[safestack] Fix stack guard live range.

Stack guard slot is live throughout the function.

llvm-svn: 276712
diff --git a/llvm/lib/CodeGen/SafeStack.cpp b/llvm/lib/CodeGen/SafeStack.cpp
index 19cd59b..4a1b995 100644
--- a/llvm/lib/CodeGen/SafeStack.cpp
+++ b/llvm/lib/CodeGen/SafeStack.cpp
@@ -530,7 +530,7 @@
     unsigned Align =
         std::max(DL->getPrefTypeAlignment(Ty), StackGuardSlot->getAlignment());
     SSL.addObject(StackGuardSlot, getStaticAllocaAllocationSize(StackGuardSlot),
-                  Align, SSC.getLiveRange(StackGuardSlot));
+                  Align, SSC.getFullLiveRange());
   }
 
   for (Argument *Arg : ByValArguments) {