Avoid breaking vstd when reg_sequence is not used.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@103513 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/lib/Target/ARM/NEONPreAllocPass.cpp b/lib/Target/ARM/NEONPreAllocPass.cpp
index 5a5dd29..d1b1bc8 100644
--- a/lib/Target/ARM/NEONPreAllocPass.cpp
+++ b/lib/Target/ARM/NEONPreAllocPass.cpp
@@ -419,7 +419,8 @@
     unsigned FirstOpnd, NumRegs, Offset, Stride;
     if (!isNEONMultiRegOp(MI->getOpcode(), FirstOpnd, NumRegs, Offset, Stride))
       continue;
-    if (FormsRegSequence(MI, FirstOpnd, NumRegs))
+    if (llvm::ModelWithRegSequence() &&
+        FormsRegSequence(MI, FirstOpnd, NumRegs))
       continue;
 
     MachineBasicBlock::iterator NextI = llvm::next(MBBI);