Make method private. Keep coding standard.

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

View File

@ -34,13 +34,9 @@ namespace {
} }
// Possibly eliminate loop L if it is dead. // 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, virtual void getAnalysisUsage(AnalysisUsage &AU) const {
SmallVector<BasicBlock*, 4>& exitBlocks,
bool &Changed, BasicBlock *Preheader);
virtual void getAnalysisUsage(AnalysisUsage& AU) const {
AU.addRequired<DominatorTree>(); AU.addRequired<DominatorTree>();
AU.addRequired<LoopInfo>(); AU.addRequired<LoopInfo>();
AU.addRequired<ScalarEvolution>(); AU.addRequired<ScalarEvolution>();
@ -53,6 +49,12 @@ namespace {
AU.addPreservedID(LoopSimplifyID); AU.addPreservedID(LoopSimplifyID);
AU.addPreservedID(LCSSAID); 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", INITIALIZE_PASS_END(LoopDeletion, "loop-deletion",
"Delete dead loops", false, false) "Delete dead loops", false, false)
Pass* llvm::createLoopDeletionPass() { Pass *llvm::createLoopDeletionPass() {
return new LoopDeletion(); 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 /// checked for unique exit and exiting blocks, and that the code is in LCSSA
/// form. /// form.
bool LoopDeletion::IsLoopDead(Loop* L, bool LoopDeletion::isLoopDead(Loop *L,
SmallVector<BasicBlock*, 4>& exitingBlocks, SmallVector<BasicBlock*, 4> &exitingBlocks,
SmallVector<BasicBlock*, 4>& exitBlocks, SmallVector<BasicBlock*, 4> &exitBlocks,
bool &Changed, BasicBlock *Preheader) { 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. // 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 // 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 // sufficient to guarantee that no loop-variant values are used outside
// of the loop. // of the loop.
BasicBlock::iterator BI = exitBlock->begin(); BasicBlock::iterator BI = exitBlock->begin();
while (PHINode* P = dyn_cast<PHINode>(BI)) { while (PHINode *P = dyn_cast<PHINode>(BI)) {
Value* incoming = P->getIncomingValueForBlock(exitingBlocks[0]); Value *incoming = P->getIncomingValueForBlock(exitingBlocks[0]);
// Make sure all exiting blocks produce the same incoming value for the exit // Make sure all exiting blocks produce the same incoming value for the exit
// block. If there are different incoming values for different exiting // block. If there are different incoming values for different exiting
// blocks, then it is impossible to statically determine which value should // blocks, then it is impossible to statically determine which value should
// be used. // 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])) if (incoming != P->getIncomingValueForBlock(exitingBlocks[i]))
return false; return false;
} }
if (Instruction* I = dyn_cast<Instruction>(incoming)) if (Instruction *I = dyn_cast<Instruction>(incoming))
if (!L->makeLoopInvariant(I, Changed, Preheader->getTerminator())) if (!L->makeLoopInvariant(I, Changed, Preheader->getTerminator()))
return false; return false;
@ -127,10 +129,10 @@ bool LoopDeletion::IsLoopDead(Loop* L,
/// so could change the halting/non-halting nature of a program. /// so could change the halting/non-halting nature of a program.
/// NOTE: This entire process relies pretty heavily on LoopSimplify and LCSSA /// NOTE: This entire process relies pretty heavily on LoopSimplify and LCSSA
/// in order to make various safety checks work. /// 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 // We can only remove the loop if there is a preheader that we can
// branch from after removing it. // branch from after removing it.
BasicBlock* preheader = L->getLoopPreheader(); BasicBlock *preheader = L->getLoopPreheader();
if (!preheader) if (!preheader)
return false; return false;
@ -158,19 +160,19 @@ bool LoopDeletion::runOnLoop(Loop* L, LPPassManager& LPM) {
// Finally, we have to check that the loop really is dead. // Finally, we have to check that the loop really is dead.
bool Changed = false; bool Changed = false;
if (!IsLoopDead(L, exitingBlocks, exitBlocks, Changed, preheader)) if (!isLoopDead(L, exitingBlocks, exitBlocks, Changed, preheader))
return Changed; return Changed;
// Don't remove loops for which we can't solve the trip count. // 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. // 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); const SCEV *S = SE.getMaxBackedgeTakenCount(L);
if (isa<SCEVCouldNotCompute>(S)) if (isa<SCEVCouldNotCompute>(S))
return Changed; return Changed;
// Now that we know the removal is safe, remove the loop by changing the // 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. // 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 // 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 // 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); SE.forgetLoop(L);
// Connect the preheader directly to the exit block. // Connect the preheader directly to the exit block.
TerminatorInst* TI = preheader->getTerminator(); TerminatorInst *TI = preheader->getTerminator();
TI->replaceUsesOfWith(L->getHeader(), exitBlock); TI->replaceUsesOfWith(L->getHeader(), exitBlock);
// Rewrite phis in the exit block to get their inputs from // Rewrite phis in the exit block to get their inputs from
// the preheader instead of the exiting block. // the preheader instead of the exiting block.
BasicBlock* exitingBlock = exitingBlocks[0]; BasicBlock *exitingBlock = exitingBlocks[0];
BasicBlock::iterator BI = exitBlock->begin(); BasicBlock::iterator BI = exitBlock->begin();
while (PHINode* P = dyn_cast<PHINode>(BI)) { while (PHINode *P = dyn_cast<PHINode>(BI)) {
int j = P->getBasicBlockIndex(exitingBlock); int j = P->getBasicBlockIndex(exitingBlock);
assert(j >= 0 && "Can't find exiting block in exit block's phi node!"); assert(j >= 0 && "Can't find exiting block in exit block's phi node!");
P->setIncomingBlock(j, preheader); 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 // Update the dominator tree and remove the instructions and blocks that will
// be deleted from the reference counting scheme. // be deleted from the reference counting scheme.
DominatorTree& DT = getAnalysis<DominatorTree>(); DominatorTree &DT = getAnalysis<DominatorTree>();
SmallVector<DomTreeNode*, 8> ChildNodes; SmallVector<DomTreeNode*, 8> ChildNodes;
for (Loop::block_iterator LI = L->block_begin(), LE = L->block_end(); for (Loop::block_iterator LI = L->block_begin(), LE = L->block_end();
LI != LE; ++LI) { 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 // Finally, the blocks from loopinfo. This has to happen late because
// otherwise our loop iterators won't work. // otherwise our loop iterators won't work.
LoopInfo& loopInfo = getAnalysis<LoopInfo>(); LoopInfo &loopInfo = getAnalysis<LoopInfo>();
SmallPtrSet<BasicBlock*, 8> blocks; SmallPtrSet<BasicBlock*, 8> blocks;
blocks.insert(L->block_begin(), L->block_end()); blocks.insert(L->block_begin(), L->block_end());
for (SmallPtrSet<BasicBlock*,8>::iterator I = blocks.begin(), for (SmallPtrSet<BasicBlock*,8>::iterator I = blocks.begin(),