From cf3e8121a6c03518b2473250b277a4ce1326f5ed Mon Sep 17 00:00:00 2001 From: Chad Rosier Date: Wed, 17 Aug 2016 14:16:45 +0000 Subject: [Reassociate] Avoid iterator invalidation when negating value. Differential Revision: https://reviews.llvm.org/D23464 PR28367 llvm-svn: 278928 --- llvm/lib/Transforms/Scalar/Reassociate.cpp | 9 +++++++++ 1 file changed, 9 insertions(+) (limited to 'llvm/lib/Transforms/Scalar/Reassociate.cpp') diff --git a/llvm/lib/Transforms/Scalar/Reassociate.cpp b/llvm/lib/Transforms/Scalar/Reassociate.cpp index b930a8fb7e9..5b3e7c50e50 100644 --- a/llvm/lib/Transforms/Scalar/Reassociate.cpp +++ b/llvm/lib/Transforms/Scalar/Reassociate.cpp @@ -842,6 +842,13 @@ static Value *NegateValue(Value *V, Instruction *BI, if (TheNeg->getParent()->getParent() != BI->getParent()->getParent()) continue; + // Don't move the negate if it's in the block we're currently optimizing as + // this may invalidate our iterator. + // FIXME: We should find a more robust solution as we're missing local CSE + // opportunities because of this constraint. + if (TheNeg->getParent() == BI->getParent()) + continue; + BasicBlock::iterator InsertPt; if (Instruction *InstInput = dyn_cast(V)) { if (InvokeInst *II = dyn_cast(InstInput)) { @@ -1863,6 +1870,8 @@ void ReassociatePass::RecursivelyEraseDeadInsts( /// Zap the given instruction, adding interesting operands to the work list. void ReassociatePass::EraseInst(Instruction *I) { assert(isInstructionTriviallyDead(I) && "Trivially dead instructions only!"); + DEBUG(dbgs() << "Erasing dead inst: "; I->dump()); + SmallVector Ops(I->op_begin(), I->op_end()); // Erase the dead instruction. ValueRankMap.erase(I); -- cgit v1.2.3