[llvm-commits] [llvm] r162867 - /llvm/trunk/lib/Transforms/Utils/SimplifyCFG.cpp
Andrew Trick
atrick at apple.com
Wed Aug 29 14:46:36 PDT 2012
Author: atrick
Date: Wed Aug 29 16:46:36 2012
New Revision: 162867
URL: http://llvm.org/viewvc/llvm-project?rev=162867&view=rev
Log:
whitespace
Modified:
llvm/trunk/lib/Transforms/Utils/SimplifyCFG.cpp
Modified: llvm/trunk/lib/Transforms/Utils/SimplifyCFG.cpp
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/Transforms/Utils/SimplifyCFG.cpp?rev=162867&r1=162866&r2=162867&view=diff
==============================================================================
--- llvm/trunk/lib/Transforms/Utils/SimplifyCFG.cpp (original)
+++ llvm/trunk/lib/Transforms/Utils/SimplifyCFG.cpp Wed Aug 29 16:46:36 2012
@@ -101,14 +101,14 @@
///
static bool SafeToMergeTerminators(TerminatorInst *SI1, TerminatorInst *SI2) {
if (SI1 == SI2) return false; // Can't merge with self!
-
+
// It is not safe to merge these two switch instructions if they have a common
// successor, and if that successor has a PHI node, and if *that* PHI node has
// conflicting incoming values from the two switch blocks.
BasicBlock *SI1BB = SI1->getParent();
BasicBlock *SI2BB = SI2->getParent();
SmallPtrSet<BasicBlock*, 16> SI1Succs(succ_begin(SI1BB), succ_end(SI1BB));
-
+
for (succ_iterator I = succ_begin(SI2BB), E = succ_end(SI2BB); I != E; ++I)
if (SI1Succs.count(*I))
for (BasicBlock::iterator BBI = (*I)->begin();
@@ -118,7 +118,7 @@
PN->getIncomingValueForBlock(SI2BB))
return false;
}
-
+
return true;
}
@@ -135,7 +135,7 @@
assert(SI1->isUnconditional() && SI2->isConditional());
// We fold the unconditional branch if we can easily update all PHI nodes in
- // common successors:
+ // common successors:
// 1> We have a constant incoming value for the conditional branch;
// 2> We have "Cond" as the incoming value for the unconditional branch;
// 3> SI2->getCondition() and Cond have same operands.
@@ -170,7 +170,7 @@
static void AddPredecessorToBlock(BasicBlock *Succ, BasicBlock *NewPred,
BasicBlock *ExistPred) {
if (!isa<PHINode>(Succ->begin())) return; // Quick exit if nothing to do
-
+
PHINode *PN;
for (BasicBlock::iterator I = Succ->begin();
(PN = dyn_cast<PHINode>(I)); ++I)
@@ -222,7 +222,7 @@
// doesn't dominate BB.
if (Pred2->getSinglePredecessor() == 0)
return 0;
-
+
// If we found a conditional branch predecessor, make sure that it branches
// to BB and Pred2Br. If it doesn't, this isn't an "if statement".
if (Pred1Br->getSuccessor(0) == BB &&
@@ -252,7 +252,7 @@
// Otherwise, if this is a conditional branch, then we can use it!
BranchInst *BI = dyn_cast<BranchInst>(CommonPred->getTerminator());
if (BI == 0) return 0;
-
+
assert(BI->isConditional() && "Two successors but not conditional?");
if (BI->getSuccessor(0) == Pred1) {
IfTrue = Pred1;
@@ -345,7 +345,7 @@
// If we aren't allowing aggressive promotion anymore, then don't consider
// instructions in the 'if region'.
if (AggressiveInsts == 0) return false;
-
+
// If we have seen this instruction before, don't count it again.
if (AggressiveInsts->count(I)) return true;
@@ -411,7 +411,7 @@
const TargetData *TD, bool isEQ, unsigned &UsedICmps) {
Instruction *I = dyn_cast<Instruction>(V);
if (I == 0) return 0;
-
+
// If this is an icmp against a constant, handle this as one of the cases.
if (ICmpInst *ICI = dyn_cast<ICmpInst>(I)) {
if (ConstantInt *C = GetConstantInt(I->getOperand(1), TD)) {
@@ -420,21 +420,21 @@
Vals.push_back(C);
return I->getOperand(0);
}
-
+
// If we have "x ult 3" comparison, for example, then we can add 0,1,2 to
// the set.
ConstantRange Span =
ConstantRange::makeICmpRegion(ICI->getPredicate(), C->getValue());
-
+
// If this is an and/!= check then we want to optimize "x ugt 2" into
// x != 0 && x != 1.
if (!isEQ)
Span = Span.inverse();
-
+
// If there are a ton of values, we don't want to make a ginormous switch.
if (Span.getSetSize().ugt(8) || Span.isEmptySet())
return 0;
-
+
for (APInt Tmp = Span.getLower(); Tmp != Span.getUpper(); ++Tmp)
Vals.push_back(ConstantInt::get(V->getContext(), Tmp));
UsedICmps++;
@@ -442,11 +442,11 @@
}
return 0;
}
-
+
// Otherwise, we can only handle an | or &, depending on isEQ.
if (I->getOpcode() != (isEQ ? Instruction::Or : Instruction::And))
return 0;
-
+
unsigned NumValsBeforeLHS = Vals.size();
unsigned UsedICmpsBeforeLHS = UsedICmps;
if (Value *LHS = GatherConstantCompares(I->getOperand(0), Vals, Extra, TD,
@@ -467,12 +467,12 @@
Extra = I->getOperand(1);
return LHS;
}
-
+
Vals.resize(NumValsBeforeLHS);
UsedICmps = UsedICmpsBeforeLHS;
return 0;
}
-
+
// If the LHS can't be folded in, but Extra is available and RHS can, try to
// use LHS as Extra.
if (Extra == 0 || Extra == I->getOperand(0)) {
@@ -484,7 +484,7 @@
assert(Vals.size() == NumValsBeforeLHS);
Extra = OldExtra;
}
-
+
return 0;
}
@@ -634,7 +634,7 @@
// can simplify TI.
if (!ValuesOverlap(PredCases, ThisCases))
return false;
-
+
if (isa<BranchInst>(TI)) {
// Okay, one of the successors of this condbr is dead. Convert it to a
// uncond br.
@@ -652,7 +652,7 @@
EraseTerminatorInstAndDCECond(TI);
return true;
}
-
+
SwitchInst *SI = cast<SwitchInst>(TI);
// Okay, TI has cases that are statically dead, prune them away.
SmallPtrSet<Constant*, 16> DeadCases;
@@ -673,7 +673,7 @@
DEBUG(dbgs() << "Leaving: " << *TI << "\n");
return true;
}
-
+
// Otherwise, TI's block must correspond to some matched value. Find out
// which value (or set of values) this is.
ConstantInt *TIV = 0;
@@ -822,7 +822,7 @@
// 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*, ConstantIntOrdering>::iterator I =
+ for (std::set<ConstantInt*, ConstantIntOrdering>::iterator I =
PTIHandled.begin(),
E = PTIHandled.end(); I != E; ++I) {
PredCases.push_back(ValueEqualityComparisonCase(*I, BBDefault));
@@ -984,11 +984,11 @@
Value *BB1V = PN->getIncomingValueForBlock(BB1);
Value *BB2V = PN->getIncomingValueForBlock(BB2);
if (BB1V == BB2V) continue;
-
+
// These values do not agree. Insert a select instruction before NT
// that determines the right value.
SelectInst *&SI = InsertedSelects[std::make_pair(BB1V, BB2V)];
- if (SI == 0)
+ if (SI == 0)
SI = cast<SelectInst>
(Builder.CreateSelect(BI->getCondition(), BB1V, BB2V,
BB1V->getName()+"."+BB2V->getName()));
@@ -1056,7 +1056,7 @@
// 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 = HInst->op_begin(), e = HInst->op_end();
+ 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 &&
@@ -1112,7 +1112,7 @@
// as well.
if (PHIs.empty())
return false;
-
+
// If we get here, we can hoist the instruction and if-convert.
DEBUG(dbgs() << "SPECULATIVELY EXECUTING BB" << *BB1 << "\n";);
@@ -1162,13 +1162,13 @@
static bool BlockIsSimpleEnoughToThreadThrough(BasicBlock *BB) {
BranchInst *BI = cast<BranchInst>(BB->getTerminator());
unsigned Size = 0;
-
+
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 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();
@@ -1176,7 +1176,7 @@
Instruction *U = cast<Instruction>(*UI);
if (U->getParent() != BB || isa<PHINode>(U)) return false;
}
-
+
// Looks ok, continue checking.
}
@@ -1194,31 +1194,31 @@
// outside of the block.
if (!PN || PN->getParent() != BB || !PN->hasOneUse())
return false;
-
+
// Degenerate case of a single entry PHI.
if (PN->getNumIncomingValues() == 1) {
FoldSingleEntryPHINodes(PN->getParent());
- return true;
+ return true;
}
// Now we know that this block has multiple preds and two succs.
if (!BlockIsSimpleEnoughToThreadThrough(BB)) return false;
-
+
// Okay, this is a simple enough basic block. See if any phi values are
// constants.
for (unsigned i = 0, e = PN->getNumIncomingValues(); i != e; ++i) {
ConstantInt *CB = dyn_cast<ConstantInt>(PN->getIncomingValue(i));
if (CB == 0 || !CB->getType()->isIntegerTy(1)) continue;
-
+
// Okay, we now know that all edges from PredBB should be revectored to
// branch to RealDest.
BasicBlock *PredBB = PN->getIncomingBlock(i);
BasicBlock *RealDest = BI->getSuccessor(!CB->getZExtValue());
-
+
if (RealDest == BB) continue; // Skip self loops.
// Skip if the predecessor's terminator is an indirect branch.
if (isa<IndirectBrInst>(PredBB->getTerminator())) continue;
-
+
// The dest block might have PHI nodes, other predecessors and other
// difficult cases. Instead of being smart about this, just insert a new
// block that jumps to the destination block, effectively splitting
@@ -1227,7 +1227,7 @@
RealDest->getName()+".critedge",
RealDest->getParent(), RealDest);
BranchInst::Create(RealDest, EdgeBB);
-
+
// Update PHI nodes.
AddPredecessorToBlock(RealDest, EdgeBB, BB);
@@ -1244,7 +1244,7 @@
// Clone the instruction.
Instruction *N = BBI->clone();
if (BBI->hasName()) N->setName(BBI->getName()+".c");
-
+
// Update operands due to translation.
for (User::op_iterator i = N->op_begin(), e = N->op_end();
i != e; ++i) {
@@ -1252,7 +1252,7 @@
if (PI != TranslateMap.end())
*i = PI->second;
}
-
+
// Check for trivial simplification.
if (Value *V = SimplifyInstruction(N, TD)) {
TranslateMap[BBI] = V;
@@ -1297,7 +1297,7 @@
// Don't bother if the branch will be constant folded trivially.
isa<ConstantInt>(IfCond))
return false;
-
+
// Okay, we found that we can merge this two-entry phi node into a select.
// Doing so would require us to fold *all* two entry phi nodes in this block.
// At some point this becomes non-profitable (particularly if the target
@@ -1307,14 +1307,14 @@
for (BasicBlock::iterator I = BB->begin(); isa<PHINode>(I); ++NumPhis, ++I)
if (NumPhis > 2)
return false;
-
+
// 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
// that need to be moved to the dominating block.
SmallPtrSet<Instruction*, 4> AggressiveInsts;
unsigned MaxCostVal0 = PHINodeFoldingThreshold,
MaxCostVal1 = PHINodeFoldingThreshold;
-
+
for (BasicBlock::iterator II = BB->begin(); isa<PHINode>(II);) {
PHINode *PN = cast<PHINode>(II++);
if (Value *V = SimplifyInstruction(PN, TD)) {
@@ -1322,19 +1322,19 @@
PN->eraseFromParent();
continue;
}
-
+
if (!DominatesMergePoint(PN->getIncomingValue(0), BB, &AggressiveInsts,
MaxCostVal0) ||
!DominatesMergePoint(PN->getIncomingValue(1), BB, &AggressiveInsts,
MaxCostVal1))
return false;
}
-
+
// If we folded the first phi, PN dangles at this point. Refresh it. If
// we ran out of PHIs then we simplified them all.
PN = dyn_cast<PHINode>(BB->begin());
if (PN == 0) return true;
-
+
// Don't fold i1 branches on PHIs which contain binary operators. These can
// often be turned into switches and other things.
if (PN->getType()->isIntegerTy(1) &&
@@ -1342,7 +1342,7 @@
isa<BinaryOperator>(PN->getIncomingValue(1)) ||
isa<BinaryOperator>(IfCond)))
return false;
-
+
// If we all PHI nodes are promotable, check to make sure that all
// instructions in the predecessor blocks can be promoted as well. If
// not, we won't be able to get rid of the control flow, so it's not
@@ -1362,7 +1362,7 @@
return false;
}
}
-
+
if (cast<BranchInst>(IfBlock2->getTerminator())->isConditional()) {
IfBlock2 = 0;
} else {
@@ -1375,15 +1375,15 @@
return false;
}
}
-
+
DEBUG(dbgs() << "FOUND IF CONDITION! " << *IfCond << " T: "
<< IfTrue->getName() << " F: " << IfFalse->getName() << "\n");
-
+
// If we can still promote the PHI nodes after this gauntlet of tests,
// do all of the PHI's now.
Instruction *InsertPt = DomBlock->getTerminator();
IRBuilder<true, NoFolder> Builder(InsertPt);
-
+
// Move all 'aggressive' instructions, which are defined in the
// conditional parts of the if's up to the dominating block.
if (IfBlock1)
@@ -1394,19 +1394,19 @@
DomBlock->getInstList().splice(InsertPt,
IfBlock2->getInstList(), IfBlock2->begin(),
IfBlock2->getTerminator());
-
+
while (PHINode *PN = dyn_cast<PHINode>(BB->begin())) {
// Change the PHI node into a select instruction.
Value *TrueVal = PN->getIncomingValue(PN->getIncomingBlock(0) == IfFalse);
Value *FalseVal = PN->getIncomingValue(PN->getIncomingBlock(0) == IfTrue);
-
- SelectInst *NV =
+
+ SelectInst *NV =
cast<SelectInst>(Builder.CreateSelect(IfCond, TrueVal, FalseVal, ""));
PN->replaceAllUsesWith(NV);
NV->takeName(PN);
PN->eraseFromParent();
}
-
+
// At this point, IfBlock1 and IfBlock2 are both empty, so our if statement
// has been flattened. Change DomBlock to jump directly to our new block to
// avoid other simplifycfg's kicking in on the diamond.
@@ -1420,14 +1420,14 @@
/// SimplifyCondBranchToTwoReturns - If we found a conditional branch that goes
/// to two returning blocks, try to merge them together into one return,
/// introducing a select if the return values disagree.
-static bool SimplifyCondBranchToTwoReturns(BranchInst *BI,
+static bool SimplifyCondBranchToTwoReturns(BranchInst *BI,
IRBuilder<> &Builder) {
assert(BI->isConditional() && "Must be a conditional branch");
BasicBlock *TrueSucc = BI->getSuccessor(0);
BasicBlock *FalseSucc = BI->getSuccessor(1);
ReturnInst *TrueRet = cast<ReturnInst>(TrueSucc->getTerminator());
ReturnInst *FalseRet = cast<ReturnInst>(FalseSucc->getTerminator());
-
+
// Check to ensure both blocks are empty (just a return) or optionally empty
// with PHI nodes. If there are other instructions, merging would cause extra
// computation on one path or the other.
@@ -1447,12 +1447,12 @@
EraseTerminatorInstAndDCECond(BI);
return true;
}
-
+
// Otherwise, figure out what the true and false return values are
// so we can insert a new select instruction.
Value *TrueValue = TrueRet->getReturnValue();
Value *FalseValue = FalseRet->getReturnValue();
-
+
// Unwrap any PHI nodes in the return blocks.
if (PHINode *TVPN = dyn_cast_or_null<PHINode>(TrueValue))
if (TVPN->getParent() == TrueSucc)
@@ -1460,7 +1460,7 @@
if (PHINode *FVPN = dyn_cast_or_null<PHINode>(FalseValue))
if (FVPN->getParent() == FalseSucc)
FalseValue = FVPN->getIncomingValueForBlock(BI->getParent());
-
+
// In order for this transformation to be safe, we must be able to
// unconditionally execute both operands to the return. This is
// normally the case, but we could have a potentially-trapping
@@ -1472,12 +1472,12 @@
if (ConstantExpr *FCV = dyn_cast_or_null<ConstantExpr>(FalseValue))
if (FCV->canTrap())
return false;
-
+
// Okay, we collected all the mapped values and checked them for sanity, and
// defined to really do this transformation. First, update the CFG.
TrueSucc->removePredecessor(BI->getParent());
FalseSucc->removePredecessor(BI->getParent());
-
+
// Insert select instructions where needed.
Value *BrCond = BI->getCondition();
if (TrueValue) {
@@ -1491,15 +1491,15 @@
}
}
- Value *RI = !TrueValue ?
+ Value *RI = !TrueValue ?
Builder.CreateRetVoid() : Builder.CreateRet(TrueValue);
(void) RI;
-
+
DEBUG(dbgs() << "\nCHANGING BRANCH TO TWO RETURNS INTO SELECT:"
<< "\n " << *BI << "NewRet = " << *RI
<< "TRUEBLOCK: " << *TrueSucc << "FALSEBLOCK: "<< *FalseSucc);
-
+
EraseTerminatorInstAndDCECond(BI);
return true;
@@ -1600,7 +1600,7 @@
if (Cond == 0)
return false;
}
-
+
if (Cond == 0 || (!isa<CmpInst>(Cond) && !isa<BinaryOperator>(Cond)) ||
Cond->getParent() != BB || !Cond->hasOneUse())
return false;
@@ -1623,7 +1623,7 @@
isSafeToSpeculativelyExecute(FrontIt)) {
BonusInst = &*FrontIt;
++FrontIt;
-
+
// Ignore dbg intrinsics.
while (isa<DbgInfoIntrinsic>(FrontIt)) ++FrontIt;
}
@@ -1631,13 +1631,13 @@
// Only a single bonus inst is allowed.
if (&*FrontIt != Cond)
return false;
-
+
// Make sure the instruction after the condition is the cond branch.
BasicBlock::iterator CondIt = Cond; ++CondIt;
// Ingore dbg intrinsics.
while (isa<DbgInfoIntrinsic>(CondIt)) ++CondIt;
-
+
if (&*CondIt != BI)
return false;
@@ -1649,7 +1649,7 @@
if (ConstantExpr *CE = dyn_cast<ConstantExpr>(Cond->getOperand(1)))
if (CE->canTrap())
return false;
-
+
// Finally, don't infinitely unroll conditional loops.
BasicBlock *TrueDest = BI->getSuccessor(0);
BasicBlock *FalseDest = (BI->isConditional()) ? BI->getSuccessor(1) : 0;
@@ -1659,22 +1659,22 @@
for (pred_iterator PI = pred_begin(BB), E = pred_end(BB); PI != E; ++PI) {
BasicBlock *PredBlock = *PI;
BranchInst *PBI = dyn_cast<BranchInst>(PredBlock->getTerminator());
-
+
// Check that we have two conditional branches. If there is a PHI node in
// the common successor, verify that the same value flows in from both
// blocks.
SmallVector<PHINode*, 4> PHIs;
if (PBI == 0 || PBI->isUnconditional() ||
- (BI->isConditional() &&
+ (BI->isConditional() &&
!SafeToMergeTerminators(BI, PBI)) ||
(!BI->isConditional() &&
!isProfitableToFoldUnconditional(BI, PBI, Cond, PHIs)))
continue;
-
+
// Determine if the two branches share a common destination.
Instruction::BinaryOps Opc;
bool InvertPredCond = false;
-
+
if (BI->isConditional()) {
if (PBI->getSuccessor(0) == TrueDest)
Opc = Instruction::Or;
@@ -1693,7 +1693,7 @@
// Ensure that any values used in the bonus instruction are also used
// by the terminator of the predecessor. This means that those values
- // must already have been resolved, so we won't be inhibiting the
+ // must already have been resolved, so we won't be inhibiting the
// out-of-order core by speculating them earlier.
if (BonusInst) {
// Collect the values used by the bonus inst
@@ -1707,47 +1707,47 @@
SmallVector<std::pair<Value*, unsigned>, 4> Worklist;
Worklist.push_back(std::make_pair(PBI->getOperand(0), 0));
-
+
// Walk up to four levels back up the use-def chain of the predecessor's
// terminator to see if all those values were used. The choice of four
// levels is arbitrary, to provide a compile-time-cost bound.
while (!Worklist.empty()) {
std::pair<Value*, unsigned> Pair = Worklist.back();
Worklist.pop_back();
-
+
if (Pair.second >= 4) continue;
UsedValues.erase(Pair.first);
if (UsedValues.empty()) break;
-
+
if (Instruction *I = dyn_cast<Instruction>(Pair.first)) {
for (Instruction::op_iterator OI = I->op_begin(), OE = I->op_end();
OI != OE; ++OI)
Worklist.push_back(std::make_pair(OI->get(), Pair.second+1));
- }
+ }
}
-
+
if (!UsedValues.empty()) return false;
}
DEBUG(dbgs() << "FOLDING BRANCH TO COMMON DEST:\n" << *PBI << *BB);
- IRBuilder<> Builder(PBI);
+ IRBuilder<> Builder(PBI);
// If we need to invert the condition in the pred block to match, do so now.
if (InvertPredCond) {
Value *NewCond = PBI->getCondition();
-
+
if (NewCond->hasOneUse() && isa<CmpInst>(NewCond)) {
CmpInst *CI = cast<CmpInst>(NewCond);
CI->setPredicate(CI->getInversePredicate());
} else {
- NewCond = Builder.CreateNot(NewCond,
+ NewCond = Builder.CreateNot(NewCond,
PBI->getCondition()->getName()+".not");
}
-
+
PBI->setCondition(NewCond);
PBI->swapSuccessors();
}
-
+
// If we have a bonus inst, clone it into the predecessor block.
Instruction *NewBonus = 0;
if (BonusInst) {
@@ -1756,7 +1756,7 @@
NewBonus->takeName(BonusInst);
BonusInst->setName(BonusInst->getName()+".old");
}
-
+
// Clone Cond into the predecessor basic block, and or/and the
// two conditions together.
Instruction *New = Cond->clone();
@@ -1764,9 +1764,9 @@
PredBlock->getInstList().insert(PBI, New);
New->takeName(Cond);
Cond->setName(New->getName()+".old");
-
+
if (BI->isConditional()) {
- Instruction *NewCond =
+ Instruction *NewCond =
cast<Instruction>(Builder.CreateBinOp(Opc, PBI->getCondition(),
New, "or.cond"));
PBI->setCondition(NewCond);
@@ -1806,7 +1806,7 @@
// Create (PBI_Cond and BI_Value) or (!PBI_Cond and PBI_C)
// PBI_C is true: (PBI_Cond and BI_Value) or (!PBI_Cond)
// is false: PBI_Cond and BI_Value
- MergedCond =
+ MergedCond =
cast<Instruction>(Builder.CreateBinOp(Instruction::And,
PBI->getCondition(), New,
"and.cond"));
@@ -1814,7 +1814,7 @@
Instruction *NotCond =
cast<Instruction>(Builder.CreateNot(PBI->getCondition(),
"not.cond"));
- MergedCond =
+ MergedCond =
cast<Instruction>(Builder.CreateBinOp(Instruction::Or,
NotCond, MergedCond,
"or.cond"));
@@ -1921,7 +1921,7 @@
for (BasicBlock::iterator I = BB->begin(), E = BB->end(); I != E; ++I)
if (isa<DbgInfoIntrinsic>(*I))
I->clone()->insertBefore(PBI);
-
+
return true;
}
return false;
@@ -1936,7 +1936,7 @@
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
+ // predecessor that ends on a branch of the same condition, make
// this conditional branch redundant.
if (PBI->getCondition() == BI->getCondition() &&
PBI->getSuccessor(0) != PBI->getSuccessor(1)) {
@@ -1945,11 +1945,11 @@
if (BB->getSinglePredecessor()) {
// Turn this into a branch on constant.
bool CondIsTrue = PBI->getSuccessor(0) == BB;
- BI->setCondition(ConstantInt::get(Type::getInt1Ty(BB->getContext()),
+ BI->setCondition(ConstantInt::get(Type::getInt1Ty(BB->getContext()),
CondIsTrue));
return true; // Nuke the branch on constant.
}
-
+
// Otherwise, if there are multiple predecessors, insert a PHI that merges
// in the constant and simplify the block result. Subsequent passes of
// simplifycfg will thread the block.
@@ -1969,18 +1969,18 @@
PBI->getCondition() == BI->getCondition() &&
PBI->getSuccessor(0) != PBI->getSuccessor(1)) {
bool CondIsTrue = PBI->getSuccessor(0) == BB;
- NewPN->addIncoming(ConstantInt::get(Type::getInt1Ty(BB->getContext()),
+ NewPN->addIncoming(ConstantInt::get(Type::getInt1Ty(BB->getContext()),
CondIsTrue), P);
} else {
NewPN->addIncoming(BI->getCondition(), P);
}
}
-
+
BI->setCondition(NewPN);
return true;
}
}
-
+
// If this is a conditional branch in an empty block, and if any
// predecessors is a conditional branch to one of our destinations,
// fold the conditions into logical ops and one cond br.
@@ -1991,11 +1991,11 @@
if (&*BBI != BI)
return false;
-
+
if (ConstantExpr *CE = dyn_cast<ConstantExpr>(BI->getCondition()))
if (CE->canTrap())
return false;
-
+
int PBIOp, BIOp;
if (PBI->getSuccessor(0) == BI->getSuccessor(0))
PBIOp = BIOp = 0;
@@ -2007,31 +2007,31 @@
PBIOp = BIOp = 1;
else
return false;
-
+
// Check to make sure that the other destination of this branch
// isn't BB itself. If so, this is an infinite loop that will
// keep getting unwound.
if (PBI->getSuccessor(PBIOp) == BB)
return false;
-
- // Do not perform this transformation if it would require
+
+ // Do not perform this transformation if it would require
// insertion of a large number of select instructions. For targets
// without predication/cmovs, this is a big pessimization.
BasicBlock *CommonDest = PBI->getSuccessor(PBIOp);
-
+
unsigned NumPhis = 0;
for (BasicBlock::iterator II = CommonDest->begin();
isa<PHINode>(II); ++II, ++NumPhis)
if (NumPhis > 2) // Disable this xform.
return false;
-
+
// Finally, if everything is ok, fold the branches to logical ops.
BasicBlock *OtherDest = BI->getSuccessor(BIOp ^ 1);
-
+
DEBUG(dbgs() << "FOLDING BRs:" << *PBI->getParent()
<< "AND: " << *BI->getParent());
-
-
+
+
// If OtherDest *is* BB, then BB is a basic block with a single conditional
// branch in it, where one edge (OtherDest) goes back to itself but the other
// exits. We don't *know* that the program avoids the infinite loop
@@ -2046,13 +2046,13 @@
"infloop", BB->getParent());
BranchInst::Create(InfLoopBlock, InfLoopBlock);
OtherDest = InfLoopBlock;
- }
-
+ }
+
DEBUG(dbgs() << *PBI->getParent()->getParent());
// BI may have other predecessors. Because of this, we leave
// it alone, but modify PBI.
-
+
// Make sure we get to CommonDest on True&True directions.
Value *PBICond = PBI->getCondition();
IRBuilder<true, NoFolder> Builder(PBI);
@@ -2065,16 +2065,16 @@
// Merge the conditions.
Value *Cond = Builder.CreateOr(PBICond, BICond, "brmerge");
-
+
// Modify PBI to branch on the new condition to the new dests.
PBI->setCondition(Cond);
PBI->setSuccessor(0, CommonDest);
PBI->setSuccessor(1, OtherDest);
-
+
// OtherDest may have phi nodes. If so, add an entry from PBI's
// block that are identical to the entries for BI's block.
AddPredecessorToBlock(OtherDest, PBI->getParent(), BB);
-
+
// We know that the CommonDest already had an edge from PBI to
// it. If it has PHIs though, the PHIs may have different
// entries for BB and PBI's BB. If so, insert a select to make
@@ -2092,10 +2092,10 @@
PN->setIncomingValue(PBBIdx, NV);
}
}
-
+
DEBUG(dbgs() << "INTO: " << *PBI->getParent());
DEBUG(dbgs() << *PBI->getParent()->getParent());
-
+
// This basic block is probably dead. We know it has at least
// one fewer predecessor.
return true;
@@ -2214,7 +2214,7 @@
/// br label %end
/// end:
/// ... = phi i1 [ true, %entry ], [ %tmp, %DEFAULT ], [ true, %entry ]
-///
+///
/// We prefer to split the edge to 'end' so that there is a true/false entry to
/// the PHI, merging the third icmp into the switch.
static bool TryToSimplifyUncondBranchWithICmpInIt(ICmpInst *ICI,
@@ -2228,17 +2228,17 @@
Value *V = ICI->getOperand(0);
ConstantInt *Cst = cast<ConstantInt>(ICI->getOperand(1));
-
+
// The pattern we're looking for is where our only predecessor is a switch on
// 'V' and this block is the default case for the switch. In this case we can
// fold the compared value into the switch to simplify things.
BasicBlock *Pred = BB->getSinglePredecessor();
if (Pred == 0 || !isa<SwitchInst>(Pred->getTerminator())) return false;
-
+
SwitchInst *SI = cast<SwitchInst>(Pred->getTerminator());
if (SI->getCondition() != V)
return false;
-
+
// If BB is reachable on a non-default case, then we simply know the value of
// V in this block. Substitute it and constant fold the icmp instruction
// away.
@@ -2246,7 +2246,7 @@
ConstantInt *VVal = SI->findCaseDest(BB);
assert(VVal && "Should have a unique destination value");
ICI->setOperand(0, VVal);
-
+
if (Value *V = SimplifyInstruction(ICI, TD)) {
ICI->replaceAllUsesWith(V);
ICI->eraseFromParent();
@@ -2254,7 +2254,7 @@
// BB is now empty, so it is likely to simplify away.
return SimplifyCFG(BB) | true;
}
-
+
// Ok, the block is reachable from the default dest. If the constant we're
// comparing exists in one of the other edges, then we can constant fold ICI
// and zap it.
@@ -2264,13 +2264,13 @@
V = ConstantInt::getFalse(BB->getContext());
else
V = ConstantInt::getTrue(BB->getContext());
-
+
ICI->replaceAllUsesWith(V);
ICI->eraseFromParent();
// BB is now empty, so it is likely to simplify away.
return SimplifyCFG(BB) | true;
}
-
+
// The use of the icmp has to be in the 'end' block, by the only PHI node in
// the block.
BasicBlock *SuccBlock = BB->getTerminator()->getSuccessor(0);
@@ -2297,7 +2297,7 @@
BasicBlock *NewBB = BasicBlock::Create(BB->getContext(), "switch.edge",
BB->getParent(), BB);
SI->addCase(Cst, NewBB);
-
+
// NewBB branches to the phi block, add the uncond branch and the phi entry.
Builder.SetInsertPoint(NewBB);
Builder.SetCurrentDebugLocation(SI->getDebugLoc());
@@ -2313,8 +2313,8 @@
IRBuilder<> &Builder) {
Instruction *Cond = dyn_cast<Instruction>(BI->getCondition());
if (Cond == 0) return false;
-
-
+
+
// Change br (X == 0 | X == 1), T, F into a switch instruction.
// If this is a bunch of seteq's or'd together, or if it's a bunch of
// 'setne's and'ed together, collect them.
@@ -2323,7 +2323,7 @@
bool TrueWhenEqual = true;
Value *ExtraCase = 0;
unsigned UsedICmps = 0;
-
+
if (Cond->getOpcode() == Instruction::Or) {
CompVal = GatherConstantCompares(Cond, Values, ExtraCase, TD, true,
UsedICmps);
@@ -2332,7 +2332,7 @@
UsedICmps);
TrueWhenEqual = false;
}
-
+
// If we didn't have a multiply compared value, fail.
if (CompVal == 0) return false;
@@ -2344,21 +2344,21 @@
// instruction can't handle, remove them now.
array_pod_sort(Values.begin(), Values.end(), ConstantIntSortPredicate);
Values.erase(std::unique(Values.begin(), Values.end()), Values.end());
-
+
// If Extra was used, we require at least two switch values to do the
// transformation. A switch with one value is just an cond branch.
if (ExtraCase && Values.size() < 2) return false;
-
+
// Figure out which block is which destination.
BasicBlock *DefaultBB = BI->getSuccessor(1);
BasicBlock *EdgeBB = BI->getSuccessor(0);
if (!TrueWhenEqual) std::swap(DefaultBB, EdgeBB);
-
+
BasicBlock *BB = BI->getParent();
-
+
DEBUG(dbgs() << "Converting 'icmp' chain with " << Values.size()
<< " cases into SWITCH. BB is:\n" << *BB);
-
+
// If there are any extra values that couldn't be folded into the switch
// then we evaluate them with an explicit branch first. Split the block
// right before the condbr to handle it.
@@ -2372,13 +2372,13 @@
Builder.CreateCondBr(ExtraCase, EdgeBB, NewBB);
else
Builder.CreateCondBr(ExtraCase, NewBB, EdgeBB);
-
+
OldTI->eraseFromParent();
-
+
// If there are PHI nodes in EdgeBB, then we need to add a new entry to them
// for the edge we just added.
AddPredecessorToBlock(EdgeBB, BB, NewBB);
-
+
DEBUG(dbgs() << " ** 'icmp' chain unhandled condition: " << *ExtraCase
<< "\nEXTRABB = " << *BB);
BB = NewBB;
@@ -2392,14 +2392,14 @@
TD->getIntPtrType(CompVal->getContext()),
"magicptr");
}
-
+
// Create the new switch instruction now.
SwitchInst *New = Builder.CreateSwitch(CompVal, DefaultBB, Values.size());
// Add all of the 'cases' to the switch instruction.
for (unsigned i = 0, e = Values.size(); i != e; ++i)
New->addCase(Values[i], EdgeBB);
-
+
// We added edges from PI to the EdgeBB. As such, if there were any
// PHI nodes in EdgeBB, they need entries to be added corresponding to
// the number of edges added.
@@ -2410,10 +2410,10 @@
for (unsigned i = 0, e = Values.size()-1; i != e; ++i)
PN->addIncoming(InVal, BB);
}
-
+
// Erase the old branch instruction.
EraseTerminatorInstAndDCECond(BI);
-
+
DEBUG(dbgs() << " ** 'icmp' chain result is:\n" << *BB << '\n');
return true;
}
@@ -2467,7 +2467,7 @@
bool SimplifyCFGOpt::SimplifyReturn(ReturnInst *RI, IRBuilder<> &Builder) {
BasicBlock *BB = RI->getParent();
if (!BB->getFirstNonPHIOrDbg()->isTerminator()) return false;
-
+
// Find predecessors that end with branches.
SmallVector<BasicBlock*, 8> UncondBranchPreds;
SmallVector<BranchInst*, 8> CondBranchPreds;
@@ -2481,7 +2481,7 @@
CondBranchPreds.push_back(BI);
}
}
-
+
// If we found some, do the transformation!
if (!UncondBranchPreds.empty() && DupRet) {
while (!UncondBranchPreds.empty()) {
@@ -2490,21 +2490,21 @@
<< "INTO UNCOND BRANCH PRED: " << *Pred);
(void)FoldReturnIntoUncondBranch(RI, BB, Pred);
}
-
+
// If we eliminated all predecessors of the block, delete the block now.
if (pred_begin(BB) == pred_end(BB))
// We know there are no successors, so just nuke the block.
BB->eraseFromParent();
-
+
return true;
}
-
+
// Check out all of the conditional branches going to this return
// instruction. If any of them just select between returns, change the
// branch itself into a select/return pair.
while (!CondBranchPreds.empty()) {
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()) &&
isa<ReturnInst>(BI->getSuccessor(1)->getTerminator()) &&
@@ -2516,9 +2516,9 @@
bool SimplifyCFGOpt::SimplifyUnreachable(UnreachableInst *UI) {
BasicBlock *BB = UI->getParent();
-
+
bool Changed = false;
-
+
// If there are any instructions immediately before the unreachable that can
// be removed, do so.
while (UI != BB->begin()) {
@@ -2558,11 +2558,11 @@
BBI->eraseFromParent();
Changed = true;
}
-
+
// If the unreachable instruction is the first in the block, take a gander
// at all of the predecessors of this instruction, and simplify them.
if (&BB->front() != UI) return Changed;
-
+
SmallVector<BasicBlock*, 8> Preds(pred_begin(BB), pred_end(BB));
for (unsigned i = 0, e = Preds.size(); i != e; ++i) {
TerminatorInst *TI = Preds[i]->getTerminator();
@@ -2615,7 +2615,7 @@
BasicBlock *MaxBlock = 0;
for (std::map<BasicBlock*, std::pair<unsigned, unsigned> >::iterator
I = Popularity.begin(), E = Popularity.end(); I != E; ++I) {
- if (I->second.first > MaxPop ||
+ if (I->second.first > MaxPop ||
(I->second.first == MaxPop && MaxIndex > I->second.second)) {
MaxPop = I->second.first;
MaxIndex = I->second.second;
@@ -2627,13 +2627,13 @@
// edges to it.
SI->setDefaultDest(MaxBlock);
Changed = true;
-
+
// If MaxBlock has phinodes in it, remove MaxPop-1 entries from
// it.
if (isa<PHINode>(MaxBlock->begin()))
for (unsigned i = 0; i != MaxPop-1; ++i)
MaxBlock->removePredecessor(SI->getParent());
-
+
for (SwitchInst::CaseIt i = SI->case_begin(), e = SI->case_end();
i != e; ++i)
if (i.getCaseSuccessor() == MaxBlock) {
@@ -2648,7 +2648,7 @@
// place to note that the call does not throw though.
BranchInst *BI = Builder.CreateBr(II->getNormalDest());
II->removeFromParent(); // Take out of symbol table
-
+
// Insert the call now...
SmallVector<Value*, 8> Args(II->op_begin(), II->op_end()-3);
Builder.SetInsertPoint(BI);
@@ -2663,7 +2663,7 @@
}
}
}
-
+
// If this block is now dead, remove it.
if (pred_begin(BB) == pred_end(BB) &&
BB != &BB->getParent()->getEntryBlock()) {
@@ -2868,7 +2868,7 @@
bool SimplifyCFGOpt::SimplifyIndirectBr(IndirectBrInst *IBI) {
BasicBlock *BB = IBI->getParent();
bool Changed = false;
-
+
// Eliminate redundant destinations.
SmallPtrSet<Value *, 8> Succs;
for (unsigned i = 0, e = IBI->getNumDestinations(); i != e; ++i) {
@@ -2879,7 +2879,7 @@
--i; --e;
Changed = true;
}
- }
+ }
if (IBI->getNumDestinations() == 0) {
// If the indirectbr has no successors, change it to unreachable.
@@ -2887,14 +2887,14 @@
EraseTerminatorInstAndDCECond(IBI);
return true;
}
-
+
if (IBI->getNumDestinations() == 1) {
// If the indirectbr has one successor, change it to a direct branch.
BranchInst::Create(IBI->getDestination(0), IBI);
EraseTerminatorInstAndDCECond(IBI);
return true;
}
-
+
if (SelectInst *SI = dyn_cast<SelectInst>(IBI->getAddress())) {
if (SimplifyIndirectBrOnSelect(IBI, SI))
return SimplifyCFG(BB) | true;
@@ -2904,13 +2904,13 @@
bool SimplifyCFGOpt::SimplifyUncondBranch(BranchInst *BI, IRBuilder<> &Builder){
BasicBlock *BB = BI->getParent();
-
+
// If the Terminator is the only non-phi instruction, simplify the block.
BasicBlock::iterator I = BB->getFirstNonPHIOrDbgOrLifetime();
if (I->isTerminator() && BB != &BB->getParent()->getEntryBlock() &&
TryToSimplifyUncondBranchFromEmptyBlock(BB))
return true;
-
+
// If the only instruction in the block is a seteq/setne comparison
// against a constant, try to simplify the block.
if (ICmpInst *ICI = dyn_cast<ICmpInst>(I))
@@ -2921,7 +2921,7 @@
TryToSimplifyUncondBranchWithICmpInIt(ICI, TD, Builder))
return true;
}
-
+
// If this basic block is ONLY a compare and a branch, and if a predecessor
// branches to us and our successor, fold the comparison into the
// predecessor and use logical operations to update the incoming value
@@ -2934,7 +2934,7 @@
bool SimplifyCFGOpt::SimplifyCondBranch(BranchInst *BI, IRBuilder<> &Builder) {
BasicBlock *BB = BI->getParent();
-
+
// Conditional branch
if (isValueEqualityComparison(BI)) {
// If we only have one predecessor, and if it is a branch on this value,
@@ -2943,7 +2943,7 @@
if (BasicBlock *OnlyPred = BB->getSinglePredecessor())
if (SimplifyEqualityComparisonWithOnlyPredecessor(BI, OnlyPred, Builder))
return SimplifyCFG(BB) | true;
-
+
// This block must be empty, except for the setcond inst, if it exists.
// Ignore dbg intrinsics.
BasicBlock::iterator I = BB->begin();
@@ -2962,17 +2962,17 @@
return SimplifyCFG(BB) | true;
}
}
-
+
// Try to turn "br (X == 0 | X == 1), T, F" into a switch instruction.
if (SimplifyBranchOnICmpChain(BI, TD, Builder))
return true;
-
+
// If this basic block is ONLY a compare and a branch, and if a predecessor
// branches to us and one of our successors, fold the comparison into the
// predecessor and use logical operations to pick the right destination.
if (FoldBranchToCommonDest(BI))
return SimplifyCFG(BB) | true;
-
+
// We have a conditional branch to two blocks that are only reachable
// from BI. We know that the condbr dominates the two blocks, so see if
// there is any identical code in the "then" and "else" blocks. If so, we
@@ -2999,14 +2999,14 @@
if (SpeculativelyExecuteBB(BI, BI->getSuccessor(1)))
return SimplifyCFG(BB) | true;
}
-
+
// If this is a branch on a phi node in the current block, thread control
// through this block if any PHI node entries are constants.
if (PHINode *PN = dyn_cast<PHINode>(BI->getCondition()))
if (PN->getParent() == BI->getParent())
if (FoldCondBranchOnPHI(BI, TD))
return SimplifyCFG(BB) | true;
-
+
// Scan predecessor blocks for conditional branches.
for (pred_iterator PI = pred_begin(BB), E = pred_end(BB); PI != E; ++PI)
if (BranchInst *PBI = dyn_cast<BranchInst>((*PI)->getTerminator()))
@@ -3114,7 +3114,7 @@
//
if (MergeBlockIntoPredecessor(BB))
return true;
-
+
IRBuilder<> Builder(BB);
// If there is a trivial two-entry PHI node in this basic block, and we can
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