diff options
| -rw-r--r-- | lib/Transforms/Utils/CriticalEdge.cpp | 14 |
1 files changed, 12 insertions, 2 deletions
diff --git a/lib/Transforms/Utils/CriticalEdge.cpp b/lib/Transforms/Utils/CriticalEdge.cpp index 07a3a542e5..35eac3f34d 100644 --- a/lib/Transforms/Utils/CriticalEdge.cpp +++ b/lib/Transforms/Utils/CriticalEdge.cpp @@ -7,6 +7,7 @@ #include "llvm/Transforms/Utils/Local.h" #include "llvm/iTerminators.h" +#include "llvm/iPHINode.h" #include "llvm/Analysis/Dominators.h" #include "llvm/Support/CFG.h" @@ -38,9 +39,9 @@ void SplitCriticalEdge(TerminatorInst *TI, unsigned SuccNum, Pass *P) { // Create a new basic block, linking it into the CFG. BasicBlock *NewBB = new BasicBlock(TIBB->getName()+"_crit_edge"); - + BasicBlock *DestBB = TI->getSuccessor(SuccNum); // Create our unconditional branch... - BranchInst *BI = new BranchInst(TI->getSuccessor(SuccNum)); + BranchInst *BI = new BranchInst(DestBB); NewBB->getInstList().push_back(BI); // Branch to the new block, breaking the edge... @@ -50,6 +51,15 @@ void SplitCriticalEdge(TerminatorInst *TI, unsigned SuccNum, Pass *P) { Function &F = *TIBB->getParent(); F.getBasicBlockList().insert(TIBB->getNext(), NewBB); + // If there are any PHI nodes in DestBB, we need to update them so that they + // merge incoming values from NewBB instead of from TIBB. + // + for (BasicBlock::iterator I = DestBB->begin(); + PHINode *PN = dyn_cast<PHINode>(&*I); ++I) { + // We no longer enter through TIBB, now we come in through NewBB. + PN->replaceUsesOfWith(TIBB, NewBB); + } + // Now if we have a pass object, update analysis information. Currently we // update DominatorSet and DominatorTree information if it's available. // |