- if (InVal) {
- // If all incoming values for the new PHI would be the same, just don't
- // make a new PHI. Instead, just remove the incoming values from the old
- // PHI.
- for (unsigned i = 0; i != NumPreds; ++i)
- PN->removeIncomingValue(Preds[i], false);
- } else {
- // If the values coming into the block are not the same, we need a PHI.
- // Create the new PHI node, insert it into NewBB at the end of the block
- PHINode *NewPHI =
- PHINode::Create(PN->getType(), PN->getName()+".ph", BI);
- if (AA) AA->copyValue(PN, NewPHI);
-
- // Move all of the PHI values for 'Preds' to the new PHI.
- for (unsigned i = 0; i != NumPreds; ++i) {
- Value *V = PN->removeIncomingValue(Preds[i], false);
- NewPHI->addIncoming(V, Preds[i]);
+ bool HasLoopExit = false;
+ UpdateAnalysisInformation(OrigBB, NewBB1, Preds, DT, LI, PreserveLCSSA,
+ HasLoopExit);
+
+ // Update the PHI nodes in OrigBB with the values coming from NewBB1.
+ UpdatePHINodes(OrigBB, NewBB1, Preds, BI1, HasLoopExit);
+
+ // Move the remaining edges from OrigBB to point to NewBB2.
+ SmallVector<BasicBlock*, 8> NewBB2Preds;
+ for (pred_iterator i = pred_begin(OrigBB), e = pred_end(OrigBB);
+ i != e; ) {
+ BasicBlock *Pred = *i++;
+ if (Pred == NewBB1) continue;
+ assert(!isa<IndirectBrInst>(Pred->getTerminator()) &&
+ "Cannot split an edge from an IndirectBrInst");
+ NewBB2Preds.push_back(Pred);
+ e = pred_end(OrigBB);
+ }
+
+ BasicBlock *NewBB2 = nullptr;
+ if (!NewBB2Preds.empty()) {
+ // Create another basic block for the rest of OrigBB's predecessors.
+ NewBB2 = BasicBlock::Create(OrigBB->getContext(),
+ OrigBB->getName() + Suffix2,
+ OrigBB->getParent(), OrigBB);
+ NewBBs.push_back(NewBB2);
+
+ // The new block unconditionally branches to the old block.
+ BranchInst *BI2 = BranchInst::Create(OrigBB, NewBB2);
+ BI2->setDebugLoc(OrigBB->getFirstNonPHI()->getDebugLoc());
+
+ // Move the remaining edges from OrigBB to point to NewBB2.
+ for (SmallVectorImpl<BasicBlock*>::iterator
+ i = NewBB2Preds.begin(), e = NewBB2Preds.end(); i != e; ++i)
+ (*i)->getTerminator()->replaceUsesOfWith(OrigBB, NewBB2);
+
+ // Update DominatorTree, LoopInfo, and LCCSA analysis information.
+ HasLoopExit = false;
+ UpdateAnalysisInformation(OrigBB, NewBB2, NewBB2Preds, DT, LI,
+ PreserveLCSSA, HasLoopExit);
+
+ // Update the PHI nodes in OrigBB with the values coming from NewBB2.
+ UpdatePHINodes(OrigBB, NewBB2, NewBB2Preds, BI2, HasLoopExit);
+ }
+
+ LandingPadInst *LPad = OrigBB->getLandingPadInst();
+ Instruction *Clone1 = LPad->clone();
+ Clone1->setName(Twine("lpad") + Suffix1);
+ NewBB1->getInstList().insert(NewBB1->getFirstInsertionPt(), Clone1);
+
+ if (NewBB2) {
+ Instruction *Clone2 = LPad->clone();
+ Clone2->setName(Twine("lpad") + Suffix2);
+ NewBB2->getInstList().insert(NewBB2->getFirstInsertionPt(), Clone2);
+
+ // Create a PHI node for the two cloned landingpad instructions.
+ PHINode *PN = PHINode::Create(LPad->getType(), 2, "lpad.phi", LPad);
+ PN->addIncoming(Clone1, NewBB1);
+ PN->addIncoming(Clone2, NewBB2);
+ LPad->replaceAllUsesWith(PN);
+ LPad->eraseFromParent();
+ } else {
+ // There is no second clone. Just replace the landing pad with the first
+ // clone.
+ LPad->replaceAllUsesWith(Clone1);
+ LPad->eraseFromParent();
+ }
+}
+
+/// FoldReturnIntoUncondBranch - This method duplicates the specified return
+/// instruction into a predecessor which ends in an unconditional branch. If
+/// the return instruction returns a value defined by a PHI, propagate the
+/// right value into the return. It returns the new return instruction in the
+/// predecessor.
+ReturnInst *llvm::FoldReturnIntoUncondBranch(ReturnInst *RI, BasicBlock *BB,
+ BasicBlock *Pred) {
+ Instruction *UncondBranch = Pred->getTerminator();
+ // Clone the return and add it to the end of the predecessor.
+ Instruction *NewRet = RI->clone();
+ Pred->getInstList().push_back(NewRet);
+
+ // If the return instruction returns a value, and if the value was a
+ // PHI node in "BB", propagate the right value into the return.
+ for (User::op_iterator i = NewRet->op_begin(), e = NewRet->op_end();
+ i != e; ++i) {
+ Value *V = *i;
+ Instruction *NewBC = nullptr;
+ if (BitCastInst *BCI = dyn_cast<BitCastInst>(V)) {
+ // Return value might be bitcasted. Clone and insert it before the
+ // return instruction.
+ V = BCI->getOperand(0);
+ NewBC = BCI->clone();
+ Pred->getInstList().insert(NewRet, NewBC);
+ *i = NewBC;
+ }
+ if (PHINode *PN = dyn_cast<PHINode>(V)) {
+ if (PN->getParent() == BB) {
+ if (NewBC)
+ NewBC->setOperand(0, PN->getIncomingValueForBlock(Pred));
+ else
+ *i = PN->getIncomingValueForBlock(Pred);