[AArch64] Don't assume extractelt constant index when matching shuffle.

llvm-svn: 257735

1 files changed, 3 insertions, 2 deletions

diff --git a/llvm/lib/Target/AArch64/AArch64ISelLowering.cpp b/llvm/lib/Target/AArch64/AArch64ISelLowering.cpp
index 4ecfbe9e228..77637364337 100644
--- a/llvm/lib/Target/AArch64/AArch64ISelLowering.cpp
+++ b/llvm/lib/Target/AArch64/AArch64ISelLowering.cpp
@@ -4864,9 +4864,10 @@ SDValue AArch64TargetLowering::ReconstructShuffle(SDValue Op,
     SDValue V = Op.getOperand(i);
     if (V.getOpcode() == ISD::UNDEF)
       continue;
-    else if (V.getOpcode() != ISD::EXTRACT_VECTOR_ELT) {
+    else if (V.getOpcode() != ISD::EXTRACT_VECTOR_ELT ||
+             !isa<ConstantSDNode>(V.getOperand(1))) {
       // A shuffle can only come from building a vector from various
-      // elements of other vectors.
+      // elements of other vectors, provided their indices are constant.
       return SDValue();
     }