Reapply r106634, now that the bug it exposed is fixed.
llvm-svn: 106746
diff --git a/llvm/lib/CodeGen/SelectionDAG/SelectionDAG.cpp b/llvm/lib/CodeGen/SelectionDAG/SelectionDAG.cpp
index 8197076..4cbfaed 100644
--- a/llvm/lib/CodeGen/SelectionDAG/SelectionDAG.cpp
+++ b/llvm/lib/CodeGen/SelectionDAG/SelectionDAG.cpp
@@ -2470,10 +2470,18 @@
VT.getVectorNumElements() ==
Operand.getValueType().getVectorNumElements()) &&
"Vector element count mismatch!");
+
if (OpOpcode == ISD::ZERO_EXTEND || OpOpcode == ISD::SIGN_EXTEND ||
OpOpcode == ISD::ANY_EXTEND)
// (ext (zext x)) -> (zext x) and (ext (sext x)) -> (sext x)
return getNode(OpOpcode, DL, VT, Operand.getNode()->getOperand(0));
+
+ // (ext (trunx x)) -> x
+ if (OpOpcode == ISD::TRUNCATE) {
+ SDValue OpOp = Operand.getNode()->getOperand(0);
+ if (OpOp.getValueType() == VT)
+ return OpOp;
+ }
break;
case ISD::TRUNCATE:
assert(VT.isInteger() && Operand.getValueType().isInteger() &&