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[LoopUnrollAndJam] Use Lazy strategy for DTU. 

We can also apply the earlier updates to the lazy DTU, instead of
applying them directly.

Reviewers: kuhar, brzycki, asbirlea, SjoerdMeijer

Reviewed By: brzycki, asbirlea, SjoerdMeijer

Differential Revision: https://reviews.llvm.org/D66918

llvm-svn: 370391
This commit is contained in:
Florian Hahn 2019-08-29 17:47:58 +00:00
parent 11802ccc9f
commit f9cdb98f40
1 changed files with 4 additions and 2 deletions
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6
llvm/lib/Transforms/Utils/LoopUnrollAndJam.cpp
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@ -517,6 +517,7 @@ LoopUnrollResult llvm::UnrollAndJamLoop(
movePHIs(AftBlocksFirst[It], AftBlocksFirst[0]);
}
DomTreeUpdater DTU(DT, DomTreeUpdater::UpdateStrategy::Lazy);
// Dominator Tree. Remove the old links between Fore, Sub and Aft, adding the
// new ones required.
if (Count != 1) {
@ -530,7 +531,7 @@ LoopUnrollResult llvm::UnrollAndJamLoop(
ForeBlocksLast.back(), SubLoopBlocksFirst[0]);
DTUpdates.emplace_back(DominatorTree::UpdateKind::Insert,
SubLoopBlocksLast.back(), AftBlocksFirst[0]);
DT->applyUpdates(DTUpdates);
DTU.applyUpdatesPermissive(DTUpdates);
}
// Merge adjacent basic blocks, if possible.
@ -538,7 +539,6 @@ LoopUnrollResult llvm::UnrollAndJamLoop(
MergeBlocks.insert(ForeBlocksLast.begin(), ForeBlocksLast.end());
MergeBlocks.insert(SubLoopBlocksLast.begin(), SubLoopBlocksLast.end());
MergeBlocks.insert(AftBlocksLast.begin(), AftBlocksLast.end());
DomTreeUpdater DTU(DT, DomTreeUpdater::UpdateStrategy::Eager);
while (!MergeBlocks.empty()) {
BasicBlock *BB = *MergeBlocks.begin();
BranchInst *Term = dyn_cast<BranchInst>(BB->getTerminator());
@ -555,6 +555,8 @@ LoopUnrollResult llvm::UnrollAndJamLoop(
} else
MergeBlocks.erase(BB);
}
// Apply updates to the DomTree.
DT = &DTU.getDomTree();
// At this point, the code is well formed. We now do a quick sweep over the
// inserted code, doing constant propagation and dead code elimination as we