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some cleanups: remove dead arguments and eliminate ivars

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that are just passed to one function.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@123067 91177308-0d34-0410-b5e6-96231b3b80d8
This commit is contained in:
Chris Lattner 2011-01-08 17:48:33 +00:00
parent 012ca949af
commit 4aefc9bf1b
1 changed files with 36 additions and 55 deletions
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91
lib/Transforms/Scalar/LoopRotation.cpp
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@ -59,25 +59,18 @@ namespace {
// Helper functions
/// Do actual work
bool rotateLoop(Loop *L, LPPassManager &LPM);
/// Initialize local data
void initialize();
bool rotateLoop(Loop *L);
/// After loop rotation, loop pre-header has multiple sucessors.
/// Insert one forwarding basic block to ensure that loop pre-header
/// has only one successor.
void preserveCanonicalLoopForm(LPPassManager &LPM);
void preserveCanonicalLoopForm(Loop *L, BasicBlock *OrigHeader,
BasicBlock *OrigPreHeader,
BasicBlock *OrigLatch, BasicBlock *NewHeader,
BasicBlock *Exit);
private:
LoopInfo *LI;
Loop *L;
BasicBlock *OrigHeader;
BasicBlock *OrigPreHeader;
BasicBlock *OrigLatch;
BasicBlock *NewHeader;
BasicBlock *Exit;
LPPassManager *LPM_Ptr;
};
}
@ -90,44 +83,28 @@ INITIALIZE_PASS_END(LoopRotate, "loop-rotate", "Rotate Loops", false, false)
Pass *llvm::createLoopRotatePass() { return new LoopRotate(); }
/// Initialize local data
void LoopRotate::initialize() {
L = NULL;
OrigHeader = NULL;
OrigPreHeader = NULL;
NewHeader = NULL;
Exit = NULL;
}
/// Rotate Loop L as many times as possible. Return true if
/// the loop is rotated at least once.
bool LoopRotate::runOnLoop(Loop *Lp, LPPassManager &LPM) {
bool LoopRotate::runOnLoop(Loop *L, LPPassManager &LPM) {
LI = &getAnalysis<LoopInfo>();
initialize();
LPM_Ptr = &LPM;
// One loop can be rotated multiple times.
bool MadeChange = false;
while (rotateLoop(Lp,LPM)) {
while (rotateLoop(L))
MadeChange = true;
initialize();
}
return MadeChange;
}
/// Rotate loop LP. Return true if the loop is rotated.
bool LoopRotate::rotateLoop(Loop *Lp, LPPassManager &LPM) {
L = Lp;
OrigPreHeader = L->getLoopPreheader();
bool LoopRotate::rotateLoop(Loop *L) {
BasicBlock *OrigPreHeader = L->getLoopPreheader();
if (!OrigPreHeader) return false;
OrigLatch = L->getLoopLatch();
BasicBlock *OrigLatch = L->getLoopLatch();
if (!OrigLatch) return false;
OrigHeader = L->getHeader();
BasicBlock *OrigHeader = L->getHeader();
// If the loop has only one block then there is not much to rotate.
if (L->getBlocks().size() == 1)
@ -171,8 +148,8 @@ bool LoopRotate::rotateLoop(Loop *Lp, LPPassManager &LPM) {
// Find new Loop header. NewHeader is a Header's one and only successor
// that is inside loop. Header's other successor is outside the
// loop. Otherwise loop is not suitable for rotation.
Exit = BI->getSuccessor(0);
NewHeader = BI->getSuccessor(1);
BasicBlock *Exit = BI->getSuccessor(0);
BasicBlock *NewHeader = BI->getSuccessor(1);
if (L->contains(Exit))
std::swap(Exit, NewHeader);
assert(NewHeader && "Unable to determine new loop header");
@ -328,7 +305,8 @@ bool LoopRotate::rotateLoop(Loop *Lp, LPPassManager &LPM) {
// at this point, if we don't mind updating dominator info.
// Establish a new preheader, update dominators, etc.
preserveCanonicalLoopForm(LPM);
preserveCanonicalLoopForm(L, OrigHeader, OrigPreHeader, OrigLatch,
NewHeader, Exit);
++NumRotated;
return true;
@ -338,15 +316,18 @@ bool LoopRotate::rotateLoop(Loop *Lp, LPPassManager &LPM) {
/// After loop rotation, loop pre-header has multiple sucessors.
/// Insert one forwarding basic block to ensure that loop pre-header
/// has only one successor.
void LoopRotate::preserveCanonicalLoopForm(LPPassManager &LPM) {
void LoopRotate::preserveCanonicalLoopForm(Loop *L, BasicBlock *OrigHeader,
BasicBlock *OrigPreHeader,
BasicBlock *OrigLatch,
BasicBlock *NewHeader,
BasicBlock *Exit) {
// Right now original pre-header has two successors, new header and
// exit block. Insert new block between original pre-header and
// new header such that loop's new pre-header has only one successor.
BasicBlock *NewPreHeader = BasicBlock::Create(OrigHeader->getContext(),
"bb.nph",
OrigHeader->getParent(),
NewHeader);
BasicBlock *NewPreHeader =
BasicBlock::Create(OrigHeader->getContext(), "bb.nph",
OrigHeader->getParent(), NewHeader);
LoopInfo &LI = getAnalysis<LoopInfo>();
if (Loop *PL = LI.getLoopFor(OrigPreHeader))
PL->addBasicBlockToLoop(NewPreHeader, LI.getBase());
@ -431,19 +412,19 @@ void LoopRotate::preserveCanonicalLoopForm(LPPassManager &LPM) {
for (Loop::block_iterator BI = L->block_begin(), BE = L->block_end();
BI != BE; ++BI) {
BasicBlock *B = *BI;
if (DT->dominates(B, NewLatch)) {
DominanceFrontier::iterator BDFI = DF->find(B);
if (BDFI != DF->end()) {
DominanceFrontier::DomSetType &BSet = BDFI->second;
BSet.erase(NewLatch);
BSet.insert(L->getHeader());
BSet.insert(Exit);
} else {
DominanceFrontier::DomSetType BSet;
BSet.insert(L->getHeader());
BSet.insert(Exit);
DF->addBasicBlock(B, BSet);
}
if (!DT->dominates(B, NewLatch)) continue;
DominanceFrontier::iterator BDFI = DF->find(B);
if (BDFI != DF->end()) {
DominanceFrontier::DomSetType &BSet = BDFI->second;
BSet.erase(NewLatch);
BSet.insert(L->getHeader());
BSet.insert(Exit);
} else {
DominanceFrontier::DomSetType BSet;
BSet.insert(L->getHeader());
BSet.insert(Exit);
DF->addBasicBlock(B, BSet);
}
}
}