[PATCH] [MachineSink] Use the real post dominator tree

[Jiangning Liu]

Hi Jingyue,

It sounds not a good idea.

The failure exposed by x86 test case is for performance only rather than correctness, right?

If you have measured x86 performance, and make sure it won't generally affect performance, why can't you add //FIXME in test case instead?

Thanks,
-Jiangning

http://reviews.llvm.org/D4814