Fix a long standing tail call optimization bug. When a libcall is emitted
legalizer always use the DAG entry node. This is wrong when the libcall is
emitted as a tail call since it effectively folds the return node. If
the return node's input chain is not the entry (i.e. call, load, or store)
use that as the tail call input chain.
PR12419
rdar://9770785
rdar://11195178
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@154370 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/lib/CodeGen/Analysis.cpp b/lib/CodeGen/Analysis.cpp
index 14e14c3..00874d4 100644
--- a/lib/CodeGen/Analysis.cpp
+++ b/lib/CodeGen/Analysis.cpp
@@ -290,7 +290,7 @@
}
bool llvm::isInTailCallPosition(SelectionDAG &DAG, SDNode *Node,
- const TargetLowering &TLI) {
+ SDValue &Chain, const TargetLowering &TLI) {
const Function *F = DAG.getMachineFunction().getFunction();
// Conservatively require the attributes of the call to match those of
@@ -304,5 +304,5 @@
return false;
// Check if the only use is a function return node.
- return TLI.isUsedByReturnOnly(Node);
+ return TLI.isUsedByReturnOnly(Node, Chain);
}