Merging r195156:
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r195156 | ributzka | 2013-11-19 13:20:17 -0800 (Tue, 19 Nov 2013) | 3 lines

[DAG] Refactor vector splitting code in SelectionDAG. No functional change intended.

Reviewed by Tom
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git-svn-id: https://llvm.org/svn/llvm-project/llvm/branches/release_34@195412 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/lib/CodeGen/SelectionDAG/SelectionDAG.cpp b/lib/CodeGen/SelectionDAG/SelectionDAG.cpp
index 1210534..45d5a4f 100644
--- a/lib/CodeGen/SelectionDAG/SelectionDAG.cpp
+++ b/lib/CodeGen/SelectionDAG/SelectionDAG.cpp
@@ -869,7 +869,7 @@
 
 // EntryNode could meaningfully have debug info if we can find it...
 SelectionDAG::SelectionDAG(const TargetMachine &tm, CodeGenOpt::Level OL)
-  : TM(tm), TSI(*tm.getSelectionDAGInfo()), TTI(0), OptLevel(OL),
+  : TM(tm), TSI(*tm.getSelectionDAGInfo()), TTI(0), TLI(0), OptLevel(OL),
     EntryNode(ISD::EntryToken, 0, DebugLoc(), getVTList(MVT::Other)),
     Root(getEntryNode()), NewNodesMustHaveLegalTypes(false),
     UpdateListeners(0) {
@@ -877,9 +877,11 @@
   DbgInfo = new SDDbgInfo();
 }
 
-void SelectionDAG::init(MachineFunction &mf, const TargetTransformInfo *tti) {
+void SelectionDAG::init(MachineFunction &mf, const TargetTransformInfo *tti,
+                        const TargetLowering *tli) {
   MF = &mf;
   TTI = tti;
+  TLI = tli;
   Context = &mf.getFunction()->getContext();
 }
 
@@ -6406,6 +6408,38 @@
   return 0;
 }
 
+/// GetSplitDestVTs - Compute the VTs needed for the low/hi parts of a type
+/// which is split (or expanded) into two not necessarily identical pieces.
+std::pair<EVT, EVT> SelectionDAG::GetSplitDestVTs(const EVT &VT) const {
+  // Currently all types are split in half.
+  EVT LoVT, HiVT;
+  if (!VT.isVector()) {
+    LoVT = HiVT = TLI->getTypeToTransformTo(*getContext(), VT);
+  } else {
+    unsigned NumElements = VT.getVectorNumElements();
+    assert(!(NumElements & 1) && "Splitting vector, but not in half!");
+    LoVT = HiVT = EVT::getVectorVT(*getContext(), VT.getVectorElementType(),
+                                   NumElements/2);
+  }
+  return std::make_pair(LoVT, HiVT);
+}
+
+/// SplitVector - Split the vector with EXTRACT_SUBVECTOR and return the
+/// low/high part.
+std::pair<SDValue, SDValue>
+SelectionDAG::SplitVector(const SDValue &N, const SDLoc &DL, const EVT &LoVT,
+                          const EVT &HiVT) {
+  assert(LoVT.getVectorNumElements() + HiVT.getVectorNumElements() <=
+         N.getValueType().getVectorNumElements() &&
+         "More vector elements requested than available!");
+  SDValue Lo, Hi;
+  Lo = getNode(ISD::EXTRACT_SUBVECTOR, DL, LoVT, N,
+               getConstant(0, TLI->getVectorIdxTy()));
+  Hi = getNode(ISD::EXTRACT_SUBVECTOR, DL, HiVT, N,
+               getConstant(LoVT.getVectorNumElements(), TLI->getVectorIdxTy()));
+  return std::make_pair(Lo, Hi);
+}
+
 // getAddressSpace - Return the address space this GlobalAddress belongs to.
 unsigned GlobalAddressSDNode::getAddressSpace() const {
   return getGlobal()->getType()->getAddressSpace();