Fix PR6497, a bug where we'd fold a load into an addc
node which has a flag. That flag in turn was used by an
already-selected adde which turned into an ADC32ri8 which
used a selected load which was chained to the load we
folded. This flag use caused us to form a cycle. Fix
this by not ignoring chains in IsLegalToFold even in
cases where the isel thinks it can.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@97791 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/lib/CodeGen/SelectionDAG/SelectionDAGISel.cpp b/lib/CodeGen/SelectionDAG/SelectionDAGISel.cpp
index b9ec4c4..f426fb1 100644
--- a/lib/CodeGen/SelectionDAG/SelectionDAGISel.cpp
+++ b/lib/CodeGen/SelectionDAG/SelectionDAGISel.cpp
@@ -1485,7 +1485,14 @@
break;
Root = FU;
VT = Root->getValueType(Root->getNumValues()-1);
+
+ // If our query node has a flag result with a use, we've walked up it. If
+ // the user (which has already been selected) has a chain or indirectly uses
+ // the chain, our WalkChainUsers predicate will not consider it. Because of
+ // this, we cannot ignore chains in this predicate.
+ IgnoreChains = false;
}
+
SmallPtrSet<SDNode*, 16> Visited;
return !findNonImmUse(Root, N.getNode(), U, Root, Visited, IgnoreChains);