
// Remove basic blocks that have no predecessors... or that just have themself
// as a predecessor. These are unreachable.
if (pred_begin(BB) == pred_end(BB) || BB->getSinglePredecessor() == BB) {
- DOUT << "Removing BB: \n" << *BB;
+ DEBUG(errs() << "Removing BB: \n" << *BB);
DeleteDeadBlock(BB);
return true;
}
// away...
Changed |= ConstantFoldTerminator(BB);
+ // Check for and eliminate duplicate PHI nodes in this block.
+ Changed |= EliminateDuplicatePHINodes(BB);
+
// If there is a trivial two-entry PHI node in this basic block, and we can
// eliminate it, do so now.
if (PHINode *PN = dyn_cast<PHINode>(BB->begin()))
}
// If we found some, do the transformation!
- if (!UncondBranchPreds.empty() && !DisableXForm) {
+ if (!UncondBranchPreds.empty()) {
while (!UncondBranchPreds.empty()) {
- BasicBlock *Pred = UncondBranchPreds.back();
- DOUT << "FOLDING: " << *BB
- << "INTO UNCOND BRANCH PRED: " << *Pred;
- UncondBranchPreds.pop_back();
+ BasicBlock *Pred = UncondBranchPreds.pop_back_val();
+ DEBUG(errs() << "FOLDING: " << *BB
+ << "INTO UNCOND BRANCH PRED: " << *Pred);
Instruction *UncondBranch = Pred->getTerminator();
// Clone the return and add it to the end of the predecessor.
Instruction *NewRet = RI->clone();
// instruction. If any of them just select between returns, change the
// branch itself into a select/return pair.
while (!CondBranchPreds.empty()) {
- BranchInst *BI = CondBranchPreds.back();
- CondBranchPreds.pop_back();
+ BranchInst *BI = CondBranchPreds.pop_back_val();
// Check to see if the non-BB successor is also a return block.
if (isa<ReturnInst>(BI->getSuccessor(0)->getTerminator()) &&
} else if (isa<UnwindInst>(BB->begin())) {
// Check to see if the first instruction in this block is just an unwind.
// If so, replace any invoke instructions which use this as an exception
- // destination with call instructions, and any unconditional branch
- // predecessor with an unwind.
+ // destination with call instructions.
//
SmallVector<BasicBlock*, 8> Preds(pred_begin(BB), pred_end(BB));
while (!Preds.empty()) {
BasicBlock *Pred = Preds.back();
- if (BranchInst *BI = dyn_cast<BranchInst>(Pred->getTerminator())) {
- if (BI->isUnconditional()) {
- Pred->getInstList().pop_back(); // nuke uncond branch
- new UnwindInst(Pred); // Use unwind.
- Changed = true;
- }
- } else if (InvokeInst *II = dyn_cast<InvokeInst>(Pred->getTerminator()))
+ if (InvokeInst *II = dyn_cast<InvokeInst>(Pred->getTerminator()))
if (II->getUnwindDest() == BB) {
// Insert a new branch instruction before the invoke, because this
- // is now a fall through...
+ // is now a fall through.
BranchInst *BI = BranchInst::Create(II->getNormalDest(), II);
Pred->getInstList().remove(II); // Take out of symbol table
- // Insert the call now...
+ // Insert the call now.
SmallVector<Value*,8> Args(II->op_begin()+3, II->op_end());
CallInst *CI = CallInst::Create(II->getCalledValue(),
Args.begin(), Args.end(),
II->getName(), BI);
CI->setCallingConv(II->getCallingConv());
CI->setAttributes(II->getAttributes());
- // If the invoke produced a value, the Call now does instead
+ // If the invoke produced a value, the Call now does instead.
II->replaceAllUsesWith(CI);
delete II;
Changed = true;
if (BI->isUnconditional()) {
BasicBlock::iterator BBI = BB->getFirstNonPHI();
- BasicBlock *Succ = BI->getSuccessor(0);
// Ignore dbg intrinsics.
while (isa<DbgInfoIntrinsic>(BBI))
++BBI;
- if (BBI->isTerminator() && // Terminator is the only non-phi instruction!
- Succ != BB) // Don't hurt infinite loops!
- if (TryToSimplifyUncondBranchFromEmptyBlock(BB, Succ))
+ if (BBI->isTerminator()) // Terminator is the only non-phi instruction!
+ if (TryToSimplifyUncondBranchFromEmptyBlock(BB))
return true;
} else { // Conditional branch
--BBI;
// Do not delete instructions that can have side effects, like calls
// (which may never return) and volatile loads and stores.
- if (isa<CallInst>(BBI)) break;
+ if (isa<CallInst>(BBI) && !isa<DbgInfoIntrinsic>(BBI)) break;
if (StoreInst *SI = dyn_cast<StoreInst>(BBI))
if (SI->isVolatile())
if (BranchInst *BI = dyn_cast<BranchInst>(TI)) {
if (BI->isUnconditional()) {
if (BI->getSuccessor(0) == BB) {
- new UnreachableInst(TI);
+ new UnreachableInst(TI->getContext(), TI);
TI->eraseFromParent();
Changed = true;
}
projects / oota-llvm.git / blobdiff