diff options
| -rw-r--r-- | lib/Transforms/Utils/PromoteMemoryToRegister.cpp | 21 |
1 files changed, 17 insertions, 4 deletions
diff --git a/lib/Transforms/Utils/PromoteMemoryToRegister.cpp b/lib/Transforms/Utils/PromoteMemoryToRegister.cpp index ec249fc..d828f04 100644 --- a/lib/Transforms/Utils/PromoteMemoryToRegister.cpp +++ b/lib/Transforms/Utils/PromoteMemoryToRegister.cpp @@ -24,6 +24,7 @@ #include "llvm/Function.h" #include "llvm/Constant.h" #include "llvm/Type.h" +#include "llvm/Support/CFG.h" #include "Support/StringExtras.h" /// isAllocaPromotable - Return true if this alloca is legal for promotion. @@ -187,11 +188,20 @@ bool PromoteMem2Reg::QueuePhiNode(BasicBlock *BB, unsigned AllocaNo) { if (BBPNs[AllocaNo]) return false; // Create a PhiNode using the dereferenced type... and add the phi-node to the - // BasicBlock + // BasicBlock. PHINode *PN = new PHINode(Allocas[AllocaNo]->getAllocatedType(), Allocas[AllocaNo]->getName() + "." + utostr(VersionNumbers[AllocaNo]++), BB->begin()); + + // Add null incoming values for all predecessors. This ensures that if one of + // the predecessors is not found in the depth-first traversal of the CFG (ie, + // because it is an unreachable predecessor), that all PHI nodes will have the + // correct number of entries for their predecessors. + Value *NullVal = Constant::getNullValue(PN->getType()); + for (pred_iterator PI = pred_begin(BB), PE = pred_end(BB); PI != PE; ++PI) + PN->addIncoming(NullVal, *PI); + BBPNs[AllocaNo] = PN; PhiNodes[AllocaNo].push_back(BB); return true; @@ -205,9 +215,12 @@ void PromoteMem2Reg::RenamePass(BasicBlock *BB, BasicBlock *Pred, std::vector<PHINode *> &BBPNs = NewPhiNodes[BB]; for (unsigned k = 0; k != BBPNs.size(); ++k) if (PHINode *PN = BBPNs[k]) { - // at this point we can assume that the array has phi nodes.. let's add - // the incoming data - PN->addIncoming(IncomingVals[k], Pred); + int BBI = PN->getBasicBlockIndex(Pred); + assert(BBI >= 0 && "Predecessor not in basic block yet!"); + + // At this point we can assume that the array has phi nodes.. let's update + // the incoming data. + PN->setIncomingValue(BBI, IncomingVals[k]); // also note that the active variable IS designated by the phi node IncomingVals[k] = PN; |