//
// The LLVM Compiler Infrastructure
//
-// This file was developed by the LLVM research group and is distributed under
-// the University of Illinois Open Source License. See LICENSE.TXT for details.
+// This file is distributed under the University of Illinois Open Source
+// License. See LICENSE.TXT for details.
//
//===----------------------------------------------------------------------===//
//
#include "llvm/CodeGen/RegisterScavenging.h"
#include "llvm/Target/TargetInstrInfo.h"
#include "llvm/Target/TargetMachine.h"
-#include "llvm/Target/MRegisterInfo.h"
+#include "llvm/Target/TargetRegisterInfo.h"
#include "llvm/Support/CommandLine.h"
#include "llvm/Support/Debug.h"
#include "llvm/ADT/Statistic.h"
struct BranchFolder : public MachineFunctionPass {
static char ID;
- BranchFolder(bool defaultEnableTailMerge) :
+ explicit BranchFolder(bool defaultEnableTailMerge) :
MachineFunctionPass((intptr_t)&ID) {
switch (FlagEnableTailMerge) {
case cl::BOU_UNSET: EnableTailMerge = defaultEnableTailMerge; break;
MachineBasicBlock::iterator BBI1);
std::vector<std::pair<unsigned,MachineBasicBlock*> > MergePotentials;
- const MRegisterInfo *RegInfo;
+ const TargetRegisterInfo *RegInfo;
RegScavenger *RS;
// Branch optzn.
bool OptimizeBranches(MachineFunction &MF);
char BranchFolder::ID = 0;
}
-static bool CorrectExtraCFGEdges(MachineBasicBlock &MBB,
- MachineBasicBlock *DestA,
- MachineBasicBlock *DestB,
- bool isCond,
- MachineFunction::iterator FallThru);
-
FunctionPass *llvm::createBranchFoldingPass(bool DefaultEnableTailMerge) {
return new BranchFolder(DefaultEnableTailMerge); }
MachineBasicBlock *MBB = I, *TBB = 0, *FBB = 0;
std::vector<MachineOperand> Cond;
if (!TII->AnalyzeBranch(*MBB, TBB, FBB, Cond))
- EverMadeChange |= CorrectExtraCFGEdges(*MBB, TBB, FBB,
- !Cond.empty(), next(I));
+ EverMadeChange |= MBB->CorrectExtraCFGEdges(TBB, FBB, !Cond.empty());
}
RegInfo = MF.getTarget().getRegisterInfo();
for (unsigned op = 0, e = I->getNumOperands(); op != e; ++op) {
MachineOperand &Op = I->getOperand(op);
if (!Op.isJumpTableIndex()) continue;
- unsigned NewIdx = JTMapping[Op.getJumpTableIndex()];
- Op.setJumpTableIndex(NewIdx);
+ unsigned NewIdx = JTMapping[Op.getIndex()];
+ Op.setIndex(NewIdx);
// Remember that this JT is live.
JTIsLive[NewIdx] = true;
case MachineOperand::MO_Register: OperandHash = Op.getReg(); break;
case MachineOperand::MO_Immediate: OperandHash = Op.getImm(); break;
case MachineOperand::MO_MachineBasicBlock:
- OperandHash = Op.getMachineBasicBlock()->getNumber();
+ OperandHash = Op.getMBB()->getNumber();
break;
- case MachineOperand::MO_FrameIndex: OperandHash = Op.getFrameIndex(); break;
+ case MachineOperand::MO_FrameIndex:
case MachineOperand::MO_ConstantPoolIndex:
- OperandHash = Op.getConstantPoolIndex();
- break;
case MachineOperand::MO_JumpTableIndex:
- OperandHash = Op.getJumpTableIndex();
+ OperandHash = Op.getIndex();
break;
case MachineOperand::MO_GlobalAddress:
case MachineOperand::MO_ExternalSymbol:
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
+ // optimizations (like this one) may reorder and/or merge these
+ // directives.
+ I1->getOpcode() == TargetInstrInfo::INLINEASM) {
++I1; ++I2;
break;
}
/// EstimateRuntime - Make a rough estimate for how long it will take to run
/// the specified code.
static unsigned EstimateRuntime(MachineBasicBlock::iterator I,
- MachineBasicBlock::iterator E,
- const TargetInstrInfo *TII) {
+ MachineBasicBlock::iterator E) {
unsigned Time = 0;
for (; I != E; ++I) {
- const TargetInstrDescriptor &TID = TII->get(I->getOpcode());
- if (TID.Flags & M_CALL_FLAG)
+ const TargetInstrDesc &TID = I->getDesc();
+ if (TID.isCall())
Time += 10;
- else if (TID.Flags & (M_LOAD_FLAG|M_STORE_FLAG))
+ else if (TID.isSimpleLoad() || TID.mayStore())
Time += 2;
else
++Time;
MachineBasicBlock::iterator MBB1I,
MachineBasicBlock *MBB2,
MachineBasicBlock::iterator MBB2I,
- const TargetInstrInfo *TII,
MachineBasicBlock *PredBB) {
// If one block is the entry block, split the other one; we can't generate
// a branch to the entry block, as its label is not emitted.
// TODO: if we had some notion of which block was hotter, we could split
// the hot block, so it is the fall-through. Since we don't have profile info
// make a decision based on which will hurt most to split.
- unsigned MBB1Time = EstimateRuntime(MBB1->begin(), MBB1I, TII);
- unsigned MBB2Time = EstimateRuntime(MBB2->begin(), MBB2I, TII);
+ unsigned MBB1Time = EstimateRuntime(MBB1->begin(), MBB1I);
+ unsigned MBB2Time = EstimateRuntime(MBB2->begin(), MBB2I);
// If the MBB1 prefix takes "less time" to run than the MBB2 prefix, split the
// MBB1 block so it falls through. This will penalize the MBB2 path, but will
return true;
else if (p.second->getNumber() > q.second->getNumber())
return false;
- else
+ else {
+ // _GLIBCXX_DEBUG checks strict weak ordering, which involves comparing
+ // an object with itself.
+#ifndef _GLIBCXX_DEBUG
assert(0 && "Predecessor appears twice");
+#endif
+ return(false);
+ }
}
// See if any of the blocks in MergePotentials (which all have a common single
}
// Decide whether we want to split CurMBB or MBB2.
- if (ShouldSplitFirstBlock(CurMBB, BBI1, MBB2, BBI2, TII, PredBB)) {
+ if (ShouldSplitFirstBlock(CurMBB, BBI1, MBB2, BBI2, PredBB)) {
CurMBB = SplitMBBAt(*CurMBB, BBI1);
BBI1 = CurMBB->begin();
MergePotentials.back().second = CurMBB;
} else if (FBB) {
if (TBB!=IBB && FBB!=IBB) // cbr then ubr
continue;
- } else if (Cond.size() == 0) {
+ } else if (Cond.empty()) {
if (TBB!=IBB) // ubr
continue;
} else {
}
-/// CorrectExtraCFGEdges - Various pieces of code can cause excess edges in the
-/// CFG to be inserted. If we have proven that MBB can only branch to DestA and
-/// DestB, remove any other MBB successors from the CFG. DestA and DestB can
-/// be null.
-/// Besides DestA and DestB, retain other edges leading to LandingPads (currently
-/// there can be only one; we don't check or require that here).
-/// Note it is possible that DestA and/or DestB are LandingPads.
-static bool CorrectExtraCFGEdges(MachineBasicBlock &MBB,
- MachineBasicBlock *DestA,
- MachineBasicBlock *DestB,
- bool isCond,
- MachineFunction::iterator FallThru) {
- bool MadeChange = false;
- bool AddedFallThrough = false;
-
- // If this block ends with a conditional branch that falls through to its
- // successor, set DestB as the successor.
- if (isCond) {
- if (DestB == 0 && FallThru != MBB.getParent()->end()) {
- DestB = FallThru;
- AddedFallThrough = true;
- }
- } else {
- // If this is an unconditional branch with no explicit dest, it must just be
- // a fallthrough into DestB.
- if (DestA == 0 && FallThru != MBB.getParent()->end()) {
- DestA = FallThru;
- AddedFallThrough = true;
- }
- }
-
- MachineBasicBlock::succ_iterator SI = MBB.succ_begin();
- MachineBasicBlock *OrigDestA = DestA, *OrigDestB = DestB;
- while (SI != MBB.succ_end()) {
- if (*SI == DestA && DestA == DestB) {
- DestA = DestB = 0;
- ++SI;
- } else if (*SI == DestA) {
- DestA = 0;
- ++SI;
- } else if (*SI == DestB) {
- DestB = 0;
- ++SI;
- } else if ((*SI)->isLandingPad() &&
- *SI!=OrigDestA && *SI!=OrigDestB) {
- ++SI;
- } else {
- // Otherwise, this is a superfluous edge, remove it.
- MBB.removeSuccessor(SI);
- MadeChange = true;
- }
- }
- if (!AddedFallThrough) {
- assert(DestA == 0 && DestB == 0 &&
- "MachineCFG is missing edges!");
- } else if (isCond) {
- assert(DestA == 0 && "MachineCFG is missing edges!");
- }
- return MadeChange;
-}
-
-
/// CanFallThrough - Return true if the specified block (with the specified
/// branch condition) can implicitly transfer control to the block after it by
/// falling off the end of it. This should return false if it can reach the
/// a strict ordering, returning true for both (MBB1,MBB2) and (MBB2,MBB1) will
/// result in infinite loops.
static bool IsBetterFallthrough(MachineBasicBlock *MBB1,
- MachineBasicBlock *MBB2,
- const TargetInstrInfo &TII) {
+ 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;
+ if (MBB2->isSuccessor(MBB1)) return false;
MachineInstr *MBB1I = --MBB1->end();
MachineInstr *MBB2I = --MBB2->end();
- return TII.isCall(MBB2I->getOpcode()) && !TII.isCall(MBB1I->getOpcode());
+ return MBB2I->getDesc().isCall() && !MBB1I->getDesc().isCall();
}
/// OptimizeBlock - Analyze and optimize control flow related to the specified
TII->AnalyzeBranch(PrevBB, PriorTBB, PriorFBB, PriorCond);
if (!PriorUnAnalyzable) {
// If the CFG for the prior block has extra edges, remove them.
- MadeChange |= CorrectExtraCFGEdges(PrevBB, PriorTBB, PriorFBB,
- !PriorCond.empty(), MBB);
+ 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
// last. Only do the swap if one is clearly better to fall through than
// the other.
if (FallThrough == --MBB->getParent()->end() &&
- !IsBetterFallthrough(PriorTBB, MBB, *TII))
+ !IsBetterFallthrough(PriorTBB, MBB))
DoTransform = false;
// We don't want to do this transformation if we have control flow like:
bool CurUnAnalyzable = TII->AnalyzeBranch(*MBB, CurTBB, CurFBB, CurCond);
if (!CurUnAnalyzable) {
// If the CFG for the prior block has extra edges, remove them.
- MadeChange |= CorrectExtraCFGEdges(*MBB, CurTBB, CurFBB,
- !CurCond.empty(),
- ++MachineFunction::iterator(MBB));
+ MadeChange |= MBB->CorrectExtraCFGEdges(CurTBB, CurFBB, !CurCond.empty());
// 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:
// 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 &&
- TII->isBranch(MBB->begin()->getOpcode()) && CurTBB != MBB) {
+ 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
// then seeing if the block is empty.
}
// Iterate through all the predecessors, revectoring each in-turn.
- MachineBasicBlock::pred_iterator PI = MBB->pred_begin();
+ size_t PI = 0;
bool DidChange = false;
bool HasBranchToSelf = false;
- while (PI != MBB->pred_end()) {
- if (*PI == MBB) {
+ while(PI != MBB->pred_size()) {
+ MachineBasicBlock *PMBB = *(MBB->pred_begin() + PI);
+ if (PMBB == MBB) {
// If this block has an uncond branch to itself, leave it.
++PI;
HasBranchToSelf = true;
} else {
DidChange = true;
- (*PI)->ReplaceUsesOfBlockWith(MBB, CurTBB);
+ PMBB->ReplaceUsesOfBlockWith(MBB, CurTBB);
}
}
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