Fix heap-use-after-free bug in expandSDiv when the operands are

constants, as discovered by ASAN.

Patch by Mehdi Amini!



git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@221401 91177308-0d34-0410-b5e6-96231b3b80d8
This commit is contained in:
Michael Ilseman 2014-11-05 21:28:24 +00:00
parent 36c4749c19
commit 9f59bc4a0d

View File

@ -398,11 +398,13 @@ bool llvm::expandRemainder(BinaryOperator *Rem) {
Rem->dropAllReferences();
Rem->eraseFromParent();
// If we didn't actually generate a udiv instruction, we're done
BinaryOperator *BO = dyn_cast<BinaryOperator>(Builder.GetInsertPoint());
if (!BO || BO->getOpcode() != Instruction::URem)
// 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())
return true;
BinaryOperator *BO = dyn_cast<BinaryOperator>(Builder.GetInsertPoint());
Rem = BO;
}
@ -456,11 +458,13 @@ bool llvm::expandDivision(BinaryOperator *Div) {
Div->dropAllReferences();
Div->eraseFromParent();
// If we didn't actually generate a udiv instruction, we're done
BinaryOperator *BO = dyn_cast<BinaryOperator>(Builder.GetInsertPoint());
if (!BO || BO->getOpcode() != Instruction::UDiv)
// 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())
return true;
BinaryOperator *BO = dyn_cast<BinaryOperator>(Builder.GetInsertPoint());
Div = BO;
}