Commit Graph

6 Commits

Author SHA1 Message Date
Chijun Sima bd5d80d050 [Dominators] Assert if there is modification to DelBB while it is awaiting deletion
Summary:
Previously, passes use
```
DomTreeUpdater DTU(DT, DomTreeUpdater::UpdateStrategy::Lazy);
DTU.deleteBB(DelBB);
```
to delete a BasicBlock.
But passes which don't have the ability to update DomTree (e.g. tailcallelim, simplifyCFG) cannot recognize a DelBB awaiting deletion and will continue to process this DelBB.
This is a simple approach to notify devs of passes which may use DTU in the future to deal with deleted BasicBlocks under Lazy Strategy correctly.

Reviewers: kuhar, brzycki, dmgreen

Reviewed By: kuhar

Subscribers: llvm-commits

Differential Revision: https://reviews.llvm.org/D49731

llvm-svn: 337891
2018-07-25 06:18:33 +00:00
Erich Keane 3b6bcf6d67 [NFC] Silence Wparentheses warning in DomTreeUpdater, introduced by 336968
llvm-svn: 337001
2018-07-13 14:41:15 +00:00
Chijun Sima 00712cb749 [DomTreeUpdater] Ignore updates when both DT and PDT are nullptrs
Summary:
Previously, when both DT and PDT are nullptrs and the UpdateStrategy is Lazy, DomTreeUpdater still pends updates inside.
After this patch, DomTreeUpdater will ignore all updates from(`applyUpdates()/insertEdge*()/deleteEdge*()`) in this case. (call `delBB()` still pends BasicBlock deletion until a flush event according to the doc).
The behavior of DomTreeUpdater previously documented won't change after the patch.

Reviewers: dmgreen, davide, kuhar, brzycki, grosser

Reviewed By: kuhar

Subscribers: llvm-commits

Differential Revision: https://reviews.llvm.org/D48974

llvm-svn: 336968
2018-07-13 04:02:13 +00:00
Jakub Kuderski 5e3ab7a940 Reappl "[Dominators] Add the DomTreeUpdater class"
Summary:
This patch is the first in a series of patches related to the [[ http://lists.llvm.org/pipermail/llvm-dev/2018-June/123883.html | RFC - A new dominator tree updater for LLVM ]].

This patch introduces the DomTreeUpdater class, which provides a cleaner API to perform updates on available dominator trees (none, only DomTree, only PostDomTree, both) using different update strategies (eagerly or lazily) to simplify the updating process.

—Prior to the patch—

   - Directly calling update functions of DominatorTree updates the data structure eagerly while DeferredDominance does updates lazily.
   - DeferredDominance class cannot be used when a PostDominatorTree also needs to be updated.
   - Functions receiving DT/DDT need to branch a lot which is currently necessary.
   - Functions using both DomTree and PostDomTree need to call the update function separately on both trees.
   - People need to construct an additional DeferredDominance class to use functions only receiving DDT.

—After the patch—

Patch by Chijun Sima <simachijun@gmail.com>.

Reviewers: kuhar, brzycki, dmgreen, grosser, davide

Reviewed By: kuhar, brzycki

Author: NutshellySima

Subscribers: vsk, mgorny, llvm-commits

Differential Revision: https://reviews.llvm.org/D48383

llvm-svn: 336163
2018-07-03 02:06:23 +00:00
Jakub Kuderski 198f3b16dc Revert "[Dominators] Add the DomTreeUpdater class"
Temporary revert because of a failing test on some buildbots.

This reverts commit r336114.

llvm-svn: 336117
2018-07-02 16:10:49 +00:00
Jakub Kuderski e813a9b380 [Dominators] Add the DomTreeUpdater class
Summary:
This patch is the first in a series of patches related to the [[ http://lists.llvm.org/pipermail/llvm-dev/2018-June/123883.html | RFC - A new dominator tree updater for LLVM ]].

This patch introduces the DomTreeUpdater class, which provides a cleaner API to perform updates on available dominator trees (none, only DomTree, only PostDomTree, both) using different update strategies (eagerly or lazily) to simplify the updating process.

—Prior to the patch—

   - Directly calling update functions of DominatorTree updates the data structure eagerly while DeferredDominance does updates lazily.
   - DeferredDominance class cannot be used when a PostDominatorTree also needs to be updated.
   - Functions receiving DT/DDT need to branch a lot which is currently necessary.
   - Functions using both DomTree and PostDomTree need to call the update function separately on both trees.
   - People need to construct an additional DeferredDominance class to use functions only receiving DDT.

—After the patch—

Patch by Chijun Sima <simachijun@gmail.com>.

Reviewers: kuhar, brzycki, dmgreen, grosser, davide

Reviewed By: kuhar, brzycki

Subscribers: vsk, mgorny, llvm-commits

Author: NutshellySima

Differential Revision: https://reviews.llvm.org/D48383

llvm-svn: 336114
2018-07-02 15:37:41 +00:00