diff options
Diffstat (limited to 'llvm/lib/Transforms')
| -rw-r--r-- | llvm/lib/Transforms/Scalar/JumpThreading.cpp | 22 |
1 files changed, 12 insertions, 10 deletions
diff --git a/llvm/lib/Transforms/Scalar/JumpThreading.cpp b/llvm/lib/Transforms/Scalar/JumpThreading.cpp index eba1c816566..0b5d2713b1a 100644 --- a/llvm/lib/Transforms/Scalar/JumpThreading.cpp +++ b/llvm/lib/Transforms/Scalar/JumpThreading.cpp @@ -2009,6 +2009,14 @@ bool JumpThreadingPass::ThreadEdge(BasicBlock *BB, PredTerm->setSuccessor(i, NewBB); } + // Enqueue required DT updates. + DDT->applyUpdates({{DominatorTree::Insert, NewBB, SuccBB}, + {DominatorTree::Insert, PredBB, NewBB}, + {DominatorTree::Delete, PredBB, BB}}); + + // Apply all updates we queued with DDT and get the updated Dominator Tree. + DominatorTree *DT = &DDT->flush(); + // If there were values defined in BB that are used outside the block, then we // now have to update all uses of the value to use either the original value, // the cloned value, or some PHI derived value. This can require arbitrary @@ -2018,16 +2026,16 @@ bool JumpThreadingPass::ThreadEdge(BasicBlock *BB, for (Instruction &I : *BB) { SmallVector<Use*, 16> UsesToRename; - // Scan all uses of this instruction to see if it is used outside of its - // block, and if so, record them in UsesToRename. Also, skip phi operands - // from PredBB - we'll remove them anyway. + // Scan all uses of this instruction to see if their uses are no longer + // dominated by the previous def and if so, record them in UsesToRename. + // Also, skip phi operands from PredBB - we'll remove them anyway. for (Use &U : I.uses()) { Instruction *User = cast<Instruction>(U.getUser()); if (PHINode *UserPN = dyn_cast<PHINode>(User)) { if (UserPN->getIncomingBlock(U) == BB || UserPN->getIncomingBlock(U) == PredBB) continue; - } else if (User->getParent() == BB) + } else if (DT->dominates(&I, U)) continue; UsesToRename.push_back(&U); @@ -2046,12 +2054,6 @@ bool JumpThreadingPass::ThreadEdge(BasicBlock *BB, SSAUpdate.AddUse(VarNum, U); } - DDT->applyUpdates({{DominatorTree::Insert, NewBB, SuccBB}, - {DominatorTree::Insert, PredBB, NewBB}, - {DominatorTree::Delete, PredBB, BB}}); - - // Apply all updates we queued with DDT and get the updated Dominator Tree. - DominatorTree *DT = &DDT->flush(); SSAUpdate.RewriteAllUses(DT); // At this point, the IR is fully up to date and consistent. Do a quick scan |
