Fix llc crash on invalid input.



git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@98369 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/lib/Target/X86/AsmPrinter/X86MCInstLower.cpp b/lib/Target/X86/AsmPrinter/X86MCInstLower.cpp
index f175907..8eaeeac 100644
--- a/lib/Target/X86/AsmPrinter/X86MCInstLower.cpp
+++ b/lib/Target/X86/AsmPrinter/X86MCInstLower.cpp
@@ -358,6 +358,13 @@
       } else
         printOperand(MI, 0);
     } else {
+      if (MI->getOperand(0).getType()==MachineOperand::MO_Register &&
+          MI->getOperand(0).getReg()==0) {
+        // Suppress offset in this case, it is not meaningful.
+        O << "undef";
+        OutStreamer.AddBlankLine();
+        return;
+      }
       // Frame address.  Currently handles register +- offset only.
       assert(MI->getOperand(0).getType()==MachineOperand::MO_Register);
       assert(MI->getOperand(3).getType()==MachineOperand::MO_Immediate);