This is the fix for PR24072:
X86 instructions jrcxz/jecxz/jcxz performs short jumps if rcx/ecx/cx register is 0
The maximum relative offset for a forward short jump is 127 Bytes (0x7F).
The maximum relative offset for a backward short jump is 128 Bytes (0x80).
Gnu assembler warns when the distance of the jump exceeds the maximum but llvm-as does not.
The fix for that problem was already presented for review : D36991
The llvm codebase changed since August of 2017, thus it does not pass
current check-all testing. I limited it for only PCRel fixups and to
not check not-resolved symbols.