Revert r166049

- In general, it's unsafe for this transformation.



git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@166135 91177308-0d34-0410-b5e6-96231b3b80d8

1 files changed, 0 insertions, 46 deletions

diff --git a/lib/CodeGen/SelectionDAG/DAGCombiner.cpp b/lib/CodeGen/SelectionDAG/DAGCombiner.cpp
index 4ac6d1b516..0c5cd3e6ca 100644
--- a/lib/CodeGen/SelectionDAG/DAGCombiner.cpp
+++ b/lib/CodeGen/SelectionDAG/DAGCombiner.cpp
@@ -5308,52 +5308,6 @@ SDValue DAGCombiner::visitTRUNCATE(SDNode *N) {
     if (Reduced.getNode())
       return Reduced;
   }
-  // fold (trunc (fptoXi x)) -> (smaller fptoXi x)
-  if ((N0.getOpcode() == ISD::FP_TO_UINT ||
-       N0.getOpcode() == ISD::FP_TO_SINT) && !LegalTypes)
-    return DAG.getNode(N0.getOpcode(), N->getDebugLoc(), VT, N0.getOperand(0));
-  // fold (trunc (concat ... x ...)) -> (concat ..., (trunc x), ...)),
-  // where ... are all 'undef'.
-  if (N0.getOpcode() == ISD::CONCAT_VECTORS && !LegalTypes) {
-    SmallVector<EVT, 8> VTs;
-    SDValue V;
-    unsigned Idx = 0;
-    unsigned NumDefs = 0;
-
-    for (unsigned i = 0, e = N0.getNumOperands(); i != e; ++i) {
-      SDValue X = N0.getOperand(i);
-      if (X.getOpcode() != ISD::UNDEF) {
-        V = X;
-        Idx = i;
-        NumDefs++;
-      }
-      // Stop if more than one members are non-undef.
-      if (NumDefs > 1)
-        break;
-      VTs.push_back(EVT::getVectorVT(*DAG.getContext(),
-                                     VT.getVectorElementType(),
-                                     X.getValueType().getVectorNumElements()));
-    }
-
-    if (NumDefs == 0)
-      return DAG.getUNDEF(VT);
-
-    if (NumDefs == 1) {
-      assert(V.getNode() && "The single defined operand is empty!");
-      SmallVector<SDValue, 8> Opnds;
-      for (unsigned i = 0, e = VTs.size(); i != e; ++i) {
-        if (i != Idx) {
-          Opnds.push_back(DAG.getUNDEF(VTs[i]));
-          continue;
-        }
-        SDValue NV = DAG.getNode(ISD::TRUNCATE, V.getDebugLoc(), VTs[i], V);
-        AddToWorkList(NV.getNode());
-        Opnds.push_back(NV);
-      }
-      return DAG.getNode(ISD::CONCAT_VECTORS, N->getDebugLoc(), VT,
-                         &Opnds[0], Opnds.size());
-    }
-  }
 
   // Simplify the operands using demanded-bits information.
   if (!VT.isVector() &&