diff options
| -rw-r--r-- | llvm/lib/Target/X86/X86ISelDAGToDAG.cpp | 7 |
1 files changed, 5 insertions, 2 deletions
diff --git a/llvm/lib/Target/X86/X86ISelDAGToDAG.cpp b/llvm/lib/Target/X86/X86ISelDAGToDAG.cpp index a900a69ba71..21681f9c4d0 100644 --- a/llvm/lib/Target/X86/X86ISelDAGToDAG.cpp +++ b/llvm/lib/Target/X86/X86ISelDAGToDAG.cpp @@ -364,7 +364,9 @@ static void MoveBelowTokenFactor(SelectionDAG *CurDAG, SDValue Load, Store.getOperand(2), Store.getOperand(3)); } -/// isRMWLoad - Return true if N is a load that's part of RMW sub-DAG. +/// isRMWLoad - Return true if N is a load that's part of RMW sub-DAG. The +/// chain produced by the load must only be used by the store's chain operand, +/// otherwise this may produce a cycle in the DAG. /// static bool isRMWLoad(SDValue N, SDValue Chain, SDValue Address, SDValue &Load) { @@ -382,8 +384,9 @@ static bool isRMWLoad(SDValue N, SDValue Chain, SDValue Address, return false; if (N.hasOneUse() && + LD->hasNUsesOfValue(1, 1) && N.getOperand(1) == Address && - N.getNode()->isOperandOf(Chain.getNode())) { + LD->isOperandOf(Chain.getNode())) { Load = N; return true; } |
