From 55e81eb49fb3779ea658d05d5c84e08da3f42136 Mon Sep 17 00:00:00 2001 From: Chris Lattner Date: Fri, 5 Mar 2010 06:19:13 +0000 Subject: 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. llvm-svn: 97791 --- llvm/lib/CodeGen/SelectionDAG/SelectionDAGISel.cpp | 7 +++++++ 1 file changed, 7 insertions(+) (limited to 'llvm/lib/CodeGen') diff --git a/llvm/lib/CodeGen/SelectionDAG/SelectionDAGISel.cpp b/llvm/lib/CodeGen/SelectionDAG/SelectionDAGISel.cpp index b9ec4c46f3b..f426fb1f3fa 100644 --- a/llvm/lib/CodeGen/SelectionDAG/SelectionDAGISel.cpp +++ b/llvm/lib/CodeGen/SelectionDAG/SelectionDAGISel.cpp @@ -1485,7 +1485,14 @@ bool SelectionDAGISel::IsLegalToFold(SDValue N, SDNode *U, SDNode *Root, 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 Visited; return !findNonImmUse(Root, N.getNode(), U, Root, Visited, IgnoreChains); -- cgit v1.2.3