[X86][SelectionDAG] Make sure we explicitly sign extend the index when type promoting the index of scatter and gather.

Type promotion makes no guarantee about the contents of the promoted bits. Since the gather/scatter instruction will use the bits to calculate addresses, we need to ensure they aren't garbage.

llvm-svn: 319520

1 files changed, 6 insertions, 0 deletions

diff --git a/llvm/lib/CodeGen/SelectionDAG/LegalizeIntegerTypes.cpp b/llvm/lib/CodeGen/SelectionDAG/LegalizeIntegerTypes.cpp
index 83daa8c4029..d86ed0b6f8a 100644
--- a/llvm/lib/CodeGen/SelectionDAG/LegalizeIntegerTypes.cpp
+++ b/llvm/lib/CodeGen/SelectionDAG/LegalizeIntegerTypes.cpp
@@ -1253,6 +1253,9 @@ SDValue DAGTypeLegalizer::PromoteIntOp_MGATHER(MaskedGatherSDNode *N,
     // The Mask
     EVT DataVT = N->getValueType(0);
     NewOps[OpNo] = PromoteTargetBoolean(N->getOperand(OpNo), DataVT);
+  } else if (OpNo == 4) {
+    // Need to sign extend the index since the bits will likely be used.
+    NewOps[OpNo] = SExtPromotedInteger(N->getOperand(OpNo));
   } else
     NewOps[OpNo] = GetPromotedInteger(N->getOperand(OpNo));
 
@@ -1273,6 +1276,9 @@ SDValue DAGTypeLegalizer::PromoteIntOp_MSCATTER(MaskedScatterSDNode *N,
     // The Mask
     EVT DataVT = N->getValue().getValueType();
     NewOps[OpNo] = PromoteTargetBoolean(N->getOperand(OpNo), DataVT);
+  } else if (OpNo == 4) {
+    // Need to sign extend the index since the bits will likely be used.
+    NewOps[OpNo] = SExtPromotedInteger(N->getOperand(OpNo));
   } else
     NewOps[OpNo] = GetPromotedInteger(N->getOperand(OpNo));
   return SDValue(DAG.UpdateNodeOperands(N, NewOps), 0);