[Statepoint Lowering] Update misleading comments about chains
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@353800 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/lib/CodeGen/SelectionDAG/StatepointLowering.cpp b/lib/CodeGen/SelectionDAG/StatepointLowering.cpp
index a155537..6c72a9c 100644
--- a/lib/CodeGen/SelectionDAG/StatepointLowering.cpp
+++ b/lib/CodeGen/SelectionDAG/StatepointLowering.cpp
@@ -366,10 +366,6 @@
// We use TargetFrameIndex so that isel will not select it into LEA
Loc = Builder.DAG.getTargetFrameIndex(Index, Builder.getFrameIndexTy());
- // TODO: We can create TokenFactor node instead of
- // chaining stores one after another, this may allow
- // a bit more optimal scheduling for them
-
#ifndef NDEBUG
// Right now we always allocate spill slots that are of the same
// size as the value we're about to spill (the size of spillee can
@@ -398,6 +394,9 @@
static void lowerIncomingStatepointValue(SDValue Incoming, bool LiveInOnly,
SmallVectorImpl<SDValue> &Ops,
SelectionDAGBuilder &Builder) {
+ // Note: We know all of these spills are independent, but don't bother to
+ // exploit that chain wise. DAGCombine will happily do so as needed, so
+ // doing it here would be a small compile time win at most.
SDValue Chain = Builder.getRoot();
if (ConstantSDNode *C = dyn_cast<ConstantSDNode>(Incoming)) {
@@ -984,11 +983,11 @@
}
SDValue SpillSlot =
- DAG.getTargetFrameIndex(*DerivedPtrLocation, getFrameIndexTy());
+ DAG.getTargetFrameIndex(*DerivedPtrLocation, getFrameIndexTy());
- // Be conservative: flush all pending loads
- // TODO: Probably we can be less restrictive on this,
- // it may allow more scheduling opportunities.
+ // Note: We know all of these reloads are independent, but don't bother to
+ // exploit that chain wise. DAGCombine will happily do so as needed, so
+ // doing it here would be a small compile time win at most.
SDValue Chain = getRoot();
SDValue SpillLoad =
@@ -998,7 +997,6 @@
MachinePointerInfo::getFixedStack(DAG.getMachineFunction(),
*DerivedPtrLocation));
- // Again, be conservative, don't emit pending loads
DAG.setRoot(SpillLoad.getValue(1));
assert(SpillLoad.getNode());
