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TransformUtils: Avoid getNodePtrUnchecked() in integer division, NFC

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Stop relying on `getNodePtrUnchecked()` being useful on invalid
iterators.  This function is documented to be for internal use only, and
the pointer type will eventually have to change to remove UB from
ilist_iterator.  Instead, check the iterator before it has been
invalidated.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@261497 91177308-0d34-0410-b5e6-96231b3b80d8
This commit is contained in:
Duncan P. N. Exon Smith 2016-02-21 20:14:29 +00:00
parent 14147eda61
commit d73d33fedf
1 changed files with 7 additions and 2 deletions
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9
lib/Transforms/Utils/IntegerDivision.cpp
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@ -390,6 +390,8 @@ bool llvm::expandRemainder(BinaryOperator *Rem) {
Value *Remainder = generateSignedRemainderCode(Rem->getOperand(0),
Rem->getOperand(1), Builder);
// Check whether this is the insert point while Rem is still valid.
bool IsInsertPoint = Rem->getIterator() == Builder.GetInsertPoint();
Rem->replaceAllUsesWith(Remainder);
Rem->dropAllReferences();
Rem->eraseFromParent();
@ -397,7 +399,7 @@ bool llvm::expandRemainder(BinaryOperator *Rem) {
// If we didn't actually generate an urem instruction, we're done
// This happens for example if the input were constant. In this case the
// Builder insertion point was unchanged
if (Rem == Builder.GetInsertPoint().getNodePtrUnchecked())
if (IsInsertPoint)
return true;
BinaryOperator *BO = dyn_cast<BinaryOperator>(Builder.GetInsertPoint());
@ -446,6 +448,9 @@ bool llvm::expandDivision(BinaryOperator *Div) {
// Lower the code to unsigned division, and reset Div to point to the udiv.
Value *Quotient = generateSignedDivisionCode(Div->getOperand(0),
Div->getOperand(1), Builder);
// Check whether this is the insert point while Div is still valid.
bool IsInsertPoint = Div->getIterator() == Builder.GetInsertPoint();
Div->replaceAllUsesWith(Quotient);
Div->dropAllReferences();
Div->eraseFromParent();
@ -453,7 +458,7 @@ bool llvm::expandDivision(BinaryOperator *Div) {
// If we didn't actually generate an udiv instruction, we're done
// This happens for example if the input were constant. In this case the
// Builder insertion point was unchanged
if (Div == Builder.GetInsertPoint().getNodePtrUnchecked())
if (IsInsertPoint)
return true;
BinaryOperator *BO = dyn_cast<BinaryOperator>(Builder.GetInsertPoint());