Commit d1f849a2 authored by Florian Hahn's avatar Florian Hahn
Browse files

[LV] Hoist code to mark conditional assumes as dead to caller (NFC). 

This is a follow-up suggested in D73423. It is sufficient to just add
the conditional assumes to DeadInstructions once.
parent 6d614a82

llvm/lib/Transforms/Vectorize/LoopVectorize.cpp

+7 −7
Original line number Diff line number Diff line
@@ -7130,6 +7130,13 @@ void LoopVectorizationPlanner::buildVPlansWithVPRecipes(unsigned MinVF, 
  SmallPtrSet<Instruction *, 4> DeadInstructions;

  collectTriviallyDeadInstructions(DeadInstructions);



  // Add assume instructions we need to drop to DeadInstructions, to prevent

  // them from being added to the VPlan.

  // TODO: We only need to drop assumes in blocks that get flattend. If the

  // control flow is preserved, we should keep them.

  auto &ConditionalAssumes = Legal->getConditionalAssumes();

  DeadInstructions.insert(ConditionalAssumes.begin(), ConditionalAssumes.end());



  DenseMap<Instruction *, Instruction *> &SinkAfter = Legal->getSinkAfter();

  // Dead instructions do not need sinking. Remove them from SinkAfter.

  for (Instruction *I : DeadInstructions)
@@ -7192,13 +7199,6 @@ VPlanPtr LoopVectorizationPlanner::buildVPlanWithVPRecipes( 
  // visit each basic block after having visited its predecessor basic blocks.

  // ---------------------------------------------------------------------------



  // Add assume instructions we need to drop to DeadInstructions, to prevent

  // them from being added to the VPlan.

  // TODO: We only need to drop assumes in blocks that get flattend. If the

  // control flow is preserved, we should keep them.

  auto &ConditionalAssumes = Legal->getConditionalAssumes();

  DeadInstructions.insert(ConditionalAssumes.begin(), ConditionalAssumes.end());



  // Create a dummy pre-entry VPBasicBlock to start building the VPlan.

  VPBasicBlock *VPBB = new VPBasicBlock("Pre-Entry");

  auto Plan = std::make_unique<VPlan>(VPBB);