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[AVX] When joining two XMM registers into a YMM register, make sure that the 

lower XMM register gets in first. This will allow the SUBREG pattern to
elliminate the first vector insertion. 

llvm-svn: 137310
This commit is contained in:
Nadav Rotem 2011-08-11 16:49:36 +00:00
parent 22a9d0f316
commit 61140e1028
1 changed files with 32 additions and 0 deletions
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32
llvm/lib/CodeGen/SelectionDAG/DAGCombiner.cpp
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@ -213,6 +213,7 @@ namespace {
SDValue visitLOAD(SDNode *N);
SDValue visitSTORE(SDNode *N);
SDValue visitINSERT_VECTOR_ELT(SDNode *N);
SDValue visitINSERT_SUBVECTOR(SDNode *N);
SDValue visitEXTRACT_VECTOR_ELT(SDNode *N);
SDValue visitBUILD_VECTOR(SDNode *N);
SDValue visitCONCAT_VECTORS(SDNode *N);
@ -1102,6 +1103,7 @@ SDValue DAGCombiner::visit(SDNode *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::INSERT_SUBVECTOR: return visitINSERT_SUBVECTOR(N);
case ISD::EXTRACT_VECTOR_ELT: return visitEXTRACT_VECTOR_ELT(N);
case ISD::BUILD_VECTOR: return visitBUILD_VECTOR(N);
case ISD::CONCAT_VECTORS: return visitCONCAT_VECTORS(N);
@ -7136,6 +7138,36 @@ SDValue DAGCombiner::visitMEMBARRIER(SDNode* N) {
}
}
SDValue DAGCombiner::visitINSERT_SUBVECTOR(SDNode* N) {
DebugLoc dl = N->getDebugLoc();
EVT VT = N->getValueType(0);
// When inserting a subvector into a vector, make sure to start
// inserting starting the Zero index. This will allow making the
// first insertion using a subreg insertion, and save a register.
SDValue V = N->getOperand(0);
if (V->getOpcode() == ISD::INSERT_SUBVECTOR && V->hasOneUse()) {
ConstantSDNode *N_Idx = dyn_cast<ConstantSDNode>(N->getOperand(2));
ConstantSDNode *V_Idx = dyn_cast<ConstantSDNode>(V->getOperand(2));
uint64_t Nc = N_Idx->getZExtValue();
uint64_t Vc = V_Idx->getZExtValue();
// Reorder insertion to vector
if (Nc < Vc) {
SDValue NewV = DAG.getNode(ISD::INSERT_SUBVECTOR, dl, VT,
V->getOperand(0),
N->getOperand(1),
N->getOperand(2));
return DAG.getNode(ISD::INSERT_SUBVECTOR, dl, VT,
NewV,
V->getOperand(1),
V->getOperand(2));
}
}
return SDValue();
}
/// XformToShuffleWithZero - Returns a vector_shuffle if it able to transform
/// an AND to a vector_shuffle with the destination vector and a zero vector.
/// e.g. AND V, <0xffffffff, 0, 0xffffffff, 0>. ==>