Improve EXTRACT_VECTOR_ELT patch based on comments from Duncan

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@95012 91177308-0d34-0410-b5e6-96231b3b80d8

1 files changed, 9 insertions, 6 deletions

diff --git a/lib/CodeGen/SelectionDAG/SelectionDAG.cpp b/lib/CodeGen/SelectionDAG/SelectionDAG.cpp
index 2e92f8f1fd..5315b21260 100644
--- a/lib/CodeGen/SelectionDAG/SelectionDAG.cpp
+++ b/lib/CodeGen/SelectionDAG/SelectionDAG.cpp
@@ -2764,13 +2764,16 @@ SDValue SelectionDAG::getNode(unsigned Opcode, DebugLoc DL, EVT VT,
     // 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 && VT == N1.getOperand(1).getValueType())
-        return N1.getOperand(1);
-      // If the indices are known different, extract the element from
+      // If the indices are the same, return the inserted element else
+      // if the indices are known different, extract the element from
       // the original vector.
-      else if (isa<ConstantSDNode>(N1.getOperand(2)) &&
-               isa<ConstantSDNode>(N2))
+      if (N1.getOperand(2) == N2) {
+        if (VT == N1.getOperand(1).getValueType())
+          return N1.getOperand(1);
+        else
+          return getSExtOrTrunc(N1.getOperand(1), DL, VT);
+      } else if (isa<ConstantSDNode>(N1.getOperand(2)) &&
+                 isa<ConstantSDNode>(N2))
         return getNode(ISD::EXTRACT_VECTOR_ELT, DL, VT, N1.getOperand(0), N2);
     }
     break;