reject undef/zero labels.  This fixes PR3281:crash0[56].ll with these
diagnostics:
llvm-as: crash05.ll:1:14: invalid type for null constant
global label zeroinitializer addrspace (75), section "c"
             ^
llvm-as: crash06.ll:2:14: invalid type for null constant
  udiv label zeroinitializer, @0
             ^



git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@61681 91177308-0d34-0410-b5e6-96231b3b80d8
1 file changed