namespace {
struct LCSSA : public LoopPass {
static char ID; // Pass identification, replacement for typeid
- LCSSA() : LoopPass(&ID) {}
+ LCSSA() : LoopPass(ID) {
+ initializeLCSSAPass(*PassRegistry::getPassRegistry());
+ }
// Cached analysis information for the current function.
- LoopInfo *LI;
DominatorTree *DT;
std::vector<BasicBlock*> LoopBlocks;
PredIteratorCache PredCache;
///
virtual void getAnalysisUsage(AnalysisUsage &AU) const {
AU.setPreservesCFG();
- AU.addRequiredID(LoopSimplifyID);
+
+ AU.addRequired<DominatorTree>();
+ AU.addRequired<LoopInfo>();
AU.addPreservedID(LoopSimplifyID);
- AU.addRequiredTransitive<LoopInfo>();
- AU.addPreserved<LoopInfo>();
- AU.addRequiredTransitive<DominatorTree>();
AU.addPreserved<ScalarEvolution>();
- AU.addPreserved<DominatorTree>();
-
- // Request DominanceFrontier now, even though LCSSA does
- // not use it. This allows Pass Manager to schedule Dominance
- // Frontier early enough such that one LPPassManager can handle
- // multiple loop transformation passes.
- AU.addRequired<DominanceFrontier>();
- AU.addPreserved<DominanceFrontier>();
}
private:
bool ProcessInstruction(Instruction *Inst,
/// verifyAnalysis() - Verify loop nest.
virtual void verifyAnalysis() const {
// Check the special guarantees that LCSSA makes.
- assert(L->isLCSSAForm() && "LCSSA form not preserved!");
+ assert(L->isLCSSAForm(*DT) && "LCSSA form not preserved!");
}
/// inLoop - returns true if the given block is within the current loop
}
char LCSSA::ID = 0;
-static RegisterPass<LCSSA> X("lcssa", "Loop-Closed SSA Form Pass");
+INITIALIZE_PASS_BEGIN(LCSSA, "lcssa", "Loop-Closed SSA Form Pass", false, false)
+INITIALIZE_PASS_DEPENDENCY(DominatorTree)
+INITIALIZE_PASS_DEPENDENCY(LoopInfo)
+INITIALIZE_PASS_END(LCSSA, "lcssa", "Loop-Closed SSA Form Pass", false, false)
Pass *llvm::createLCSSAPass() { return new LCSSA(); }
-const PassInfo *const llvm::LCSSAID = &X;
+char &llvm::LCSSAID = LCSSA::ID;
/// BlockDominatesAnExit - Return true if the specified block dominates at least
bool LCSSA::runOnLoop(Loop *TheLoop, LPPassManager &LPM) {
L = TheLoop;
- LI = &LPM.getAnalysis<LoopInfo>();
DT = &getAnalysis<DominatorTree>();
// Get the set of exiting blocks.
}
}
- assert(L->isLCSSAForm());
+ assert(L->isLCSSAForm(*DT));
PredCache.clear();
return MadeChange;
for (Value::use_iterator UI = Inst->use_begin(), E = Inst->use_end();
UI != E; ++UI) {
- BasicBlock *UserBB = cast<Instruction>(*UI)->getParent();
- if (PHINode *PN = dyn_cast<PHINode>(*UI))
+ User *U = *UI;
+ BasicBlock *UserBB = cast<Instruction>(U)->getParent();
+ if (PHINode *PN = dyn_cast<PHINode>(U))
UserBB = PN->getIncomingBlock(UI);
if (InstBB != UserBB && !inLoop(UserBB))
UsesToRewrite.push_back(&UI.getUse());
}
-
+
// If there are no uses outside the loop, exit with no change.
if (UsesToRewrite.empty()) return false;
DomTreeNode *DomNode = DT->getNode(DomBB);
SSAUpdater SSAUpdate;
- SSAUpdate.Initialize(Inst);
+ SSAUpdate.Initialize(Inst->getType(), Inst->getName());
// Insert the LCSSA phi's into all of the exit blocks dominated by the
- // value., and add them to the Phi's map.
+ // value, and add them to the Phi's map.
for (SmallVectorImpl<BasicBlock*>::const_iterator BBI = ExitBlocks.begin(),
BBE = ExitBlocks.end(); BBI != BBE; ++BBI) {
BasicBlock *ExitBB = *BBI;
PN->reserveOperandSpace(PredCache.GetNumPreds(ExitBB));
// Add inputs from inside the loop for this PHI.
- for (BasicBlock **PI = PredCache.GetPreds(ExitBB); *PI; ++PI)
+ for (BasicBlock **PI = PredCache.GetPreds(ExitBB); *PI; ++PI) {
PN->addIncoming(Inst, *PI);
+
+ // If the exit block has a predecessor not within the loop, arrange for
+ // the incoming value use corresponding to that predecessor to be
+ // rewritten in terms of a different LCSSA PHI.
+ if (!inLoop(*PI))
+ UsesToRewrite.push_back(
+ &PN->getOperandUse(
+ PN->getOperandNumForIncomingValue(PN->getNumIncomingValues()-1)));
+ }
// Remember that this phi makes the value alive in this block.
SSAUpdate.AddAvailableValue(ExitBB, PN);