Update makeLibCall to return both the call and the chain associated with the libcall instead of just the call. This allows us to specify libcalls that return void.

LowerCallTo returns a pair with the return value of the call as the first
element and the chain associated with the return value as the second element. If
we lower a call that has a void return value, LowerCallTo returns an SDValue
with a NULL SDNode and the chain for the call. Thus makeLibCall by just
returning the first value makes it impossible for you to set up the chain so
that the call is not eliminated as dead code.

I also updated all references to makeLibCall to reflect the new return type.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@188300 91177308-0d34-0410-b5e6-96231b3b80d8

1 files changed, 7 insertions, 4 deletions

diff --git a/lib/CodeGen/SelectionDAG/LegalizeTypes.cpp b/lib/CodeGen/SelectionDAG/LegalizeTypes.cpp
index fd770d140b..b078b085c1 100644
--- a/lib/CodeGen/SelectionDAG/LegalizeTypes.cpp
+++ b/lib/CodeGen/SelectionDAG/LegalizeTypes.cpp
@@ -1024,20 +1024,23 @@ SDValue DAGTypeLegalizer::LibCallify(RTLIB::Libcall LC, SDNode *N,
   unsigned NumOps = N->getNumOperands();
   SDLoc dl(N);
   if (NumOps == 0) {
-    return TLI.makeLibCall(DAG, LC, N->getValueType(0), 0, 0, isSigned, dl);
+    return TLI.makeLibCall(DAG, LC, N->getValueType(0), 0, 0, isSigned,
+                           dl).first;
   } else if (NumOps == 1) {
     SDValue Op = N->getOperand(0);
-    return TLI.makeLibCall(DAG, LC, N->getValueType(0), &Op, 1, isSigned, dl);
+    return TLI.makeLibCall(DAG, LC, N->getValueType(0), &Op, 1, isSigned,
+                           dl).first;
   } else if (NumOps == 2) {
     SDValue Ops[2] = { N->getOperand(0), N->getOperand(1) };
-    return TLI.makeLibCall(DAG, LC, N->getValueType(0), Ops, 2, isSigned, dl);
+    return TLI.makeLibCall(DAG, LC, N->getValueType(0), Ops, 2, isSigned,
+                           dl).first;
   }
   SmallVector<SDValue, 8> Ops(NumOps);
   for (unsigned i = 0; i < NumOps; ++i)
     Ops[i] = N->getOperand(i);
 
   return TLI.makeLibCall(DAG, LC, N->getValueType(0),
-                         &Ops[0], NumOps, isSigned, dl);
+                         &Ops[0], NumOps, isSigned, dl).first;
 }
 
 // ExpandChainLibCall - Expand a node into a call to a libcall. Similar to