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[SimplifyCFG] Remove pointer from SmallPtrSet before deletion

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Summary:
Previously, `eraseFromParent()` calls `delete` which invalidates the value of the pointer. Copying the value of the pointer later is undefined behavior in C++11 and implementation-defined (which may cause a segfault on implementations having strict pointer safety) in C++14.

This patch removes the BasicBlock pointer from related SmallPtrSet before `delete` invalidates it in the SimplifyCFG pass.

Reviewers: kuhar, dmgreen, davide, trentxintong

Reviewed By: kuhar, dmgreen

Subscribers: llvm-commits

Differential Revision: https://reviews.llvm.org/D50717

llvm-svn: 339773
This commit is contained in:
Chijun Sima 2018-08-15 13:56:21 +00:00
parent ec11a04ab3
commit 514bfb5e93
1 changed files with 3 additions and 3 deletions
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6
lib/Transforms/Utils/SimplifyCFG.cpp
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@ -3861,9 +3861,9 @@ bool SimplifyCFGOpt::SimplifySingleResume(ResumeInst *RI) {
}
// The landingpad is now unreachable. Zap it.
BB->eraseFromParent();
if (LoopHeaders)
LoopHeaders->erase(BB);
BB->eraseFromParent();
return true;
}
@ -4083,9 +4083,9 @@ bool SimplifyCFGOpt::SimplifyReturn(ReturnInst *RI, IRBuilder<> &Builder) {
// If we eliminated all predecessors of the block, delete the block now.
if (pred_empty(BB)) {
// We know there are no successors, so just nuke the block.
BB->eraseFromParent();
if (LoopHeaders)
LoopHeaders->erase(BB);
BB->eraseFromParent();
}
return true;
@ -4245,9 +4245,9 @@ bool SimplifyCFGOpt::SimplifyUnreachable(UnreachableInst *UI) {
// If this block is now dead, remove it.
if (pred_empty(BB) && BB != &BB->getParent()->getEntryBlock()) {
// We know there are no successors, so just nuke the block.
BB->eraseFromParent();
if (LoopHeaders)
LoopHeaders->erase(BB);
BB->eraseFromParent();
return true;
}