fold insertelement(buildvector) -> buildvector if the inserted element # is

a constant.  This implements test_constant_insert in CodeGen/Generic/vector.ll


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@26851 91177308-0d34-0410-b5e6-96231b3b80d8

1 files changed, 42 insertions, 0 deletions

diff --git a/lib/CodeGen/SelectionDAG/DAGCombiner.cpp b/lib/CodeGen/SelectionDAG/DAGCombiner.cpp
index 6152d228cc..8a0f488fde 100644
--- a/lib/CodeGen/SelectionDAG/DAGCombiner.cpp
+++ b/lib/CodeGen/SelectionDAG/DAGCombiner.cpp
@@ -209,6 +209,8 @@ namespace {
     SDOperand visitBR_CC(SDNode *N);
     SDOperand visitLOAD(SDNode *N);
     SDOperand visitSTORE(SDNode *N);
+    SDOperand visitINSERT_VECTOR_ELT(SDNode *N);
+    SDOperand visitVINSERT_VECTOR_ELT(SDNode *N);
 
     SDOperand ReassociateOps(unsigned Opc, SDOperand LHS, SDOperand RHS);
     
@@ -640,6 +642,8 @@ SDOperand DAGCombiner::visit(SDNode *N) {
   case ISD::BR_CC:              return visitBR_CC(N);
   case ISD::LOAD:               return visitLOAD(N);
   case ISD::STORE:              return visitSTORE(N);
+  case ISD::INSERT_VECTOR_ELT:  return visitINSERT_VECTOR_ELT(N);
+  case ISD::VINSERT_VECTOR_ELT: return visitVINSERT_VECTOR_ELT(N);
   }
   return SDOperand();
 }
@@ -2290,6 +2294,44 @@ SDOperand DAGCombiner::visitSTORE(SDNode *N) {
   return SDOperand();
 }
 
+SDOperand DAGCombiner::visitINSERT_VECTOR_ELT(SDNode *N) {
+  SDOperand InVec = N->getOperand(0);
+  SDOperand InVal = N->getOperand(1);
+  SDOperand EltNo = N->getOperand(2);
+  
+  // If the invec is a BUILD_VECTOR and if EltNo is a constant, build a new
+  // vector with the inserted element.
+  if (InVec.getOpcode() == ISD::BUILD_VECTOR && isa<ConstantSDNode>(EltNo)) {
+    unsigned Elt = cast<ConstantSDNode>(EltNo)->getValue();
+    std::vector<SDOperand> Ops(InVec.Val->op_begin(), InVec.Val->op_end());
+    if (Elt < Ops.size())
+      Ops[Elt] = InVal;
+    return DAG.getNode(ISD::BUILD_VECTOR, InVec.getValueType(), Ops);
+  }
+  
+  return SDOperand();
+}
+
+SDOperand DAGCombiner::visitVINSERT_VECTOR_ELT(SDNode *N) {
+  SDOperand InVec = N->getOperand(0);
+  SDOperand InVal = N->getOperand(1);
+  SDOperand EltNo = N->getOperand(2);
+  SDOperand NumElts = N->getOperand(3);
+  SDOperand EltType = N->getOperand(4);
+  
+  // If the invec is a VBUILD_VECTOR and if EltNo is a constant, build a new
+  // vector with the inserted element.
+  if (InVec.getOpcode() == ISD::VBUILD_VECTOR && isa<ConstantSDNode>(EltNo)) {
+    unsigned Elt = cast<ConstantSDNode>(EltNo)->getValue();
+    std::vector<SDOperand> Ops(InVec.Val->op_begin(), InVec.Val->op_end());
+    if (Elt < Ops.size()-2)
+      Ops[Elt] = InVal;
+    return DAG.getNode(ISD::VBUILD_VECTOR, InVec.getValueType(), Ops);
+  }
+  
+  return SDOperand();
+}
+
 SDOperand DAGCombiner::SimplifySelect(SDOperand N0, SDOperand N1, SDOperand N2){
   assert(N0.getOpcode() ==ISD::SETCC && "First argument must be a SetCC node!");