diff options
Diffstat (limited to 'lib')
| -rw-r--r-- | lib/Transforms/Scalar/GVNPRE.cpp | 47 |
1 files changed, 26 insertions, 21 deletions
diff --git a/lib/Transforms/Scalar/GVNPRE.cpp b/lib/Transforms/Scalar/GVNPRE.cpp index 67dbabd045..cd50192763 100644 --- a/lib/Transforms/Scalar/GVNPRE.cpp +++ b/lib/Transforms/Scalar/GVNPRE.cpp @@ -377,7 +377,7 @@ namespace { SmallPtrSet<Value*, 32>& currExps, SmallPtrSet<Value*, 32>& currTemps, std::set<BasicBlock*>& visited); - unsigned buildsets(Function& F); + void buildsets(Function& F); void insertion_pre(Value* e, BasicBlock* BB, std::map<BasicBlock*, Value*>& avail, @@ -895,7 +895,7 @@ unsigned GVNPRE::buildsets_anticin(BasicBlock* BB, /// buildsets - Phase 1 of the main algorithm. Construct the AVAIL_OUT /// and the ANTIC_IN sets. -unsigned GVNPRE::buildsets(Function& F) { +void GVNPRE::buildsets(Function& F) { std::map<BasicBlock*, SmallPtrSet<Value*, 32> > generatedExpressions; std::map<BasicBlock*, SmallPtrSet<PHINode*, 32> > generatedPhis; std::map<BasicBlock*, SmallPtrSet<Value*, 32> > generatedTemporaries; @@ -937,32 +937,42 @@ unsigned GVNPRE::buildsets(Function& F) { // Phase 1, Part 2: calculate ANTIC_IN std::set<BasicBlock*> visited; + SmallPtrSet<BasicBlock*, 4> block_changed; + for (Function::iterator FI = F.begin(), FE = F.end(); FI != FE; ++FI) + block_changed.insert(FI); bool changed = true; unsigned iterations = 0; + while (changed) { changed = false; SmallPtrSet<Value*, 32> anticOut; - // Top-down walk of the postdominator tree + // Postorder walk of the CFG for (po_iterator<BasicBlock*> BBI = po_begin(&F.getEntryBlock()), BBE = po_end(&F.getEntryBlock()); BBI != BBE; ++BBI) { BasicBlock* BB = *BBI; - if (BB == 0) - continue; - unsigned ret = buildsets_anticin(BB, anticOut,generatedExpressions[BB], - generatedTemporaries[BB], visited); + if (block_changed.count(BB) != 0) { + unsigned ret = buildsets_anticin(BB, anticOut,generatedExpressions[BB], + generatedTemporaries[BB], visited); - if (ret == 0) { - changed = true; - continue; - } else { - visited.insert(BB); - if (ret == 2) { - DOUT << "CHANGED: " << BB->getName() << "\n"; + if (ret == 0) { + changed = true; + continue; + } else { + visited.insert(BB); + + if (ret == 2) + for (pred_iterator PI = pred_begin(BB), PE = pred_end(BB); + PI != PE; ++PI) { + block_changed.insert(*PI); + } + else + block_changed.erase(BB); + + changed |= (ret == 2); } - changed |= (ret == 2); } } @@ -970,8 +980,6 @@ unsigned GVNPRE::buildsets(Function& F) { } DOUT << "ITERATIONS: " << iterations << "\n"; - - return 0; // No bail, no changes } /// insertion_pre - When a partial redundancy has been identified, eliminate it @@ -1173,10 +1181,7 @@ bool GVNPRE::runOnFunction(Function &F) { // This phase calculates the AVAIL_OUT and ANTIC_IN sets // NOTE: If full postdom information is no available, this will bail // early, performing GVN but not PRE - unsigned bail = buildsets(F); - //If a bail occurred, terminate early - if (bail != 0) - return (bail == 2); + buildsets(F); // Phase 2: Insert // This phase inserts values to make partially redundant values |