[llvm-commits] [llvm] r86885 - in /llvm/trunk/lib/CodeGen: BranchFolding.cpp BranchFolding.h
Dan Gohman
gohman at apple.com
Wed Nov 11 13:57:02 PST 2009
Author: djg
Date: Wed Nov 11 15:57:02 2009
New Revision: 86885
URL: http://llvm.org/viewvc/llvm-project?rev=86885&view=rev
Log:
Promote MergePotentialsElt and SameTailElt to be regular classes
instead of typedefs for std::pair. This simplifies the type of
SameTails, which previously was std::vector<std::pair<std::vector<std::pair<unsigned, MachineBasicBlock *> >::iterator, MachineBasicBlock::iterator>
Modified:
llvm/trunk/lib/CodeGen/BranchFolding.cpp
llvm/trunk/lib/CodeGen/BranchFolding.h
Modified: llvm/trunk/lib/CodeGen/BranchFolding.cpp
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/CodeGen/BranchFolding.cpp?rev=86885&r1=86884&r2=86885&view=diff
==============================================================================
--- llvm/trunk/lib/CodeGen/BranchFolding.cpp (original)
+++ llvm/trunk/lib/CodeGen/BranchFolding.cpp Wed Nov 11 15:57:02 2009
@@ -429,24 +429,24 @@
TII->InsertBranch(*CurMBB, SuccBB, NULL, SmallVector<MachineOperand, 0>());
}
-static bool MergeCompare(const std::pair<unsigned,MachineBasicBlock*> &p,
- const std::pair<unsigned,MachineBasicBlock*> &q) {
- if (p.first < q.first)
- return true;
- else if (p.first > q.first)
- return false;
- else if (p.second->getNumber() < q.second->getNumber())
- return true;
- else if (p.second->getNumber() > q.second->getNumber())
- return false;
- else {
- // _GLIBCXX_DEBUG checks strict weak ordering, which involves comparing
- // an object with itself.
+bool
+BranchFolder::MergePotentialsElt::operator<(const MergePotentialsElt &o) const {
+ if (getHash() < o.getHash())
+ return true;
+ else if (getHash() > o.getHash())
+ return false;
+ else if (getBlock()->getNumber() < o.getBlock()->getNumber())
+ return true;
+ else if (getBlock()->getNumber() > o.getBlock()->getNumber())
+ return false;
+ else {
+ // _GLIBCXX_DEBUG checks strict weak ordering, which involves comparing
+ // an object with itself.
#ifndef _GLIBCXX_DEBUG
- llvm_unreachable("Predecessor appears twice");
+ llvm_unreachable("Predecessor appears twice");
#endif
- return false;
- }
+ return false;
+ }
}
/// CountTerminators - Count the number of terminators in the given
@@ -537,22 +537,23 @@
MPIterator HighestMPIter = prior(MergePotentials.end());
for (MPIterator CurMPIter = prior(MergePotentials.end()),
B = MergePotentials.begin();
- CurMPIter!=B && CurMPIter->first == CurHash;
+ CurMPIter!=B && CurMPIter->getHash() == CurHash;
--CurMPIter) {
- for (MPIterator I = prior(CurMPIter); I->first == CurHash ; --I) {
+ for (MPIterator I = prior(CurMPIter); I->getHash() == CurHash ; --I) {
unsigned CommonTailLen;
- if (ProfitableToMerge(CurMPIter->second, I->second, minCommonTailLength,
+ if (ProfitableToMerge(CurMPIter->getBlock(), I->getBlock(),
+ minCommonTailLength,
CommonTailLen, TrialBBI1, TrialBBI2,
SuccBB, PredBB)) {
if (CommonTailLen > maxCommonTailLength) {
SameTails.clear();
maxCommonTailLength = CommonTailLen;
HighestMPIter = CurMPIter;
- SameTails.push_back(std::make_pair(CurMPIter, TrialBBI1));
+ SameTails.push_back(SameTailElt(CurMPIter, TrialBBI1));
}
if (HighestMPIter == CurMPIter &&
CommonTailLen == maxCommonTailLength)
- SameTails.push_back(std::make_pair(I, TrialBBI2));
+ SameTails.push_back(SameTailElt(I, TrialBBI2));
}
if (I == B)
break;
@@ -568,16 +569,16 @@
MachineBasicBlock* PredBB) {
MPIterator CurMPIter, B;
for (CurMPIter = prior(MergePotentials.end()), B = MergePotentials.begin();
- CurMPIter->first == CurHash;
+ CurMPIter->getHash() == CurHash;
--CurMPIter) {
// Put the unconditional branch back, if we need one.
- MachineBasicBlock *CurMBB = CurMPIter->second;
+ MachineBasicBlock *CurMBB = CurMPIter->getBlock();
if (SuccBB && CurMBB != PredBB)
FixTail(CurMBB, SuccBB, TII);
if (CurMPIter == B)
break;
}
- if (CurMPIter->first!=CurHash)
+ if (CurMPIter->getHash() != CurHash)
CurMPIter++;
MergePotentials.erase(CurMPIter, MergePotentials.end());
}
@@ -590,29 +591,30 @@
unsigned TimeEstimate = ~0U;
for (i=0, commonTailIndex=0; i<SameTails.size(); i++) {
// Use PredBB if possible; that doesn't require a new branch.
- if (SameTails[i].first->second == PredBB) {
+ if (SameTails[i].getBlock() == PredBB) {
commonTailIndex = i;
break;
}
// 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(),
- SameTails[i].second);
+ unsigned t = EstimateRuntime(SameTails[i].getBlock()->begin(),
+ SameTails[i].getTailStartPos());
if (t <= TimeEstimate) {
TimeEstimate = t;
commonTailIndex = i;
}
}
- MachineBasicBlock::iterator BBI = SameTails[commonTailIndex].second;
- MachineBasicBlock *MBB = SameTails[commonTailIndex].first->second;
+ MachineBasicBlock::iterator BBI =
+ SameTails[commonTailIndex].getTailStartPos();
+ MachineBasicBlock *MBB = SameTails[commonTailIndex].getBlock();
DEBUG(errs() << "\nSplitting BB#" << MBB->getNumber() << ", size "
<< maxCommonTailLength);
MachineBasicBlock *newMBB = SplitMBBAt(*MBB, BBI);
- SameTails[commonTailIndex].first->second = newMBB;
- SameTails[commonTailIndex].second = newMBB->begin();
+ SameTails[commonTailIndex].setBlock(newMBB);
+ SameTails[commonTailIndex].setTailStartPos(newMBB->begin());
// If we split PredBB, newMBB is the new predecessor.
if (PredBB == MBB)
@@ -641,22 +643,22 @@
// new branching and as such are very likely to be profitable.
if (SuccBB) {
if (SuccBB->pred_size() == MergePotentials.size() &&
- !MergePotentials[0].second->empty()) {
+ !MergePotentials[0].getBlock()->empty()) {
// If all the predecessors have at least one tail instruction in common,
// merging is very likely to be a win since it won't require an increase
// in static branches, and it will decrease the static instruction count.
bool AllPredsMatch = true;
MachineBasicBlock::iterator FirstNonTerm;
- unsigned MinNumTerms = CountTerminators(MergePotentials[0].second,
+ unsigned MinNumTerms = CountTerminators(MergePotentials[0].getBlock(),
FirstNonTerm);
- if (FirstNonTerm != MergePotentials[0].second->end()) {
+ if (FirstNonTerm != MergePotentials[0].getBlock()->end()) {
for (unsigned i = 1, e = MergePotentials.size(); i != e; ++i) {
MachineBasicBlock::iterator OtherFirstNonTerm;
- unsigned NumTerms = CountTerminators(MergePotentials[0].second,
+ unsigned NumTerms = CountTerminators(MergePotentials[0].getBlock(),
OtherFirstNonTerm);
if (NumTerms < MinNumTerms)
MinNumTerms = NumTerms;
- if (OtherFirstNonTerm == MergePotentials[i].second->end() ||
+ if (OtherFirstNonTerm == MergePotentials[i].getBlock()->end() ||
OtherFirstNonTerm->isIdenticalTo(FirstNonTerm)) {
AllPredsMatch = false;
break;
@@ -672,7 +674,7 @@
DEBUG(errs() << "\nTryTailMergeBlocks: ";
for (unsigned i = 0, e = MergePotentials.size(); i != e; ++i)
- errs() << "BB#" << MergePotentials[i].second->getNumber()
+ errs() << "BB#" << MergePotentials[i].getBlock()->getNumber()
<< (i == e-1 ? "" : ", ");
errs() << "\n";
if (SuccBB) {
@@ -688,11 +690,11 @@
// Sort by hash value so that blocks with identical end sequences sort
// together.
- std::stable_sort(MergePotentials.begin(), MergePotentials.end(),MergeCompare);
+ std::stable_sort(MergePotentials.begin(), MergePotentials.end());
// Walk through equivalence sets looking for actual exact matches.
while (MergePotentials.size() > 1) {
- unsigned CurHash = MergePotentials.back().first;
+ unsigned CurHash = MergePotentials.back().getHash();
// Build SameTails, identifying the set of blocks with this hash code
// and with the maximum number of instructions in common.
@@ -711,31 +713,30 @@
// block, which we can't jump to), we can treat all blocks with this same
// tail at once. Use PredBB if that is one of the possibilities, as that
// will not introduce any extra branches.
- MachineBasicBlock *EntryBB = MergePotentials.begin()->second->
- getParent()->begin();
- unsigned int commonTailIndex, i;
- for (commonTailIndex=SameTails.size(), i=0; i<SameTails.size(); i++) {
- MachineBasicBlock *MBB = SameTails[i].first->second;
+ MachineBasicBlock *EntryBB = MergePotentials.begin()->getBlock()->
+ getParent()->begin();
+ unsigned commonTailIndex = SameTails.size();
+ for (unsigned i=0; i<SameTails.size(); i++) {
+ MachineBasicBlock *MBB = SameTails[i].getBlock();
if (MBB == EntryBB)
continue;
if (MBB == PredBB) {
commonTailIndex = i;
break;
}
- if (MBB->begin() == SameTails[i].second)
+ if (MBB->begin() == SameTails[i].getTailStartPos())
commonTailIndex = i;
}
if (commonTailIndex == SameTails.size() ||
- (SameTails[commonTailIndex].first->second == PredBB &&
- SameTails[commonTailIndex].first->second->begin() !=
- SameTails[i].second)) {
+ (SameTails[commonTailIndex].getBlock() == PredBB &&
+ !SameTails[commonTailIndex].tailIsWholeBlock())) {
// None of the blocks consist entirely of the common tail.
// Split a block so that one does.
commonTailIndex = CreateCommonTailOnlyBlock(PredBB, maxCommonTailLength);
}
- MachineBasicBlock *MBB = SameTails[commonTailIndex].first->second;
+ MachineBasicBlock *MBB = SameTails[commonTailIndex].getBlock();
// MBB is common tail. Adjust all other BB's to jump to this one.
// Traversal must be forwards so erases work.
DEBUG(errs() << "\nUsing common tail in BB#" << MBB->getNumber()
@@ -743,12 +744,12 @@
for (unsigned int i=0, e = SameTails.size(); i != e; ++i) {
if (commonTailIndex == i)
continue;
- DEBUG(errs() << "BB#" << SameTails[i].first->second->getNumber()
+ DEBUG(errs() << "BB#" << SameTails[i].getBlock()->getNumber()
<< (i == e-1 ? "" : ", "));
// Hack the end off BB i, making it jump to BB commonTailIndex instead.
- ReplaceTailWithBranchTo(SameTails[i].second, MBB);
+ ReplaceTailWithBranchTo(SameTails[i].getTailStartPos(), MBB);
// BB i is no longer a predecessor of SuccBB; remove it from the worklist.
- MergePotentials.erase(SameTails[i].first);
+ MergePotentials.erase(SameTails[i].getMPIter());
}
DEBUG(errs() << "\n");
// We leave commonTailIndex in the worklist in case there are other blocks
@@ -768,7 +769,7 @@
MergePotentials.clear();
for (MachineFunction::iterator I = MF.begin(), E = MF.end(); I != E; ++I) {
if (I->succ_empty())
- MergePotentials.push_back(std::make_pair(HashEndOfMBB(I, 2U), I));
+ MergePotentials.push_back(MergePotentialsElt(HashEndOfMBB(I, 2U), I));
}
// See if we can do any tail merging on those.
@@ -854,7 +855,8 @@
// reinsert conditional branch only, for now
TII->InsertBranch(*PBB, (TBB == IBB) ? FBB : TBB, 0, NewCond);
}
- MergePotentials.push_back(std::make_pair(HashEndOfMBB(PBB, 1U), *P));
+ MergePotentials.push_back(MergePotentialsElt(HashEndOfMBB(PBB, 1U),
+ *P));
}
}
if (MergePotentials.size() >= 2)
@@ -863,8 +865,8 @@
// The 1 below can occur as a result of removing blocks in TryTailMergeBlocks.
PredBB = prior(I); // this may have been changed in TryTailMergeBlocks
if (MergePotentials.size() == 1 &&
- MergePotentials.begin()->second != PredBB)
- FixTail(MergePotentials.begin()->second, IBB, TII);
+ MergePotentials.begin()->getBlock() != PredBB)
+ FixTail(MergePotentials.begin()->getBlock(), IBB, TII);
}
}
return MadeChange;
Modified: llvm/trunk/lib/CodeGen/BranchFolding.h
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/CodeGen/BranchFolding.h?rev=86885&r1=86884&r2=86885&view=diff
==============================================================================
--- llvm/trunk/lib/CodeGen/BranchFolding.h (original)
+++ llvm/trunk/lib/CodeGen/BranchFolding.h Wed Nov 11 15:57:02 2009
@@ -30,11 +30,58 @@
const TargetRegisterInfo *tri,
MachineModuleInfo *mmi);
private:
- typedef std::pair<unsigned,MachineBasicBlock*> MergePotentialsElt;
+ class MergePotentialsElt {
+ unsigned Hash;
+ MachineBasicBlock *Block;
+ public:
+ MergePotentialsElt(unsigned h, MachineBasicBlock *b)
+ : Hash(h), Block(b) {}
+
+ unsigned getHash() const { return Hash; }
+ MachineBasicBlock *getBlock() const { return Block; }
+
+ void setBlock(MachineBasicBlock *MBB) {
+ Block = MBB;
+ }
+
+ bool operator<(const MergePotentialsElt &) const;
+ };
typedef std::vector<MergePotentialsElt>::iterator MPIterator;
std::vector<MergePotentialsElt> MergePotentials;
- typedef std::pair<MPIterator, MachineBasicBlock::iterator> SameTailElt;
+ class SameTailElt {
+ MPIterator MPIter;
+ MachineBasicBlock::iterator TailStartPos;
+ public:
+ SameTailElt(MPIterator mp, MachineBasicBlock::iterator tsp)
+ : MPIter(mp), TailStartPos(tsp) {}
+
+ MPIterator getMPIter() const {
+ return MPIter;
+ }
+ MergePotentialsElt &getMergePotentialsElt() const {
+ return *getMPIter();
+ }
+ MachineBasicBlock::iterator getTailStartPos() const {
+ return TailStartPos;
+ }
+ unsigned getHash() const {
+ return getMergePotentialsElt().getHash();
+ }
+ MachineBasicBlock *getBlock() const {
+ return getMergePotentialsElt().getBlock();
+ }
+ bool tailIsWholeBlock() const {
+ return TailStartPos == getBlock()->begin();
+ }
+
+ void setBlock(MachineBasicBlock *MBB) {
+ getMergePotentialsElt().setBlock(MBB);
+ }
+ void setTailStartPos(MachineBasicBlock::iterator Pos) {
+ TailStartPos = Pos;
+ }
+ };
std::vector<SameTailElt> SameTails;
bool EnableTailMerge;
More information about the llvm-commits
mailing list