uint32_t nextNum = VN.getNextUnusedValueNumber();
unsigned num = VN.lookup_or_add(I);
+ if (BranchInst* BI = dyn_cast<BranchInst>(I)) {
+ localAvail[I->getParent()]->table.insert(std::make_pair(num, I));
+
+ if (!BI->isConditional() || isa<Constant>(BI->getCondition()))
+ return false;
+
+ Value* branchCond = BI->getCondition();
+ uint32_t condVN = VN.lookup_or_add(branchCond);
+
+ BasicBlock* trueSucc = BI->getSuccessor(0);
+ BasicBlock* falseSucc = BI->getSuccessor(1);
+
+ if (trueSucc->getSinglePredecessor())
+ localAvail[trueSucc]->table[condVN] = ConstantInt::getTrue();
+ if (falseSucc->getSinglePredecessor())
+ localAvail[falseSucc]->table[condVN] = ConstantInt::getFalse();
+
+ return false;
+
// Allocations are always uniquely numbered, so we can save time and memory
- // by fast failing them.
- if (isa<AllocationInst>(I) || isa<TerminatorInst>(I)) {
+ // by fast failing them.
+ } else if (isa<AllocationInst>(I) || isa<TerminatorInst>(I)) {
localAvail[I->getParent()]->table.insert(std::make_pair(num, I));
return false;
}
bool GVN::processBlock(BasicBlock* BB) {
- DomTreeNode* DTN = DT->getNode(BB);
// FIXME: Kill off toErase by doing erasing eagerly in a helper function (and
// incrementing BI before processing an instruction).
SmallVector<Instruction*, 8> toErase;
bool changed_function = false;
- if (DTN->getIDom())
- localAvail[BB] =
- new ValueNumberScope(localAvail[DTN->getIDom()->getBlock()]);
- else
- localAvail[BB] = new ValueNumberScope(0);
-
for (BasicBlock::iterator BI = BB->begin(), BE = BB->end();
BI != BE;) {
changed_function |= processInstruction(BI, toErase);
bool GVN::iterateOnFunction(Function &F) {
cleanupGlobalSets();
+ for (df_iterator<DomTreeNode*> DI = df_begin(DT->getRootNode()),
+ DE = df_end(DT->getRootNode()); DI != DE; ++DI) {
+ if (DI->getIDom())
+ localAvail[DI->getBlock()] =
+ new ValueNumberScope(localAvail[DI->getIDom()->getBlock()]);
+ else
+ localAvail[DI->getBlock()] = new ValueNumberScope(0);
+ }
+
// Top-down walk of the dominator tree
bool changed = false;
#if 0