In the case of an extractelement on an insertelement value,
the element indices may be equal if either one is not a
constant.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@63311 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/lib/CodeGen/SelectionDAG/SelectionDAG.cpp b/lib/CodeGen/SelectionDAG/SelectionDAG.cpp
index ab2c832..16f17e5 100644
--- a/lib/CodeGen/SelectionDAG/SelectionDAG.cpp
+++ b/lib/CodeGen/SelectionDAG/SelectionDAG.cpp
@@ -2597,9 +2597,13 @@
// EXTRACT_VECTOR_ELT of INSERT_VECTOR_ELT is often formed when vector
// operations are lowered to scalars.
if (N1.getOpcode() == ISD::INSERT_VECTOR_ELT) {
+ // If the indices are the same, return the inserted element.
if (N1.getOperand(2) == N2)
return N1.getOperand(1);
- else
+ // If the indices are known different, extract the element from
+ // the original vector.
+ else if (isa<ConstantSDNode>(N1.getOperand(2)) &&
+ isa<ConstantSDNode>(N2))
return getNode(ISD::EXTRACT_VECTOR_ELT, VT, N1.getOperand(0), N2);
}
break;