Temporarily revert r48491. It's breaking test/CodeGen/X86/xorl.ll.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@48510 91177308-0d34-0410-b5e6-96231b3b80d8

1 files changed, 0 insertions, 26 deletions

diff --git a/lib/CodeGen/SelectionDAG/DAGCombiner.cpp b/lib/CodeGen/SelectionDAG/DAGCombiner.cpp
index 737d9661fd..acc00fd58b 100644
--- a/lib/CodeGen/SelectionDAG/DAGCombiner.cpp
+++ b/lib/CodeGen/SelectionDAG/DAGCombiner.cpp
@@ -2374,32 +2374,6 @@ SDOperand DAGCombiner::visitSRA(SDNode *N) {
                          DAG.getValueType(EVT));
   }
   
-  // fold sra (shl X, m), result_size - n 
-  // -> (sign_extend (trunc (shl X, result_size - n - m))) for 
-  // result_size - n != m. If truncate is free for the target sext(shl) is 
-  // likely to result in better code.
-  if (N0.getOpcode() == ISD::SHL) {
-    // Get the two constanst of the shifts, CN0 = m, CN = n.
-    const ConstantSDNode *N01C = dyn_cast<ConstantSDNode>(N0.getOperand(1));
-    if (N01C && N1C) {
-      // Determine if the truncate type's bitsize would correspond to
-      // an integer type for this target.
-      unsigned VTValSize = MVT::getSizeInBits(VT);
-      MVT::ValueType TruncVT = MVT::getIntegerType(VTValSize - N1C->getValue());
-      unsigned ShiftAmt = N1C->getValue() - N01C->getValue();
-      
-      // If the shift wouldn't be a noop, the truncated type is an actual type, 
-      // and the truncate is free, then proceed with the transform.
-      if (ShiftAmt != 0 && 
-          !MVT::isExtendedVT(TruncVT) && TLI.isTruncateFree(VT, TruncVT)) {
-        SDOperand Amt = DAG.getConstant(ShiftAmt, TLI.getShiftAmountTy());
-        SDOperand Shift = DAG.getNode(ISD::SRL, VT, N0.getOperand(0), Amt);
-        SDOperand Trunc = DAG.getNode(ISD::TRUNCATE, TruncVT, Shift);
-        return DAG.getNode(ISD::SIGN_EXTEND, N->getValueType(0), Trunc);
-      }
-    }
-  }
-  
   // fold (sra (sra x, c1), c2) -> (sra x, c1+c2)
   if (N1C && N0.getOpcode() == ISD::SRA) {
     if (ConstantSDNode *C1 = dyn_cast<ConstantSDNode>(N0.getOperand(1))) {