diff options
Diffstat (limited to 'lib/CodeGen/SelectionDAG/DAGCombiner.cpp')
| -rw-r--r-- | lib/CodeGen/SelectionDAG/DAGCombiner.cpp | 4 |
1 files changed, 4 insertions, 0 deletions
diff --git a/lib/CodeGen/SelectionDAG/DAGCombiner.cpp b/lib/CodeGen/SelectionDAG/DAGCombiner.cpp index 6cd66c7c19..b7f6853f74 100644 --- a/lib/CodeGen/SelectionDAG/DAGCombiner.cpp +++ b/lib/CodeGen/SelectionDAG/DAGCombiner.cpp @@ -1546,6 +1546,10 @@ SDOperand DAGCombiner::visitSIGN_EXTEND(SDNode *N) { // fold (sext (sextload x)) -> (sextload x) if (N0.getOpcode() == ISD::SEXTLOAD && VT == N0.getValueType()) return N0; + // fold (sext (truncate x)) -> (sextinreg x) iff x size == sext size. + if (N0.getOpcode() == ISD::TRUNCATE && N0.getOperand(0).getValueType() == VT) + return DAG.getNode(ISD::SIGN_EXTEND_INREG, VT, N0.getOperand(0), + DAG.getValueType(N0.getValueType())); // fold (sext (load x)) -> (sextload x) if (N0.getOpcode() == ISD::LOAD && N0.hasOneUse()) { SDOperand ExtLoad = DAG.getExtLoad(ISD::SEXTLOAD, VT, N0.getOperand(0), |