diff options
author | Tobias Grosser <tobias@grosser.es> | 2017-05-29 06:12:18 +0000 |
---|---|---|
committer | Tobias Grosser <tobias@grosser.es> | 2017-05-29 06:12:18 +0000 |
commit | 8cf785f6b19cf7a3dac9cda4fd386a876c0f108d (patch) | |
tree | 098765bbd11574ff5a8fc2313a5059e076e14983 /llvm/lib/CodeGen/IfConversion.cpp | |
parent | 6aa9e9b41a578cc086684d76e70660dfb162d421 (diff) | |
download | llvm-8cf785f6b19cf7a3dac9cda4fd386a876c0f108d.zip llvm-8cf785f6b19cf7a3dac9cda4fd386a876c0f108d.tar.gz llvm-8cf785f6b19cf7a3dac9cda4fd386a876c0f108d.tar.bz2 |
Revert "[IfConversion] Keep the CFG updated incrementally in IfConvertTriangle"
The reverted change introdued assertions ala:
"MachineBasicBlock::succ_iterator
llvm::MachineBasicBlock::removeSuccessor(succ_iterator, bool): Assertion
`I != Successors.end() && "Not a current successor!"'
Mikael, the original committer, wrote me that he is working on a fix, but that
it likely will take some time to get this resolved. As this bug is one of the
last two issues that keep the AOSP buildbot from turning green, I revert the
original commit r302876.
I am looking forward to see this recommitted after the assertion has been
resolved.
llvm-svn: 304128
Diffstat (limited to 'llvm/lib/CodeGen/IfConversion.cpp')
-rw-r--r-- | llvm/lib/CodeGen/IfConversion.cpp | 27 |
1 files changed, 6 insertions, 21 deletions
diff --git a/llvm/lib/CodeGen/IfConversion.cpp b/llvm/lib/CodeGen/IfConversion.cpp index 8f3b6f9..1c33f3b 100644 --- a/llvm/lib/CodeGen/IfConversion.cpp +++ b/llvm/lib/CodeGen/IfConversion.cpp @@ -1588,32 +1588,22 @@ bool IfConverter::IfConvertTriangle(BBInfo &BBI, IfcvtKind Kind) { BBCvt = MBPI->getEdgeProbability(BBI.BB, &CvtMBB); } - // To be able to insert code freely at the end of BBI we sometimes remove - // the branch from BBI to NextMBB temporarily. Remember if this happened. - bool RemovedBranchToNextMBB = false; if (CvtMBB.pred_size() > 1) { BBI.NonPredSize -= TII->removeBranch(*BBI.BB); // Copy instructions in the true block, predicate them, and add them to // the entry block. CopyAndPredicateBlock(BBI, *CvtBBI, Cond, true); - // Keep the CFG updated. + // RemoveExtraEdges won't work if the block has an unanalyzable branch, so + // explicitly remove CvtBBI as a successor. BBI.BB->removeSuccessor(&CvtMBB, true); } else { // Predicate the 'true' block after removing its branch. CvtBBI->NonPredSize -= TII->removeBranch(CvtMBB); PredicateBlock(*CvtBBI, CvtMBB.end(), Cond); - // Remove the branch from the entry of the triangle to NextBB to be able to - // do the merge below. Keep the CFG updated, but remember we removed the - // branch since we do want to execute NextMBB, either by introducing a - // branch to it again, or merging it into the entry block. - // How it's handled is decided further down. - BBI.NonPredSize -= TII->removeBranch(*BBI.BB); - BBI.BB->removeSuccessor(&NextMBB, true); - RemovedBranchToNextMBB = true; - // Now merge the entry of the triangle with the true block. + BBI.NonPredSize -= TII->removeBranch(*BBI.BB); MergeBlocks(BBI, *CvtBBI, false); } @@ -1651,19 +1641,12 @@ bool IfConverter::IfConvertTriangle(BBInfo &BBI, IfcvtKind Kind) { // block. By not merging them, we make it possible to iteratively // ifcvt the blocks. if (!HasEarlyExit && - // We might have removed BBI from NextMBB's predecessor list above but - // we want it to be there, so consider that too. - (NextMBB.pred_size() == (RemovedBranchToNextMBB ? 0 : 1)) && - !NextBBI->HasFallThrough && + NextMBB.pred_size() == 1 && !NextBBI->HasFallThrough && !NextMBB.hasAddressTaken()) { - // We will merge NextBBI into BBI, and thus remove the current - // fallthrough from BBI into CvtBBI. - BBI.BB->removeSuccessor(&CvtMBB, true); MergeBlocks(BBI, *NextBBI); FalseBBDead = true; } else { InsertUncondBranch(*BBI.BB, NextMBB, TII); - BBI.BB->addSuccessor(&NextMBB); BBI.HasFallThrough = false; } // Mixed predicated and unpredicated code. This cannot be iteratively @@ -1671,6 +1654,8 @@ bool IfConverter::IfConvertTriangle(BBInfo &BBI, IfcvtKind Kind) { IterIfcvt = false; } + RemoveExtraEdges(BBI); + // Update block info. BB can be iteratively if-converted. if (!IterIfcvt) BBI.IsDone = true; |