Commit cd0cff43 authored by Whitney Tsang's avatar Whitney Tsang
Browse files

[NFCI][LoopUnrollAndJam] Minor changes. 

Summary:
1. Add assertions.
2. Verify more analyses.
These changes are moved out of https://reviews.llvm.org/D73129 to
simplify that review.

Reviewer: dmgreen, jdoerfert, Meinersbur, kbarton, bmahjour, etiotto
Reviewed By: dmgreen
Subscribers: fhahn, hiraditya, zzheng, llvm-commits, prithayan, anhtuyen
Tag: LLVM
Differential Revision: https://reviews.llvm.org/D73204
parent 127d3abf

llvm/lib/Transforms/Scalar/LoopUnrollAndJamPass.cpp

+0 −1
Original line number Diff line number Diff line
@@ -450,7 +450,6 @@ static bool tryToUnrollAndJamLoop(Function &F, DominatorTree &DT, LoopInfo &LI, 
  internal::appendLoopsToWorklist(reverse(LI), Worklist);

  while (!Worklist.empty()) {

    Loop *L = Worklist.pop_back_val();

    formLCSSA(*L, DT, &LI, &SE);

    LoopUnrollResult Result =

        tryToUnrollAndJamLoop(L, DT, &LI, SE, TTI, AC, DI, ORE, OptLevel);

    if (Result != LoopUnrollResult::Unmodified)

llvm/lib/Transforms/Utils/LoopUnrollAndJam.cpp

+23 −17
Original line number Diff line number Diff line
@@ -284,8 +284,7 @@ LoopUnrollResult llvm::UnrollAndJamLoop( 


  // Move any instructions from fore phi operands from AftBlocks into Fore.

  moveHeaderPhiOperandsToForeBlocks(

      Header, LatchBlock, SubLoop->getLoopPreheader()->getTerminator(),

      AftBlocks);

      Header, LatchBlock, ForeBlocksLast[0]->getTerminator(), AftBlocks);



  // The current on-the-fly SSA update requires blocks to be processed in

  // reverse postorder so that LastValueMap contains the correct value at each
@@ -447,8 +446,8 @@ LoopUnrollResult llvm::UnrollAndJamLoop( 
  // Update ForeBlocks successors and phi nodes

  BranchInst *ForeTerm =

      cast<BranchInst>(ForeBlocksLast.back()->getTerminator());

  BasicBlock *Dest = SubLoopBlocksFirst[0];

  ForeTerm->setSuccessor(0, Dest);

  assert(ForeTerm->getNumSuccessors() == 1 && "Expecting one successor");

  ForeTerm->setSuccessor(0, SubLoopBlocksFirst[0]);



  if (CompletelyUnroll) {

    while (PHINode *Phi = dyn_cast<PHINode>(ForeBlocksFirst[0]->begin())) {
@@ -465,8 +464,8 @@ LoopUnrollResult llvm::UnrollAndJamLoop( 
    // Remap ForeBlock successors from previous iteration to this

    BranchInst *ForeTerm =

        cast<BranchInst>(ForeBlocksLast[It - 1]->getTerminator());

    BasicBlock *Dest = ForeBlocksFirst[It];

    ForeTerm->setSuccessor(0, Dest);

    assert(ForeTerm->getNumSuccessors() == 1 && "Expecting one successor");

    ForeTerm->setSuccessor(0, ForeBlocksFirst[It]);

  }



  // Subloop successors and phis
@@ -495,12 +494,14 @@ LoopUnrollResult llvm::UnrollAndJamLoop( 
  }



  // Aft blocks successors and phis

  BranchInst *Term = cast<BranchInst>(AftBlocksLast.back()->getTerminator());

  BranchInst *AftTerm = cast<BranchInst>(AftBlocksLast.back()->getTerminator());

  if (CompletelyUnroll) {

    BranchInst::Create(LoopExit, Term);

    Term->eraseFromParent();

    BranchInst::Create(LoopExit, AftTerm);

    AftTerm->eraseFromParent();

  } else {

    Term->setSuccessor(!ContinueOnTrue, ForeBlocksFirst[0]);

    AftTerm->setSuccessor(!ContinueOnTrue, ForeBlocksFirst[0]);

    assert(AftTerm->getSuccessor(ContinueOnTrue) == LoopExit &&

           "Expecting the ContinueOnTrue successor of AftTerm to be LoopExit");

  }

  updatePHIBlocks(AftBlocksFirst[0], SubLoopBlocksLast[0],

                  SubLoopBlocksLast.back());
@@ -568,21 +569,26 @@ LoopUnrollResult llvm::UnrollAndJamLoop( 
  NumCompletelyUnrolledAndJammed += CompletelyUnroll;

  ++NumUnrolledAndJammed;



  // Update LoopInfo if the loop is completely removed.

  if (CompletelyUnroll)

    LI->erase(L);



#ifndef NDEBUG

  // We shouldn't have done anything to break loop simplify form or LCSSA.

  Loop *OuterL = L->getParentLoop();

  Loop *OutestLoop = OuterL ? OuterL : (!CompletelyUnroll ? L : SubLoop);

  Loop *OutestLoop = SubLoop->getParentLoop()

                         ? SubLoop->getParentLoop()->getParentLoop()

                               ? SubLoop->getParentLoop()->getParentLoop()

                               : SubLoop->getParentLoop()

                         : SubLoop;

  assert(DT->verify());

  LI->verify(*DT);

  assert(OutestLoop->isRecursivelyLCSSAForm(*DT, *LI));

  if (!CompletelyUnroll)

    assert(L->isLoopSimplifyForm());

  assert(SubLoop->isLoopSimplifyForm());

  assert(DT->verify());

  SE->verify();

#endif



  // Update LoopInfo if the loop is completely removed.

  if (CompletelyUnroll)

    LI->erase(L);



  return CompletelyUnroll ? LoopUnrollResult::FullyUnrolled

                          : LoopUnrollResult::PartiallyUnrolled;

}