teach dag combiner how to eliminate MERGE_VALUES nodes.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@47052 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/lib/CodeGen/SelectionDAG/DAGCombiner.cpp b/lib/CodeGen/SelectionDAG/DAGCombiner.cpp
index a2f36f3..29a31e4 100644
--- a/lib/CodeGen/SelectionDAG/DAGCombiner.cpp
+++ b/lib/CodeGen/SelectionDAG/DAGCombiner.cpp
@@ -137,6 +137,7 @@
// otherwise - N should be replaced by the returned Operand.
//
SDOperand visitTokenFactor(SDNode *N);
+ SDOperand visitMERGE_VALUES(SDNode *N);
SDOperand visitADD(SDNode *N);
SDOperand visitSUB(SDNode *N);
SDOperand visitADDC(SDNode *N);
@@ -662,6 +663,7 @@
switch(N->getOpcode()) {
default: break;
case ISD::TokenFactor: return visitTokenFactor(N);
+ case ISD::MERGE_VALUES: return visitMERGE_VALUES(N);
case ISD::ADD: return visitADD(N);
case ISD::SUB: return visitSUB(N);
case ISD::ADDC: return visitADDC(N);
@@ -837,6 +839,18 @@
return Result;
}
+/// MERGE_VALUES can always be eliminated.
+SDOperand DAGCombiner::visitMERGE_VALUES(SDNode *N) {
+ WorkListRemover DeadNodes(*this);
+ for (unsigned i = 0, e = N->getNumOperands(); i != e; ++i)
+ DAG.ReplaceAllUsesOfValueWith(SDOperand(N, i), N->getOperand(i),
+ &DeadNodes);
+ removeFromWorkList(N);
+ DAG.DeleteNode(N);
+ return SDOperand(N, 0); // Return N so it doesn't get rechecked!
+}
+
+
static
SDOperand combineShlAddConstant(SDOperand N0, SDOperand N1, SelectionDAG &DAG) {
MVT::ValueType VT = N0.getValueType();