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Make method private. Keep coding standard.

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git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@177348 91177308-0d34-0410-b5e6-96231b3b80d8
This commit is contained in:
Jakub Staszak 2013-03-18 23:31:30 +00:00
parent ee29c16890
commit 89c4dc6339
1 changed files with 28 additions and 26 deletions
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54
lib/Transforms/Scalar/LoopDeletion.cpp
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@ -34,13 +34,9 @@ namespace {
}
// Possibly eliminate loop L if it is dead.
bool runOnLoop(Loop* L, LPPassManager& LPM);
bool runOnLoop(Loop *L, LPPassManager &LPM);
bool IsLoopDead(Loop* L, SmallVector<BasicBlock*, 4>& exitingBlocks,
SmallVector<BasicBlock*, 4>& exitBlocks,
bool &Changed, BasicBlock *Preheader);
virtual void getAnalysisUsage(AnalysisUsage& AU) const {
virtual void getAnalysisUsage(AnalysisUsage &AU) const {
AU.addRequired<DominatorTree>();
AU.addRequired<LoopInfo>();
AU.addRequired<ScalarEvolution>();
@ -53,6 +49,12 @@ namespace {
AU.addPreservedID(LoopSimplifyID);
AU.addPreservedID(LCSSAID);
}
private:
bool isLoopDead(Loop *L, SmallVector<BasicBlock*, 4> &exitingBlocks,
SmallVector<BasicBlock*, 4> &exitBlocks,
bool &Changed, BasicBlock *Preheader);
};
}
@ -67,18 +69,18 @@ INITIALIZE_PASS_DEPENDENCY(LCSSA)
INITIALIZE_PASS_END(LoopDeletion, "loop-deletion",
"Delete dead loops", false, false)
Pass* llvm::createLoopDeletionPass() {
Pass *llvm::createLoopDeletionPass() {
return new LoopDeletion();
}
/// IsLoopDead - Determined if a loop is dead. This assumes that we've already
/// isLoopDead - Determined if a loop is dead. This assumes that we've already
/// checked for unique exit and exiting blocks, and that the code is in LCSSA
/// form.
bool LoopDeletion::IsLoopDead(Loop* L,
SmallVector<BasicBlock*, 4>& exitingBlocks,
SmallVector<BasicBlock*, 4>& exitBlocks,
bool LoopDeletion::isLoopDead(Loop *L,
SmallVector<BasicBlock*, 4> &exitingBlocks,
SmallVector<BasicBlock*, 4> &exitBlocks,
bool &Changed, BasicBlock *Preheader) {
BasicBlock* exitBlock = exitBlocks[0];
BasicBlock *exitBlock = exitBlocks[0];
// Make sure that all PHI entries coming from the loop are loop invariant.
// Because the code is in LCSSA form, any values used outside of the loop
@ -86,19 +88,19 @@ bool LoopDeletion::IsLoopDead(Loop* L,
// sufficient to guarantee that no loop-variant values are used outside
// of the loop.
BasicBlock::iterator BI = exitBlock->begin();
while (PHINode* P = dyn_cast<PHINode>(BI)) {
Value* incoming = P->getIncomingValueForBlock(exitingBlocks[0]);
while (PHINode *P = dyn_cast<PHINode>(BI)) {
Value *incoming = P->getIncomingValueForBlock(exitingBlocks[0]);
// Make sure all exiting blocks produce the same incoming value for the exit
// block. If there are different incoming values for different exiting
// blocks, then it is impossible to statically determine which value should
// be used.
for (unsigned i = 1; i < exitingBlocks.size(); ++i) {
for (unsigned i = 1, e = exitingBlocks.size(); i < e; ++i) {
if (incoming != P->getIncomingValueForBlock(exitingBlocks[i]))
return false;
}
if (Instruction* I = dyn_cast<Instruction>(incoming))
if (Instruction *I = dyn_cast<Instruction>(incoming))
if (!L->makeLoopInvariant(I, Changed, Preheader->getTerminator()))
return false;
@ -127,10 +129,10 @@ bool LoopDeletion::IsLoopDead(Loop* L,
/// so could change the halting/non-halting nature of a program.
/// NOTE: This entire process relies pretty heavily on LoopSimplify and LCSSA
/// in order to make various safety checks work.
bool LoopDeletion::runOnLoop(Loop* L, LPPassManager& LPM) {
bool LoopDeletion::runOnLoop(Loop *L, LPPassManager &LPM) {
// We can only remove the loop if there is a preheader that we can
// branch from after removing it.
BasicBlock* preheader = L->getLoopPreheader();
BasicBlock *preheader = L->getLoopPreheader();
if (!preheader)
return false;
@ -158,19 +160,19 @@ bool LoopDeletion::runOnLoop(Loop* L, LPPassManager& LPM) {
// Finally, we have to check that the loop really is dead.
bool Changed = false;
if (!IsLoopDead(L, exitingBlocks, exitBlocks, Changed, preheader))
if (!isLoopDead(L, exitingBlocks, exitBlocks, Changed, preheader))
return Changed;
// Don't remove loops for which we can't solve the trip count.
// They could be infinite, in which case we'd be changing program behavior.
ScalarEvolution& SE = getAnalysis<ScalarEvolution>();
ScalarEvolution &SE = getAnalysis<ScalarEvolution>();
const SCEV *S = SE.getMaxBackedgeTakenCount(L);
if (isa<SCEVCouldNotCompute>(S))
return Changed;
// Now that we know the removal is safe, remove the loop by changing the
// branch from the preheader to go to the single exit block.
BasicBlock* exitBlock = exitBlocks[0];
BasicBlock *exitBlock = exitBlocks[0];
// Because we're deleting a large chunk of code at once, the sequence in which
// we remove things is very important to avoid invalidation issues. Don't
@ -182,14 +184,14 @@ bool LoopDeletion::runOnLoop(Loop* L, LPPassManager& LPM) {
SE.forgetLoop(L);
// Connect the preheader directly to the exit block.
TerminatorInst* TI = preheader->getTerminator();
TerminatorInst *TI = preheader->getTerminator();
TI->replaceUsesOfWith(L->getHeader(), exitBlock);
// Rewrite phis in the exit block to get their inputs from
// the preheader instead of the exiting block.
BasicBlock* exitingBlock = exitingBlocks[0];
BasicBlock *exitingBlock = exitingBlocks[0];
BasicBlock::iterator BI = exitBlock->begin();
while (PHINode* P = dyn_cast<PHINode>(BI)) {
while (PHINode *P = dyn_cast<PHINode>(BI)) {
int j = P->getBasicBlockIndex(exitingBlock);
assert(j >= 0 && "Can't find exiting block in exit block's phi node!");
P->setIncomingBlock(j, preheader);
@ -200,7 +202,7 @@ bool LoopDeletion::runOnLoop(Loop* L, LPPassManager& LPM) {
// Update the dominator tree and remove the instructions and blocks that will
// be deleted from the reference counting scheme.
DominatorTree& DT = getAnalysis<DominatorTree>();
DominatorTree &DT = getAnalysis<DominatorTree>();
SmallVector<DomTreeNode*, 8> ChildNodes;
for (Loop::block_iterator LI = L->block_begin(), LE = L->block_end();
LI != LE; ++LI) {
@ -230,7 +232,7 @@ bool LoopDeletion::runOnLoop(Loop* L, LPPassManager& LPM) {
// Finally, the blocks from loopinfo. This has to happen late because
// otherwise our loop iterators won't work.
LoopInfo& loopInfo = getAnalysis<LoopInfo>();
LoopInfo &loopInfo = getAnalysis<LoopInfo>();
SmallPtrSet<BasicBlock*, 8> blocks;
blocks.insert(L->block_begin(), L->block_end());
for (SmallPtrSet<BasicBlock*,8>::iterator I = blocks.begin(),