Added instregex support to TableGen subtarget emitter.

This allows the processor-specific machine model to override selected
base opcodes without any fanciness.
e.g. InstRW<[CoreXWriteVANDP], (instregex "VANDP")>.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@165180 91177308-0d34-0410-b5e6-96231b3b80d8
4 files changed