1 files changed, 5 insertions, 1 deletions
diff --git a/lib/CodeGen/SelectionDAG/LegalizeIntegerTypes.cpp b/lib/CodeGen/SelectionDAG/LegalizeIntegerTypes.cpp
index 1a92d4a8b595..a37f4e1116b4 100644
--- a/lib/CodeGen/SelectionDAG/LegalizeIntegerTypes.cpp
+++ b/lib/CodeGen/SelectionDAG/LegalizeIntegerTypes.cpp
@@ -428,7 +428,11 @@ SDValue DAGTypeLegalizer::PromoteIntRes_FP_TO_XINT(SDNode *N) {
   // Assert that the converted value fits in the original type.  If it doesn't
   // (eg: because the value being converted is too big), then the result of the
   // original operation was undefined anyway, so the assert is still correct.
-  return DAG.getNode(NewOpc == ISD::FP_TO_UINT ?
+  //
+  // NOTE: fp-to-uint to fp-to-sint promotion guarantees zero extend. For example:
+  //   before legalization: fp-to-uint16, 65534. -> 0xfffe
+  //   after legalization: fp-to-sint32, 65534. -> 0x0000fffe
+  return DAG.getNode(N->getOpcode() == ISD::FP_TO_UINT ?
                      ISD::AssertZext : ISD::AssertSext, dl, NVT, Res,
                      DAG.getValueType(N->getValueType(0).getScalarType()));
 }