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An MBB which branches to an EH landing pad shouldn't be considered for tail merging.

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In SjLj EH, the jump to the landing pad is not done explicitly through a branch
statement. The EH landing pad is added as a successor to the throwing
BB. Because of that however, the branch folding pass could mistakenly think that
it could merge the throwing BB with another BB. This isn't safe to do.
<rdar://problem/10334833>


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@142891 91177308-0d34-0410-b5e6-96231b3b80d8
This commit is contained in:
Bill Wendling 2011-10-25 00:54:05 +00:00
parent fef5ff07c9
commit 86ed4089e3
1 changed files with 2 additions and 1 deletions
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3
lib/CodeGen/BranchFolding.cpp
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@ -913,7 +913,8 @@ bool BranchFolder::TailMergeBlocks(MachineFunction &MF) {
// reinsert conditional branch only, for now
TII->InsertBranch(*PBB, (TBB == IBB) ? FBB : TBB, 0, NewCond, dl);
}
MergePotentials.push_back(MergePotentialsElt(HashEndOfMBB(PBB), *P));
if (!PBB->getLandingPadSuccessor())
MergePotentials.push_back(MergePotentialsElt(HashEndOfMBB(PBB),*P));
}
}
// If this is a large problem, avoid visiting the same basic blocks