Implement four-wide shuffle with 2 shufps if no more than two elements come
from each vector. e.g.
shuffle(G1, G2, 7, 1, 5, 2)
==>
movaps _G2, %xmm0
shufps $151, _G1, %xmm0
shufps $216, %xmm0, %xmm0
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@28011 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/lib/Target/X86/X86ISelLowering.cpp b/lib/Target/X86/X86ISelLowering.cpp
index b0dd6a6..06c6d80 100644
--- a/lib/Target/X86/X86ISelLowering.cpp
+++ b/lib/Target/X86/X86ISelLowering.cpp
@@ -2676,10 +2676,55 @@
}
if (NumElems == 4) {
- // Break it into (shuffle shuffle_hi, shuffle_lo).
MVT::ValueType MaskVT = PermMask.getValueType();
MVT::ValueType MaskEVT = MVT::getVectorBaseType(MaskVT);
- std::map<unsigned, std::pair<int, int> > Locs;
+ std::vector<std::pair<int, int> > Locs;
+ Locs.reserve(NumElems);
+ std::vector<SDOperand> Mask1(NumElems, DAG.getNode(ISD::UNDEF, MaskEVT));
+ std::vector<SDOperand> Mask2(NumElems, DAG.getNode(ISD::UNDEF, MaskEVT));
+ unsigned NumHi = 0;
+ unsigned NumLo = 0;
+ // If no more than two elements come from either vector. This can be
+ // implemented with two shuffles. First shuffle gather the elements.
+ // The second shuffle, which takes the first shuffle as both of its
+ // vector operands, put the elements into the right order.
+ for (unsigned i = 0; i != NumElems; ++i) {
+ SDOperand Elt = PermMask.getOperand(i);
+ if (Elt.getOpcode() == ISD::UNDEF) {
+ Locs[i] = std::make_pair(-1, -1);
+ } else {
+ unsigned Val = cast<ConstantSDNode>(Elt)->getValue();
+ if (Val < NumElems) {
+ Locs[i] = std::make_pair(0, NumLo);
+ Mask1[NumLo] = Elt;
+ NumLo++;
+ } else {
+ Locs[i] = std::make_pair(1, NumHi);
+ if (2+NumHi < NumElems)
+ Mask1[2+NumHi] = Elt;
+ NumHi++;
+ }
+ }
+ }
+ if (NumLo <= 2 && NumHi <= 2) {
+ V1 = DAG.getNode(ISD::VECTOR_SHUFFLE, VT, V1, V2,
+ DAG.getNode(ISD::BUILD_VECTOR, MaskVT, Mask1));
+ for (unsigned i = 0; i != NumElems; ++i) {
+ if (Locs[i].first == -1)
+ continue;
+ else {
+ unsigned Idx = (i < NumElems/2) ? 0 : NumElems;
+ Idx += Locs[i].first * (NumElems/2) + Locs[i].second;
+ Mask2[i] = DAG.getConstant(Idx, MaskEVT);
+ }
+ }
+
+ return DAG.getNode(ISD::VECTOR_SHUFFLE, VT, V1, V1,
+ DAG.getNode(ISD::BUILD_VECTOR, MaskVT, Mask2));
+ }
+
+ // Break it into (shuffle shuffle_hi, shuffle_lo).
+ Locs.clear();
std::vector<SDOperand> LoMask(NumElems, DAG.getNode(ISD::UNDEF, MaskEVT));
std::vector<SDOperand> HiMask(NumElems, DAG.getNode(ISD::UNDEF, MaskEVT));
std::vector<SDOperand> *MaskPtr = &LoMask;