fix a really nasty bug I introduced in r95693: r12 (and r12d, 
r12b, etc) also encodes to a R/M value of 4, which is just
as illegal as ESP/RSP for the non-sib version an address.

This fixes x86-64 jit miscompilations of a bunch of programs.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@95866 91177308-0d34-0410-b5e6-96231b3b80d8
2 files changed