Factor the ReachesChainWithoutSideEffects out of dag combiner into
a public SDOperand::reachesChainWithoutSideEffects method. No
functionality change.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@46050 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/lib/CodeGen/SelectionDAG/DAGCombiner.cpp b/lib/CodeGen/SelectionDAG/DAGCombiner.cpp
index 0bb11fa..09e0c3e 100644
--- a/lib/CodeGen/SelectionDAG/DAGCombiner.cpp
+++ b/lib/CodeGen/SelectionDAG/DAGCombiner.cpp
@@ -4122,33 +4122,6 @@
return SDOperand();
}
-/// ReachesChainWithoutSideEffects - Do a little local search to see if Src can
-/// reach Dest without any side effects like a store, or call. Non-volatile
-/// loads are ok though.
-static bool ReachesChainWithoutSideEffects(SDOperand Src, SDOperand Dest,
- unsigned Depth = 0) {
- if (Src == Dest) return true;
-
- // Don't search too deeply, we just want to be able to see through
- // TokenFactor's etc.
- if (Depth == 2) return false;
-
- // If this is a token factor, all inputs to the TF happen in parallel. If any
- // of the operands of the TF reach dest, then we can do the xform.
- if (Src.getOpcode() == ISD::TokenFactor) {
- for (unsigned i = 0, e = Src.getNumOperands(); i != e; ++i)
- if (ReachesChainWithoutSideEffects(Src.getOperand(i), Dest, Depth+1))
- return true;
- return false;
- }
-
- // Loads don't have side effects, look through them.
- if (LoadSDNode *Ld = dyn_cast<LoadSDNode>(Src)) {
- if (!Ld->isVolatile())
- return ReachesChainWithoutSideEffects(Ld->getChain(), Dest, Depth+1);
- }
- return false;
-}
SDOperand DAGCombiner::visitSTORE(SDNode *N) {
StoreSDNode *ST = cast<StoreSDNode>(N);
@@ -4283,7 +4256,7 @@
!ST->isVolatile() &&
// There can't be any side effects between the load and store, such as
// a call or store.
- ReachesChainWithoutSideEffects(Chain, SDOperand(Ld, 1))) {
+ Chain.reachesChainWithoutSideEffects(SDOperand(Ld, 1))) {
// The store is dead, remove it.
return Chain;
}