diff options
| -rw-r--r-- | llvm/lib/Transforms/Scalar/Reassociate.cpp | 9 | ||||
| -rw-r--r-- | llvm/test/Transforms/Reassociate/invalid-iterator.ll | 30 |
2 files changed, 39 insertions, 0 deletions
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<Instruction>(V)) { if (InvokeInst *II = dyn_cast<InvokeInst>(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<Value*, 8> Ops(I->op_begin(), I->op_end()); // Erase the dead instruction. ValueRankMap.erase(I); diff --git a/llvm/test/Transforms/Reassociate/invalid-iterator.ll b/llvm/test/Transforms/Reassociate/invalid-iterator.ll new file mode 100644 index 00000000000..14211d1ede6 --- /dev/null +++ b/llvm/test/Transforms/Reassociate/invalid-iterator.ll @@ -0,0 +1,30 @@ +; RUN: opt < %s -reassociate -die -S | FileCheck %s + +; PR28367 +; Check to make sure %sub2 isn't moved from for.body. Doing so would invalidate +; the iterator. + +; CHECK-LABEL: @fn1 +; CHECK: for.body: +; CHECK-NEXT: %sub2 = sub nsw i32 0, %d.0 +; CHECK-NEXT: store i32 %sub2, i32* %ptr, align 4 +define void @fn1(i32 %a, i1 %c, i32* %ptr) { +entry: + br label %for.cond + +for.cond: + %d.0 = phi i32 [ 1, %entry ], [ 2, %for.body ] + br i1 %c, label %for.end, label %for.body + +for.body: + %sub1 = sub i32 %a, %d.0 + %dead1 = add i32 %sub1, 1 + %dead2 = mul i32 %dead1, 3 + %dead3 = mul i32 %dead2, %sub1 + %sub2 = sub nsw i32 0, %d.0 + store i32 %sub2, i32* %ptr, align 4 + br label %for.cond + +for.end: + ret void +} |
