Minor optimization. sign-ext/anyext of undef is still undef.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@127598 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/lib/CodeGen/SelectionDAG/SelectionDAG.cpp b/lib/CodeGen/SelectionDAG/SelectionDAG.cpp
index 8deaae9..2c97d35 100644
--- a/lib/CodeGen/SelectionDAG/SelectionDAG.cpp
+++ b/lib/CodeGen/SelectionDAG/SelectionDAG.cpp
@@ -2482,6 +2482,8 @@
"Vector element count mismatch!");
if (OpOpcode == ISD::SIGN_EXTEND || OpOpcode == ISD::ZERO_EXTEND)
return getNode(OpOpcode, DL, VT, Operand.getNode()->getOperand(0));
+ else if (OpOpcode == ISD::UNDEF)
+ return getUNDEF(VT);
break;
case ISD::ZERO_EXTEND:
assert(VT.isInteger() && Operand.getValueType().isInteger() &&
@@ -2512,6 +2514,8 @@
OpOpcode == ISD::ANY_EXTEND)
// (ext (zext x)) -> (zext x) and (ext (sext x)) -> (sext x)
return getNode(OpOpcode, DL, VT, Operand.getNode()->getOperand(0));
+ else if (OpOpcode == ISD::UNDEF)
+ return getUNDEF(VT);
// (ext (trunx x)) -> x
if (OpOpcode == ISD::TRUNCATE) {