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Unified Diff: lib/CodeGen/BranchFolding.cpp

Issue 96065: non inline jumptables for arm Base URL: http://llvm.org/svn/llvm-project/llvm/trunk/
Patch Set: attempt at thumb suppport, undid refactoring Created 14 years, 7 months ago
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Index: lib/CodeGen/BranchFolding.cpp
===================================================================
--- lib/CodeGen/BranchFolding.cpp (revision 78188)
+++ lib/CodeGen/BranchFolding.cpp (working copy)
@@ -18,6 +18,7 @@
#define DEBUG_TYPE "branchfolding"
#include "llvm/CodeGen/Passes.h"
+#include "llvm/CodeGen/MachineConstantPool.h"
#include "llvm/CodeGen/MachineModuleInfo.h"
#include "llvm/CodeGen/MachineFunctionPass.h"
#include "llvm/CodeGen/MachineJumpTableInfo.h"
@@ -37,18 +38,18 @@
STATISTIC(NumDeadBlocks, "Number of dead blocks removed");
STATISTIC(NumBranchOpts, "Number of branches optimized");
STATISTIC(NumTailMerge , "Number of block tails merged");
-static cl::opt<cl::boolOrDefault> FlagEnableTailMerge("enable-tail-merge",
+static cl::opt<cl::boolOrDefault> FlagEnableTailMerge("enable-tail-merge",
cl::init(cl::BOU_UNSET), cl::Hidden);
// Throttle for huge numbers of predecessors (compile speed problems)
static cl::opt<unsigned>
-TailMergeThreshold("tail-merge-threshold",
+TailMergeThreshold("tail-merge-threshold",
cl::desc("Max number of predecessors to consider tail merging"),
cl::init(150), cl::Hidden);
namespace {
struct VISIBILITY_HIDDEN BranchFolder : public MachineFunctionPass {
static char ID;
- explicit BranchFolder(bool defaultEnableTailMerge) :
+ explicit BranchFolder(bool defaultEnableTailMerge) :
MachineFunctionPass(&ID) {
switch (FlagEnableTailMerge) {
case cl::BOU_UNSET: EnableTailMerge = defaultEnableTailMerge; break;
@@ -92,7 +93,7 @@
void OptimizeBlock(MachineBasicBlock *MBB);
void RemoveDeadBlock(MachineBasicBlock *MBB);
bool OptimizeImpDefsBlock(MachineBasicBlock *MBB);
-
+
bool CanFallThrough(MachineBasicBlock *CurBB);
bool CanFallThrough(MachineBasicBlock *CurBB, bool BranchUnAnalyzable,
MachineBasicBlock *TBB, MachineBasicBlock *FBB,
@@ -101,7 +102,7 @@
char BranchFolder::ID = 0;
}
-FunctionPass *llvm::createBranchFoldingPass(bool DefaultEnableTailMerge) {
+FunctionPass *llvm::createBranchFoldingPass(bool DefaultEnableTailMerge) {
return new BranchFolder(DefaultEnableTailMerge); }
/// RemoveDeadBlock - Remove the specified dead machine basic block from the
@@ -109,12 +110,12 @@
void BranchFolder::RemoveDeadBlock(MachineBasicBlock *MBB) {
assert(MBB->pred_empty() && "MBB must be dead!");
DOUT << "\nRemoving MBB: " << *MBB;
-
+
MachineFunction *MF = MBB->getParent();
// drop all successors.
while (!MBB->succ_empty())
MBB->removeSuccessor(MBB->succ_end()-1);
-
+
// If there are any labels in the basic block, unregister them from
// MachineModuleInfo.
if (MMI && !MBB->empty()) {
@@ -125,7 +126,7 @@
MMI->InvalidateLabel(I->getOperand(0).getImm());
}
}
-
+
// Remove the block.
MF->erase(MBB);
}
@@ -217,7 +218,7 @@
// Figure out how these jump tables should be merged.
std::vector<unsigned> JTMapping;
JTMapping.reserve(JTs.size());
-
+
// We always keep the 0th jump table.
JTMapping.push_back(0);
@@ -225,7 +226,7 @@
// is N^2, which should be fixed someday.
for (unsigned i = 1, e = JTs.size(); i != e; ++i)
JTMapping.push_back(JTI->getJumpTableIndex(JTs[i].MBBs));
-
+
// If a jump table was merge with another one, walk the function rewriting
// references to jump tables to reference the new JT ID's. Keep track of
// whether we see a jump table idx, if not, we can delete the JT.
@@ -237,14 +238,29 @@
for (unsigned op = 0, e = I->getNumOperands(); op != e; ++op) {
MachineOperand &Op = I->getOperand(op);
if (!Op.isJTI()) continue;
- unsigned NewIdx = JTMapping[Op.getIndex()];
+ // Remap index.
+ const unsigned NewIdx = JTMapping[Op.getIndex()];
Op.setIndex(NewIdx);
-
// Remember that this JT is live.
JTIsLive.set(NewIdx);
}
}
-
+
+ // This currently only used on ARM targets where the ConstantPool
+ // subclass is overloading getJumpTableIndex()
+ const std::vector<MachineConstantPoolEntry>& CPs =
+ MF.getConstantPool()->getConstants();
+ for (unsigned i = 0, e = CPs.size(); i != e; ++i) {
+ if (!CPs[i].isMachineConstantPoolEntry()) continue;
+ unsigned *JTIndex = CPs[i].Val.MachineCPVal->getJumpTableIndex();
+ if (!JTIndex) continue;
+ // Remap index.
+ const unsigned NewIdx = JTMapping[*JTIndex];
+ *JTIndex = NewIdx;
+ // Remember that this JT is live.
+ JTIsLive.set(NewIdx);
+ }
+
// Finally, remove dead jump tables. This happens either because the
// indirect jump was unreachable (and thus deleted) or because the jump
// table was merged with some other one.
@@ -254,7 +270,7 @@
EverMadeChange = true;
}
}
-
+
delete RS;
return EverMadeChange;
}
@@ -268,7 +284,7 @@
unsigned Hash = MI->getOpcode();
for (unsigned i = 0, e = MI->getNumOperands(); i != e; ++i) {
const MachineOperand &Op = MI->getOperand(i);
-
+
// Merge in bits from the operand if easy.
unsigned OperandHash = 0;
switch (Op.getType()) {
@@ -290,15 +306,15 @@
break;
default: break;
}
-
+
Hash += ((OperandHash << 3) | Op.getType()) << (i&31);
}
return Hash;
}
/// HashEndOfMBB - Hash the last few instructions in the MBB. For blocks
-/// with no successors, we hash two instructions, because cross-jumping
-/// only saves code when at least two instructions are removed (since a
+/// with no successors, we hash two instructions, because cross-jumping
+/// only saves code when at least two instructions are removed (since a
/// branch must be inserted). For blocks with a successor, one of the
/// two blocks to be tail-merged will end with a branch already, so
/// it gains to cross-jump even for one instruction.
@@ -308,13 +324,13 @@
MachineBasicBlock::const_iterator I = MBB->end();
if (I == MBB->begin())
return 0; // Empty MBB.
-
+
--I;
unsigned Hash = HashMachineInstr(I);
-
+
if (I == MBB->begin() || minCommonTailLength == 1)
return Hash; // Single instr MBB.
-
+
--I;
// Hash in the second-to-last instruction.
Hash ^= HashMachineInstr(I) << 2;
@@ -330,11 +346,11 @@
MachineBasicBlock::iterator &I2) {
I1 = MBB1->end();
I2 = MBB2->end();
-
+
unsigned TailLen = 0;
while (I1 != MBB1->begin() && I2 != MBB2->begin()) {
--I1; --I2;
- if (!I1->isIdenticalTo(I2) ||
+ if (!I1->isIdenticalTo(I2) ||
// FIXME: This check is dubious. It's used to get around a problem where
// people incorrectly expect inline asm directives to remain in the same
// relative order. This is untenable because normal compiler
@@ -355,11 +371,11 @@
void BranchFolder::ReplaceTailWithBranchTo(MachineBasicBlock::iterator OldInst,
MachineBasicBlock *NewDest) {
MachineBasicBlock *OldBB = OldInst->getParent();
-
+
// Remove all the old successors of OldBB from the CFG.
while (!OldBB->succ_empty())
OldBB->removeSuccessor(OldBB->succ_begin());
-
+
// Remove all the dead instructions from the end of OldBB.
OldBB->erase(OldInst, OldBB->end());
@@ -384,10 +400,10 @@
// Move all the successors of this block to the specified block.
NewMBB->transferSuccessors(&CurMBB);
-
+
// Add an edge from CurMBB to NewMBB for the fall-through.
CurMBB.addSuccessor(NewMBB);
-
+
// Splice the code over.
NewMBB->splice(NewMBB->end(), &CurMBB, BBI1, CurMBB.end());
@@ -469,23 +485,23 @@
}
/// ComputeSameTails - Look through all the blocks in MergePotentials that have
-/// hash CurHash (guaranteed to match the last element). Build the vector
+/// hash CurHash (guaranteed to match the last element). Build the vector
/// SameTails of all those that have the (same) largest number of instructions
/// in common of any pair of these blocks. SameTails entries contain an
-/// iterator into MergePotentials (from which the MachineBasicBlock can be
-/// found) and a MachineBasicBlock::iterator into that MBB indicating the
+/// iterator into MergePotentials (from which the MachineBasicBlock can be
+/// found) and a MachineBasicBlock::iterator into that MBB indicating the
/// instruction where the matching code sequence begins.
/// Order of elements in SameTails is the reverse of the order in which
/// those blocks appear in MergePotentials (where they are not necessarily
/// consecutive).
-unsigned BranchFolder::ComputeSameTails(unsigned CurHash,
+unsigned BranchFolder::ComputeSameTails(unsigned CurHash,
unsigned minCommonTailLength) {
unsigned maxCommonTailLength = 0U;
SameTails.clear();
MachineBasicBlock::iterator TrialBBI1, TrialBBI2;
MPIterator HighestMPIter = prior(MergePotentials.end());
for (MPIterator CurMPIter = prior(MergePotentials.end()),
- B = MergePotentials.begin();
+ B = MergePotentials.begin();
CurMPIter!=B && CurMPIter->first==CurHash;
--CurMPIter) {
for (MPIterator I = prior(CurMPIter); I->first==CurHash ; --I) {
@@ -524,11 +540,11 @@
/// RemoveBlocksWithHash - Remove all blocks with hash CurHash from
/// MergePotentials, restoring branches at ends of blocks as appropriate.
-void BranchFolder::RemoveBlocksWithHash(unsigned CurHash,
+void BranchFolder::RemoveBlocksWithHash(unsigned CurHash,
MachineBasicBlock* SuccBB,
MachineBasicBlock* PredBB) {
MPIterator CurMPIter, B;
- for (CurMPIter = prior(MergePotentials.end()), B = MergePotentials.begin();
+ for (CurMPIter = prior(MergePotentials.end()), B = MergePotentials.begin();
CurMPIter->first==CurHash;
--CurMPIter) {
// Put the unconditional branch back, if we need one.
@@ -557,7 +573,7 @@
}
// Otherwise, make a (fairly bogus) choice based on estimate of
// how long it will take the various blocks to execute.
- unsigned t = EstimateRuntime(SameTails[i].first->second->begin(),
+ unsigned t = EstimateRuntime(SameTails[i].first->second->begin(),
SameTails[i].second);
if (t<=TimeEstimate) {
TimeEstimate = t;
@@ -568,7 +584,7 @@
MachineBasicBlock::iterator BBI = SameTails[commonTailIndex].second;
MachineBasicBlock *MBB = SameTails[commonTailIndex].first->second;
- DOUT << "\nSplitting " << MBB->getNumber() << ", size " <<
+ DOUT << "\nSplitting " << MBB->getNumber() << ", size " <<
maxCommonTailLength;
MachineBasicBlock *newMBB = SplitMBBAt(*MBB, BBI);
@@ -585,7 +601,7 @@
// successor, or all have no successor) can be tail-merged. If there is a
// successor, any blocks in MergePotentials that are not tail-merged and
// are not immediately before Succ must have an unconditional branch to
-// Succ added (but the predecessor/successor lists need no adjustment).
+// Succ added (but the predecessor/successor lists need no adjustment).
// The lone predecessor of Succ that falls through into Succ,
// if any, is given in PredBB.
@@ -596,7 +612,7 @@
// FIXME: Ask the target to provide the threshold?
unsigned minCommonTailLength = (SuccBB ? 1 : 2) + 1;
MadeChange = false;
-
+
DOUT << "\nTryMergeBlocks " << MergePotentials.size() << '\n';
// Sort by hash value so that blocks with identical end sequences sort
@@ -606,13 +622,13 @@
// Walk through equivalence sets looking for actual exact matches.
while (MergePotentials.size() > 1) {
unsigned CurHash = prior(MergePotentials.end())->first;
-
+
// Build SameTails, identifying the set of blocks with this hash code
// and with the maximum number of instructions in common.
- unsigned maxCommonTailLength = ComputeSameTails(CurHash,
+ unsigned maxCommonTailLength = ComputeSameTails(CurHash,
minCommonTailLength);
- // If we didn't find any pair that has at least minCommonTailLength
+ // If we didn't find any pair that has at least minCommonTailLength
// instructions in common, remove all blocks with this hash code and retry.
if (SameTails.empty()) {
RemoveBlocksWithHash(CurHash, SuccBB, PredBB);
@@ -665,7 +681,7 @@
bool BranchFolder::TailMergeBlocks(MachineFunction &MF) {
if (!EnableTailMerge) return false;
-
+
MadeChange = false;
// First find blocks with no successors.
@@ -684,7 +700,7 @@
// (1) temporarily removing any unconditional branch from the predecessor
// to IBB, and
// (2) alter conditional branches so they branch to the other block
- // not IBB; this may require adding back an unconditional branch to IBB
+ // not IBB; this may require adding back an unconditional branch to IBB
// later, where there wasn't one coming in. E.g.
// Bcc IBB
// fallthrough to QBB
@@ -703,7 +719,7 @@
MachineBasicBlock *IBB = I;
MachineBasicBlock *PredBB = prior(I);
MergePotentials.clear();
- for (MachineBasicBlock::pred_iterator P = I->pred_begin(),
+ for (MachineBasicBlock::pred_iterator P = I->pred_begin(),
E2 = I->pred_end();
P != E2; ++P) {
MachineBasicBlock* PBB = *P;
@@ -760,7 +776,7 @@
// Reinsert an unconditional branch if needed.
// The 1 below can occur as a result of removing blocks in TryMergeBlocks.
PredBB = prior(I); // this may have been changed in TryMergeBlocks
- if (MergePotentials.size()==1 &&
+ if (MergePotentials.size()==1 &&
MergePotentials.begin()->second != PredBB)
FixTail(MergePotentials.begin()->second, I, TII);
}
@@ -774,14 +790,14 @@
bool BranchFolder::OptimizeBranches(MachineFunction &MF) {
MadeChange = false;
-
+
// Make sure blocks are numbered in order
MF.RenumberBlocks();
for (MachineFunction::iterator I = ++MF.begin(), E = MF.end(); I != E; ) {
MachineBasicBlock *MBB = I++;
OptimizeBlock(MBB);
-
+
// If it is dead, remove it.
if (MBB->pred_empty()) {
RemoveDeadBlock(MBB);
@@ -802,7 +818,7 @@
///
bool BranchFolder::CanFallThrough(MachineBasicBlock *CurBB,
bool BranchUnAnalyzable,
- MachineBasicBlock *TBB,
+ MachineBasicBlock *TBB,
MachineBasicBlock *FBB,
const SmallVectorImpl<MachineOperand> &Cond) {
MachineFunction::iterator Fallthrough = CurBB;
@@ -810,14 +826,14 @@
// If FallthroughBlock is off the end of the function, it can't fall through.
if (Fallthrough == CurBB->getParent()->end())
return false;
-
+
// If FallthroughBlock isn't a successor of CurBB, no fallthrough is possible.
if (!CurBB->isSuccessor(Fallthrough))
return false;
-
+
// If we couldn't analyze the branch, assume it could fall through.
if (BranchUnAnalyzable) return true;
-
+
// If there is no branch, control always falls through.
if (TBB == 0) return true;
@@ -826,11 +842,11 @@
if (MachineFunction::iterator(TBB) == Fallthrough ||
MachineFunction::iterator(FBB) == Fallthrough)
return true;
-
- // If it's an unconditional branch to some block not the fall through, it
+
+ // If it's an unconditional branch to some block not the fall through, it
// doesn't fall through.
if (Cond.empty()) return false;
-
+
// Otherwise, if it is conditional and has no explicit false block, it falls
// through.
return FBB == 0;
@@ -854,14 +870,14 @@
/// fall-through to MBB1 than to fall through into MBB2. This has to return
/// a strict ordering, returning true for both (MBB1,MBB2) and (MBB2,MBB1) will
/// result in infinite loops.
-static bool IsBetterFallthrough(MachineBasicBlock *MBB1,
+static bool IsBetterFallthrough(MachineBasicBlock *MBB1,
MachineBasicBlock *MBB2) {
// Right now, we use a simple heuristic. If MBB2 ends with a call, and
// MBB1 doesn't, we prefer to fall through into MBB1. This allows us to
// optimize branches that branch to either a return block or an assert block
// into a fallthrough to the return.
if (MBB1->empty() || MBB2->empty()) return false;
-
+
// If there is a clear successor ordering we make sure that one block
// will fall through to the next
if (MBB1->isSuccessor(MBB2)) return true;
@@ -877,14 +893,14 @@
void BranchFolder::OptimizeBlock(MachineBasicBlock *MBB) {
MachineFunction::iterator FallThrough = MBB;
++FallThrough;
-
+
// If this block is empty, make everyone use its fall-through, not the block
// explicitly. Landing pads should not do this since the landing-pad table
// points to this block.
if (MBB->empty() && !MBB->isLandingPad()) {
// Dead block? Leave for cleanup later.
if (MBB->pred_empty()) return;
-
+
if (FallThrough == MBB->getParent()->end()) {
// TODO: Simplify preds to not branch here if possible!
} else {
@@ -894,7 +910,7 @@
MachineBasicBlock *Pred = *(MBB->pred_end()-1);
Pred->ReplaceUsesOfBlockWith(MBB, FallThrough);
}
-
+
// If MBB was the target of a jump table, update jump tables to go to the
// fallthrough instead.
MBB->getParent()->getJumpTableInfo()->
@@ -916,20 +932,20 @@
// If the CFG for the prior block has extra edges, remove them.
MadeChange |= PrevBB.CorrectExtraCFGEdges(PriorTBB, PriorFBB,
!PriorCond.empty());
-
+
// If the previous branch is conditional and both conditions go to the same
// destination, remove the branch, replacing it with an unconditional one or
// a fall-through.
if (PriorTBB && PriorTBB == PriorFBB) {
TII->RemoveBranch(PrevBB);
- PriorCond.clear();
+ PriorCond.clear();
if (PriorTBB != MBB)
TII->InsertBranch(PrevBB, PriorTBB, 0, PriorCond);
MadeChange = true;
++NumBranchOpts;
return OptimizeBlock(MBB);
}
-
+
// If the previous branch *only* branches to *this* block (conditional or
// not) remove the branch.
if (PriorTBB == MBB && PriorFBB == 0) {
@@ -938,7 +954,7 @@
++NumBranchOpts;
return OptimizeBlock(MBB);
}
-
+
// If the prior block branches somewhere else on the condition and here if
// the condition is false, remove the uncond second branch.
if (PriorFBB == MBB) {
@@ -948,7 +964,7 @@
++NumBranchOpts;
return OptimizeBlock(MBB);
}
-
+
// If the prior block branches here on true and somewhere else on false, and
// if the branch condition is reversible, reverse the branch to create a
// fall-through.
@@ -962,7 +978,7 @@
return OptimizeBlock(MBB);
}
}
-
+
// If this block doesn't fall through (e.g. it ends with an uncond branch or
// has no successors) and if the pred falls through into this block, and if
// it would otherwise fall through into the block after this, move this
@@ -975,7 +991,7 @@
MachineFunction::iterator(PriorTBB) == FallThrough &&
!CanFallThrough(MBB)) {
bool DoTransform = true;
-
+
// We have to be careful that the succs of PredBB aren't both no-successor
// blocks. If neither have successors and if PredBB is the second from
// last block in the function, we'd just keep swapping the two blocks for
@@ -999,15 +1015,15 @@
if (DoTransform && !MBB->succ_empty() &&
(!CanFallThrough(PriorTBB) || PriorTBB->empty()))
DoTransform = false;
-
-
+
+
if (DoTransform) {
// Reverse the branch so we will fall through on the previous true cond.
SmallVector<MachineOperand, 4> NewPriorCond(PriorCond);
if (!TII->ReverseBranchCondition(NewPriorCond)) {
DOUT << "\nMoving MBB: " << *MBB;
DOUT << "To make fallthrough to: " << *PriorTBB << "\n";
-
+
TII->RemoveBranch(PrevBB);
TII->InsertBranch(PrevBB, MBB, 0, NewPriorCond);
@@ -1020,7 +1036,7 @@
}
}
}
-
+
// Analyze the branch in the current block.
MachineBasicBlock *CurTBB = 0, *CurFBB = 0;
SmallVector<MachineOperand, 4> CurCond;
@@ -1029,7 +1045,7 @@
// If the CFG for the prior block has extra edges, remove them.
MadeChange |= MBB->CorrectExtraCFGEdges(CurTBB, CurFBB, !CurCond.empty());
- // If this is a two-way branch, and the FBB branches to this block, reverse
+ // If this is a two-way branch, and the FBB branches to this block, reverse
// the condition so the single-basic-block loop is faster. Instead of:
// Loop: xxx; jcc Out; jmp Loop
// we want:
@@ -1044,11 +1060,11 @@
return OptimizeBlock(MBB);
}
}
-
-
+
+
// If this branch is the only thing in its block, see if we can forward
// other blocks across it.
- if (CurTBB && CurCond.empty() && CurFBB == 0 &&
+ if (CurTBB && CurCond.empty() && CurFBB == 0 &&
MBB->begin()->getDesc().isBranch() && CurTBB != MBB) {
// This block may contain just an unconditional branch. Because there can
// be 'non-branch terminators' in the block, try removing the branch and
@@ -1066,7 +1082,7 @@
!PrevBB.isSuccessor(MBB)) {
// If the prior block falls through into us, turn it into an
// explicit branch to us to make updates simpler.
- if (!PredHasNoFallThrough && PrevBB.isSuccessor(MBB) &&
+ if (!PredHasNoFallThrough && PrevBB.isSuccessor(MBB) &&
PriorTBB != MBB && PriorFBB != MBB) {
if (PriorTBB == 0) {
assert(PriorCond.empty() && PriorFBB == 0 &&
@@ -1102,7 +1118,7 @@
NewCurFBB, NewCurCond, true);
if (!NewCurUnAnalyzable && NewCurTBB && NewCurTBB == NewCurFBB) {
TII->RemoveBranch(*PMBB);
- NewCurCond.clear();
+ NewCurCond.clear();
TII->InsertBranch(*PMBB, NewCurTBB, 0, NewCurCond);
MadeChange = true;
++NumBranchOpts;
@@ -1121,7 +1137,7 @@
}
}
}
-
+
// Add the branch back if the block is more than just an uncond branch.
TII->InsertBranch(*MBB, CurTBB, 0, CurCond);
}
@@ -1134,7 +1150,7 @@
PriorTBB, PriorFBB, PriorCond)) {
// Now we know that there was no fall-through into this block, check to
// see if it has a fall-through into its successor.
- bool CurFallsThru = CanFallThrough(MBB, CurUnAnalyzable, CurTBB, CurFBB,
+ bool CurFallsThru = CanFallThrough(MBB, CurUnAnalyzable, CurTBB, CurFBB,
CurCond);
if (!MBB->isLandingPad()) {
@@ -1150,7 +1166,7 @@
&& (!CurFallsThru || MBB->getNumber() >= PredBB->getNumber())) {
// If the current block doesn't fall through, just move it.
// If the current block can fall through and does not end with a
- // conditional branch, we need to append an unconditional jump to
+ // conditional branch, we need to append an unconditional jump to
// the (current) next block. To avoid a possible compile-time
// infinite loop, move blocks only backward in this case.
// Also, if there are already 2 branches here, we cannot add a third;
@@ -1169,7 +1185,7 @@
}
}
}
-
+
if (!CurFallsThru) {
// Check all successors to see if we can move this block before it.
for (MachineBasicBlock::succ_iterator SI = MBB->succ_begin(),
@@ -1178,7 +1194,7 @@
MachineBasicBlock *SuccBB = *SI;
MachineFunction::iterator SuccPrev = SuccBB; --SuccPrev;
std::vector<MachineOperand> SuccPrevCond;
-
+
// If this block doesn't already fall-through to that successor, and if
// the succ doesn't already have a block that can fall through into it,
// and if the successor isn't an EH destination, we can arrange for the
@@ -1190,7 +1206,7 @@
return OptimizeBlock(MBB);
}
}
-
+
// Okay, there is no really great place to put this block. If, however,
// the block before this one would be a fall-through if this block were
// removed, move this block to the end of the function.
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